Hi, welcome to Taiga Bonzai, many of the questions we receive are mostly related to ‘Plant husbandry’ for example, “why do seedlings and young trees have their foliage turn brown then die?”

Introduction – to summarise the above question would not be helpful, because this is a lengthy subject with many connecting factors. These will be discussed in the coming articles.

Germination – is defined into two categories Epigeal (above ground) and Hypogeal. (below ground) As a seed germinates the first structure to emerge from most seeds is a root from the embryonic called a radicle. This primary root referred to as a taproot has smaller lateral roots (secondary roots) sprouting from the taproot. These in turn produce even smaller lateral roots, (tertiary roots) which serve to increase the surface area for water and mineral absorption.

The above images show the stages of germination from the radicle to the first true set of leaves and needles respectfully. Cotyledons are the first leaves produced by plants, but are not considered true leaves. They are sometimes referred to as ‘seed leaves’, because they are actually part of the seed or embryo of the plant. These seed leaves serve to access the stored nutrients in the seed, feeding it until the true leaves develop and begin photosynthesising.

Root growth – roots grow in length from their ends only, the very tip of the root is covered by a thimble-shaped root cap called the calyptra, which protects the growing tip as it makes its way through the soil.

Behind the root cap lies the apical meristem, here cells are produced some are added to the root cap. But the majority are added to the region of elongation, which lies just above the meristematic area.

Above this lies the region of maturation where the primary tissues of the root mature, completing the process of cell differentiation that actually begins in the upper portion of the meristematic region. (shown below)

Aerial roots – called adventitious roots arise from an organ other than the root, for example from a stem or leaf. These adventitious roots often referred to as aerial roots can hang long distances before coming into contact with the soil or remain dangling in the air.

Some of these including the Screw pine and banyan do assist in supporting the plant in the soil. Aerial roots are the primary means of attachment to non-soil surfaces such as buildings, rocks and other plants for example. The Ficus watkinsiana family Moraceae (strangler fig) named for their pattern of growth upon host trees, which often results in the host’s death.

A number of other specialized roots exist among vascular plants for example. Pneumatophores an aerial root specialising in gaseous exchange are commonly found in mangrove species that grow in saline mud flats. These are lateral roots that grow upward out of the mud and water to function as the site of oxygen intake for the submerged primary root system.

Other root systems – the roots of certain parasitic plants are highly modified into haustoria, a rootlike structure that grows into or around another structure to absorb water or nutrients. Mistletoe and members of the broomrape family are good examples of this.

Many plant roots also form intricate associations with mycorrhizal soil fungi, a number of non-photosynthetic mycoheterotrophic plants including the Indian pipe Monotropa uniflora rely exclusively on these fungi for nutrition.

Root functionality – the primary tissues of the root are from outermost to innermost, the epidermis, cortex and vascular cylinder. The epidermis is composed of thin-walled cells and is normally only one cell layer in thickness.

Water absorption and dissolved minerals occur through the epidermis, a process enhanced in most land plants via the presence of root hairs. These slender tubular extensions of the epidermal cell wall are only found in the region of maturation.

The absorption of water is achieved via osmosis process, because (a) water is present in higher concentrations in the soil than within the epidermal cells. Here salts, sugars and other dissolved organic products are contained.

(b) The membrane of the epidermal cells is permeable to water, but not to many of the substances dissolved in the internal fluid. These conditions create an osmotic gradient, whereby water flows into the epidermal cells. This flow exerts a force called root pressure, that helps drive the water through the roots.

The cortex conducts water and dissolved minerals across the root from the epidermis to the vascular cylinder, then transported to the rest of the plant. The cortex also stores food transported downward from the leaves through the vascular tissues. The innermost layer of the cortex consists of a tightly packed layer of cells called the endodermis, which regulates the flow of materials between the cortex and the vascular tissues.

Why no tap root? – In bonsai many practitioners remove the ‘tap root’, but the ‘tap root’ enables stability and water absorption so why remove it? The following species have rather large tap roots Oak Quercus, Black Walnut Juglans nigra, Silver Fir Abies alba and White Mulberry Morus alba.

Coniferous species contrary to popular belief do not have long tap roots. Their lateral roots and tertiary roots spread outward and grow downward which gives stability. However, there are some exceptions including the Long Leaf pine Pinus palustris that have large tap roots.

In order for these and many other species of tree to become bonsai the roots have to be pruned and the more vigorous the root growth the more pruning is required. In Japan and China young trees are planted in deep pots to encourage root growth and after a few seasons they have their tap roots removed to allow the lateral and tertiary roots to develop and thicken; these roots if near the base of the trunk are the potential nebari.

Root damage – many plants will survive and recover from root damage providing the damage does not exceed 1/4 of the total root zone. Most of the important feeder roots of trees or shrubs are within the upper six inches of the soil and if damaged, uptake of water and nutrients is restricted reducing growth.

In addition, root damage may take months or even years to progress, and it is during this period where problems begin which can cause symptoms of decline or demise depending on the situation and how much damage occurred.

One of the biggest problems when root pruning bonsai is the lack of care taken, we have witnessed countless instances where the root ball is attacked with 2, 3, and 4 pronged instruments. The roots are basically ripped apart causing irreparable damage and as stated if more than 1/4 of the total root ball is damaged chances are that the tree’s health will diminish for some considerable time and this is where pests and disease can attack.

This brief discussion on germination and in particular the functionality of a plant’s root system may lead to a better understanding of its importance. But there are many other factors to consider, these include the wrong type of soil medium, incorrect pH (see article 06 ‘Soil Biology 1.’

Over and under watering, inferior lighting conditions, climate, stress, and worst of all the hidden menace. Which are pests and disease either within the soil medium, meaning fungal or insect attack above the soil level. (see article 26 ‘Plant Husbandry 1.’

A final thought on the root system especially with bonsai is root protection. Bonsai are confined to shallow pots and are vulnerable to extreme cold conditions. Any moisture in the soil will freeze preventing the root system from functioning properly to the point of demise. Therefore, some form of protection is required because in winter time trees still need water.

Of course much depends on the species, hardy species from colder climes do not need protection as they are endemic to the region and are used to extreme conditions. But species from temperate zones will not, our experiments using the Aleppo pine Pinus halepensis, native to the Mediterranean region as an example proved our theory to be correct.

Nonetheless, if in doubt take precautions and move vulnerable trees to cold storage. In the next article on ‘Plant husbandry’ we turn our attention what happens above the soil, until next time, BW, Nik.

Hi, welcome to Taiga Bonzai in this article we discuss some of the many reasons why plants give the appearance of health and vitality one moment, then suddenly show signs of decline. A problem scientists and horticulturists have been trying to solve for eons.

Introduction – there are countless reasons why plants die and to attempt to explain the cause and effect would result in volumes of the written word. Therefore, we look at some of the most common and uncommon. These include the seed or plant, soil medium, water table, pests and disease.

It can be argued that seeds are delicate in their form and their is evidence to support this theory for example. In (commercially grown) vegetables and various fruit species, due to their short ‘shelf life’.

However in the main seeds collected from the wild are robust and hardy, able to withstand high and low temperatures. They can be stored in the right conditions for long periods of time; providing they have not been attacked by pests and disease.

Soil mediums – are prepared to suit the plant be it ericaceous (coniferous) or organic. (deciduous) It should be a composition with good drainage allowing the roots especially feeders to travel in search of nutrients and moisture. (see article 06 – ‘The pH factor (Part I)’ which discusses the acidity/alkaline levels for a range of plants.

A question often asked is “does the soil have to changed on a regular basis” in short the answer is no. Because a teaspoon of soil is estimated to contain up to a billion bacteria cells, that work to maintain the soil condition. Adding a small amount of fertilizer occasionally helps and the plant can survive for years in the same medium.

However, much depends on the type of plant regardless of the species. If growing from seed then the plant will require a soil medium to help the initial growth stage for example, John Innes no. 1 or similar brand.

When the plant has developed sufficiently i.e. a few pairs of true leaves it is re-planted in a soil medium that is more appropriate. This is done to slow the growth rate, otherwise the plant/s become ‘spindly’ tall, or thin. Hence, the result is usually stress and vulnerability to attack because it’s defences have yet to be developed.

Water table – in the main most trees dislike their roots soaking wet nonetheless, there are exceptions to this consensus for example, the following permanently reside in wet conditions.

Pumpkin genus Cucurbita, Ash, Fraxinus profunda Sweetbay Magnolia, Magnolia virginiana Willow, Salix Mangrove, Rhizophora mangle Bald Cypress, Taxodium distichum Water Tupelo, Nyssa aquatica River Birch, Betula nigra and Pin Oak Quercus palustris. The water pH ranges from acidic to saline and plants living in such conditions are able to thrive. Whereas other species cannot tolerate these extremes.

Rain water is always preferable, alternatively if you rely on the household tap, the water condition will depend on the supplier and the chemicals used to treat it for example. Chlorine (CI) a strong disinfectant added to drinking water as a purification technique. Moreover, tap water needs to stand for a couple of days before use.

Pests and disease – the most common of pests and disease derive from insects including: Aphids Aphidoidea, Scale Coccoidea, Mealybug Pseudococcidae, Sawfly Septentrionalis and Red spider mite Tetranychus urticae. The latter difficult to see with the naked eye as it resides in the soil, the only immediate way of detection is via the very fine webs they weave.

The above mentioned pest are just an example and can be dealt with accordingly using horticultural soap not insecticide. Unfortunately the predators that usually protect our plants are disappearing at breakneck speed due to loss of habitat caused by the idiosyncratic lust for urbanisation.

The decline – over the last few decades there has been a decline in the insect population. Disappearing are many helpful predators including, Ladybugs Coccinellidae, Green Lacewings Chrysopidae, Honey Bees genus Apis, Praying Mantis family Mantidae, Spiders family Arachnida, Ground Beetles family Carabidae, Soldier Beetles family Cantharidae, Assassin Bugs family Reduviidae and Robber Flies. Asilidae

These insects are part of the food chain they eradicate unwanted pests including aphids, scale, mealy bugs and saw fly and in turn are the main resources for many birds, small mammals, fish, reptiles and other creatures.

Moreover, they are an important key for human food production because, many crops depend on insects for pollination leading to fruit and seed production. Insects play a very important role in decomposing organic matter allowing nutrients to return to the soil. Therefore, in terms of insect ecological importance, a sharp decline in their abundance is of great concern.

The arguments – here are the points view from others whom are mindful of this issue. Will de Freitas asks if we are facing insect Armageddon he states that, “A recent study found that German nature reserves have seen a 75% reduction in flying insects over the last 27 years.”

The researchers involved made stark warnings that this indicated a wider collapse of the general insect population that would bring about an ecological catastrophe if left unchecked. (article – October 25, 2017 – The Conversation)

Damian Carrington Environment editor for ‘The Guardian’ in his article (10th February 2019) argues that “The world’s insects are hurtling down the path to extinction, threatening a catastrophic collapse of nature’s ecosystems.” “More than 40% of insect species are declining and a third are endangered. “The rate of extinction is eight times faster than that of mammals, birds and reptiles; the total mass of insects is falling by a precipitous 2.5% a year, according to the best data available.”

In the February 2020 journal ‘Biological Conservation’ no, 242 (a leading international body of scientists in the discipline of conservation science) Editor in chief Vincent Devictor of the Institut des Sciences de L’Evolution de Montpellier, France stated that.

“We are causing insect extinctions by driving habitat loss, degradation, and fragmentation, use of polluting and harmful substances, the spread of invasive species, global climate change, direct over exploitation and co-extinction of species dependent on other species.”

Devictor goes on to say that “With insect extinctions, we lose much more than species. We lose abundance and biomass of insects, diversity across space and time with consequent homogenisation, large parts of the tree of life, unique ecological functions and traits and fundamental parts of extensive networks of biotic interactions. “Such losses lead to the decline of key ecosystem services on which humanity depends.”

The blame game – these are but a few of the arguments from scientists and conservationists from the many we have researched and from these points of view, it appears we have a major situation on our hands.

There are many theories as to the decline in insect populations they include, habitat destruction by intensive farming and urbanisation, pesticide use, introduced species, climate change, eutrophication from fertilisers, pollution and artificial lighting; the latter used in huge polyethylene tunnels for intensive crop production.

Yet, despite the scientific evidence provided, globally our performance in instigating effective insect conservation is below par, we need to realise this fact and act accordingly.

This would involve more inclusive education, better decisions with land managers and government officials in maintaining unique habitats, across the globe. To have more expansive sustainable agriculture and forestry, improved regulation and prevention of environmental risks and greater recognition of protected landscapes.

Insects are a major component of the tapestry of life and failure to protect them will have dire consequences. Because without them a void will appear allowing unwanted pests to multiply to plague proportions.

As we go through our discussions on ‘Plant husbandry’, we reveal more facts that have disastrous effects on horticulture including bonsai. Until next time, BW, Nik.

Hi, welcome to Taiga Bonsai, in this article we continue our discussion on ‘Plant husbandry’ dealing with more harmful pests and disease.

Introduction – during World War II (1939 – 1945) many governments mandated that more produce be grown to feed those at the front line and rationing was introduced which lasted until 1954. Meadows and wildlife havens were turned into arable land and although the effects of this were not apparent at the time; it was the beginning of the end for the bug world.

The birth of the EEC – on March 25th, 1957 France, West Germany, Italy, the Netherlands, Belgium and Luxembourg signed the Rome treaty establishing the European Economic Community (EEC), also known as the Common Market. Later other countries joined and soon there was an abundance of food.

This excess including butter mountains, milk and wine lakes, gluts of potatoes, apples and other crops could have been given away to the poor, or countries facing drought and famine. Instead what could not be poured away was disposed of in disused mine shafts. The politicians and agricultural heads wanted to maintain ‘economic stability’ – ‘nothing is for free’.

The green and pleasant lands are now a bygone era, forests have and are being cut down. An area the size of Wales 20,779 km² (a country in southwest UK) is being removed on a daily basis in the Amazon.

The meadows that existed are now under housing estates, rivers are polluted and the air quality is deteriorating. The friendly bugs have gone and it is doubtful they will return. The crop harvests GMO or organic will devastated by marauding invaders many whom are immune to pest control.

A never ending battle – according to CABI News digital library (09 February 2022) they conclude there are approximately 73,000 different tree species on Earth, of which around 9,000 are thought to be undiscovered. In addition, there exist more than 80,000 known plant diseases worldwide.

All plants are vulnerable to attack by disease, including crop plants which are frequent victims. The result is enormous agricultural, horticultural and economic loss. Now due to the relaxed regulations pest and disease are able to infect countries that were free of this devastation.  

The problem with disease – is that it cannot in reality be detected until there is visible evidence, by insect damage or that of fungi. Science has told us that microorganisms can exist in a single-cell form or a colony like bacteria and fungi. Although they are often associated with dirt and disease, most microbes are beneficial. But as we are aware there exist those microbes, fungi and pathogens that have lethal potential; here a few examples.

Armillaria mellea is a parasitic fungus doing immense damage to forests, it attacks both coniferous and deciduous species. By the time the fruit bodies are in evidence, the damage done internally is usually so great that the tree is doomed.

It is widespread in northern temperate zones including North America, Europe, Northern Asia and in South Africa. Trees that are attacked become parasitized. The foliage becomes sparse and discoloured, twig growth slows down and branches die back. There are no known fungicides or management practices that can kill Armillaria mellea after infection without damaging the infected plant.

Canker is a small area of dead tissue, which grows slowly, some of these are of only minor consequence, but others are ultimately lethal and therefore, can have major economic implications for agriculture and horticulture.

They are caused by a wide range of organisms including fungi, bacteria, mycoplasmas and viruses. The majority of canker-causing organisms are bound to a unique host species or genus, but a few will attack other plants. Fungicides or bactericides can treat some cankers, often the only available treatment is to destroy the infected plant to contain the disease. The Butternut canker (shown below) is a lethal disease affecting Butternut trees for which there is no cure.

This is a deadly bacteria that attacks economically important crops such as olive, citrus, plum trees and grapevines. Since 2015, it’s been rapidly spreading from the Americas to Europe and Asia. Once the disease infiltrates a plant, it is there to stay, it starves the plant of water until the plant dies or becomes too weak to grow fruit. 

Xylella fastidiosa – is another deadly disease the bacterium (shown below)

X. fastidiosa costs $104 million per year in wine losses in California and in Italy. The bacteria has led to the decline of 180,000 hectares of olive groves destroying many centuries-old trees; a loss of €390 million over three years. X. fastidiosa constitutes a threat not only to Italy but to all the Mediterranean region’s economy.

X. fastidiosa is not known to be in the UK however, there have been outbreaks of the disease in mainland Europe in France, Italy and Spain. Portugal confirmed its first case in 2019 on lavender.

The UK Government is concerned about how to prevent the disease being accidentally brought into the country on imported plants. In 2020 Lord Framlingham a Conservative peer asked the Government what the UK’s regulations are regarding X. fastidiosa.

UK regulations were to introduce measures to strengthen the protection of plants from certain pests and diseases, including Xylella. They were made under article 52 of the EU Plant Health Regulation, allowing the UK to take additional temporary national measures. Providing they inform the European Commission and put forward a technical case to request EU measures against a specific pest.

However, those measures have not or will not be introduced in time to mitigate the risk concerned. Moreover, the UK Government has argued that current EU emergency measures on Xylella, do not address risks highlighted in the UK’s pest risk analysis on the disease.

In particular, it is not clear if or when the EU emergency measures will be reviewed to address these risks and ensure a greater degree of assurance of disease freedom, in relation to plants of those species being moved in the EU and introduced from third countries.

As such, there remains an unacceptable level of pest risk and this instrument introduces national measures under article 52, in the absence of EU requirements.

Verticillium– is a genus of fungi in the division Ascomycota, which is an anamorphic form of the family Plectosphaerellaceae. The genus used to include diverse groups comprising saprobes and parasites of higher plants, insects, nematodes, mollusc eggs and other fungi.

The genus, currently thought to contain 51 species, may broadly be divided into three ecologically based groups – mycopathogens, entomopathogens, plant pathogens and related saprotrophs. At least five species are known to cause a wilt disease in plants called verticillium wilt: V. dahliae, V. longisporum, V. albo-atrum, V. nubilum, and V. tricorpus. A sixth species, V. theobromae, causes fruit or crown rot, a non-wilting disease.

Verticillium wilt is a disease that can affect over 400 different plants and trees, many of which are economically important worldwide. Several characteristics of Verticillium make it difficult to manage: prolonged survival in soils without the presence of a host plant.

The fungus survives in the soil principally in the form of microsclerotia and invades the plant through the root system, colonising the vasculature eventually leading to plants demise.

The main mechanisms of it’s pathogenesis are xylem vessel blockage and toxin production. When the fungus propagates within a host plant, the mycelium blocks the xylem vessels, impairing the transport of water and nutrients in the host.

Thus forces of transpiration and respiration in leaves combined with blocked xylem transport, cause water imbalances in leaves that result in leaf yellowing and wilting, contributing to plant death.

In addition, Verticillium produces mycotoxins within the plant that can cause necrosis in leaves and impair metabolism in the plant’s body. In some systems, toxin production has been shown to be the main cause of plant wilting.

The diseases discussed here (Armillaria mellea, Butternut canker, Xylella fastidiosa and Verticillium) are very serious not to be taken lightly, they can infect other plant types within the vicinity. However, there are many more to be found within the 80,000 diseases that we know of. In the next article we look at the borers, until next time, BW, Nik.

Hi, welcome to Taiga Bonsai, in this article we discuss some of the insects that are devastating both agriculture and horticulture.

Introduction – borers are perhaps the most harmful to trees, they originate from many countries causing great damage to native species that have no defence. How they were introduced to the western hemisphere is predominantly via wooden packaging.

The Asian Longhorned beetle – Anoplophora glabripennis native to eastern China, and Korea has been introduced into the United States, where it was first discovered in 1996, and in Canada and several countries in Europe including, Austria, France, Germany, Italy and UK.

A. glabripennis primarily infest maple, poplar, willow, and elm trees. In the United States it has attacked birch, katsura, ash, planes and Sorbus. In Canada on maple, birch, poplar, willow and in Europe on maple, alder, birch, hornbeam, beech, ash, planes, poplar, Prunus, willow and Sorbus.

The Bronze Birch borer – Agrilus anxius a wood-boring buprestid beetle native to North America, numerous in warmer parts of the continent where it thrives. It is a serious pest on birch trees Betula frequently killing them. If this insect came to Europe there would be no hope for Birch forests, as the trees have no resistance against this species of insect. Hence the effect on Scandinavia’s Birch industry would be devastating.

The Emerald Ash Borer Agrilus planipennis, a devastating alien pest of ash trees was first detected in Europe and in Moscow in 2003. Its outbreak in the cities of Europe and Russia seriously damaged plantations of Ash trees Fraxinus pennsylvanica. It was introduced from North America.

This alien pest posing a major threat to ash trees all over Europe has spread to Ukraine and the south of Europe severely damaging the green ash F. pennsylvanica. Research indicates that will appear in other European countries soon with the potential to destroy F. pennsylvanica plantations.

The Chinese emerald ash borer found its way to America via international shipping, when it gained its freedom. It was greeted with a fresh new smorgasbord of North American ash trees Fraxinus americana, thus making itself a new home in which to reside. To date the amount of devastation to millions of ash trees is now in the tens of millions across 25 states.

Airborne invasion – we know that many pests and disease have migrated throughout the world by conventional methods. In packaging containing merchandise and sometimes in the merchandise itself. Mainly via land sea and air.

However, these modes of transportation is not the only way for pests and disease to migrate to other realms. There are those whom are able to take to the wing and reach altitudes of 2,000m some actually fly, whilst other drift on the air currents.

For example, the Desert Locust Schistocerca gregaria a periodically swarming, short-horned grasshopper from Africa, destroys thousands of hectares of crops on its migration eastwards. These pests can easily reach and altitude of 2,000ms and cover a distance of up to 200 km in a single day.

Those that tend to drift on the air currents and travel vast distances include pathogens that are microscopic, the average size of most bacteria is between 0.2 and 2.0 micrometre, (diameter). Fungal spores typically range in size from 2 to 50 μm in diameter, with most allergenic spores in the respirable size range of 3 to 10 μm.

Such pathogens when earthbound are able to create their own colonies if conditions allow. They can attack vulnerable vegetation including food crops, flowering/fruiting plants and trees. At this juncture methods of control are inadequate. The old adage that ‘Prevention is better than cure’ is meaningful, but the devastation of these ‘unseen enemies’ only becomes visible when it is too late to react.

Sirex wood wasp Sirex noctilio a species of horntail native to Europe, Asia, and North Africa. Is an invasive species in other realms including Australia, New Zealand, North and South America and South Africa, where it has become a significant economic pest of pine trees especially Pinus radiata.

The wasp can attack a wide variety of pine species, although some species seem to be more susceptible than others and stressed trees often are attacked. It is believed that this insect was introduced on unprocessed pine logs imported from Europe.

P. radiata were first planted in the late nineteenth century in Australia, Chile, New Zealand and in South Africa during the early 1900’s. Their excellent growth provided the basis for thriving lumber and paper industries.

During 1920’s and 30’s the lumber industry stagnated because the demand for small logs from thinning operations decreased. This made plantations susceptible to S. noctilio and its associated fungus, Amylostereum areolatum. By 1947, high levels of tree mortality were occurring, primarily in the un-thinned plantations causing devastation to the lumber and paper industries.

Adult sirex wood wasps vary in size from 9 to 36 mm (0.35 to 1.42 in), during oviposition the female will lays 2 eggs often with a mucoid substance and a symbiotic fungus to feed on once hatched. This mucoid substance is toxic to trees as are the ascospores from symbiotic fungus Amylostereum areolatum. A species of crust fungus originally called Thelephora areolata, it was given its current name by French mycologist Jacques Boidin in 1958.

The hidden menace – Dutch elm disease (DED) first appeared in the north-west of Europe about 1910. Between 1914 and 1919, several Dutch scientists carried out influential research on the cause of the disease. According to https://www.forestresearch.gov.uk this disease “Is one of the most serious tree diseases in the world.”

The fungus that causes the disease is spread by bark beetles triggering foliage and tip dieback in all of Britain’s native elms. Including the English elm Ulmus procera, smooth-leaved elm U. carpinifolia and wych elm U. glabra. The disease first spread to Britain in the 1920s, where it killed 10-40% of elm trees. Although the initial epidemic died down, a more aggressive species of Dutch elm disease fungus was accidentally introduced into Britain in the 1960s.

A second epidemic took hold of lowland central and southern Britain where there were English elms in the early to mid-1970s and by 1980. Most mature English elms had died. Although scattered pockets of mature elm occasionally survived, where the geographic situation has facilitated an effective and continuing sanitation control program.

By the late 1980s the bark beetles used up most of the mature elms that they relied on for breeding material. Hence beetle populations declined and the disease virtually disappeared from many southern and south-western areas.

In 1982, Forestry Commission research on the biology of Ophiostoma novo-ulmi, an extremely virulent species from Japan has devastated elms in Europe, North America, Asia and now is spreading across across Eastern Europe. (Romania to Poland)

This suggested that the disease would not decline in intensity or contrast to the first epidemic, caused by O. ulmi. The new pathogen, O. novo-ulmi, would return in a continuing cycle to attack the following generation of small elms once they were large enough to support beetle breeding.

Cryphonectria parasitica a pathogenic fungus a member of the Ascomycota (sac fungi) native to East Asia and south-east Asia. It was introduced into Europe and North America in the early 1900s spreading rapidly causing significant tree loss in both regions.

This disease came to be known as ‘chestnut blight’ due its infestation of Chestnut trees Castanea dentata and has had a devastating economic and social impact on communities in the eastern United States.

Once a tree begins to decline it is often dead within a few years and eradication efforts by cutting and burning the infected plants/trees have mostly failed; at this present juncture there are no chemical management options for control.

Thus far the consequences of mankind’s actions over the millennia do not paint a good picture. In fact the problems we have tried to solve many of which we cannot are only increasing at an alarming rate.

As stated there are no chemical management options for control, should we concentrate our efforts to find more potent solutions to eradicate pests and disease; we have already tried this approach with negative consequences. Until next time, BW, Nik.

Hi welcome to Taiga Bonzai, in this article we attempt to answer some of the questions that continue to perplex the most learned concerning the demise of flora. In many cases the answer is given in a reasonably short time frame, but there are instances where no definitive explanation can be agreed upon.

Introduction – with the planet constantly evolving evidence exists of events that have resulted, some have been of minor consequence whilst others have caused complete devastation for example.

In 1954, a swarm of locusts Schistocerca gregaria invaded Kenya covering an area of 200km². The estimated density was 50 million individuals per km², a total number of 10 billion locusts in that swarm. This caused a major catastrophe in the loss of crops resulting in a famine situation. Today not much has changed Africa still suffers from this onslaught.

Life expectancy – nothing on this planet lasts forever, all flora, fauna including humanoids have a life expectancy and nothing can change this phenomenon. Even planet Earth has a life expectancy, a subject for another time as the implications associated would make this article far too long. Nonetheless, for those of a inquisitive nature we point you to the NEW ATLAS and their scientific author Michael Irving, who wrote an article on this subject in March 01 2021. Link below.

https://newatlas.com/environment/earth-atmosphere-oxygen-life-expectancy/

Humanoids and fauna – it can be argued that a debate on these two species would make for interesting discussion and much has been written by notable academics. Including, Alfred Russel Wallace and Charles Robert Darwin, works include; The Descent of Man and Selection in Relation to Sex (1871), The Expression of the Emotions in Man and Animals (1872).

Flora – all humans especially government officials are responsible for the planet’s well being concerning plant life regardless of the scale. Pests and disease transmitted by our actions either knowingly or not have been in existence for thousands of years.

We have discussed this topic at length including the deadly disease Xylella fastidiosa, first discovered by plant pathologist Newton Pierce in 1892. A disease that is an aerobic, Gram-negative bacterium of the monotypic genus Xylella. This plant pathogen is transmitted exclusively by xylem fluid-feeding sap insects. 

There is no chemical control for X. fastidiosa as is the case for many pests and disease. Infected plants are destroyed to prevent the disease spreading further. Resulting in a loss of crop production costing vast sums of revenue to the tune of billions.

Although many countries are deeply concerned, they just cannot find common ground to find a solution to the problem. Yet they whine, moan and sabre rattle on unimportant trivial items, hence it is difficult to comprehend their logic and justification for such.

The enemy – most common plant pathogens are fungi, bacteria, mollicutes, parasitic higher plants, parasitic green algae, nematodes, protozoa, viruses, and viroids. Here is a brief description on these and their functionality should you encounter them.

Fungi – many people believe fungi are plants, this a misnomer they are neither plants nor animals, but organisms that form their own kingdom of life. The way they feed themselves is different from other organisms, they do not photosynthesize like plants nor do they ingest their food like animals.

Fungi can be deadly poisonous as in the ‘Death cap’ Amanita phalloides variety and is the world’s most toxic mushroom. It contains alpha-amanitin which is responsible for causing liver and kidney failure.

Bacteria – are both beneficial and pathogenic, beneficial bacteria are involved in such diverse processes as digestion in animals. Nitrogen fixation in the roots of certain legumes and the decomposition of animal and plant remains and sewage disposal systems.

Pathogenic bacteria called fastidious vascular bacteria grow in either the xylem or phloem tissues. They interfere with the transport of water and nutrients in the plant, vectored by sucking insects such as leafhoppers, planthoppers and psyllids.

Mollicutes – are parasites in the class of bacteria distinguished by the absence of a cell wall. The word ‘Mollicutes’ is derived from the Latin mollis and cutis. Individuals are very small, typically only 0.2–0.3 μm in size and have a very small genome size. The best-known genus in the Mollicutes is Mycoplasma colonies which show the typical ‘fried-egg’ appearance. (shown below)

Parasitic higher plants and Green algae – hemiparasites often referred to as water parasites, do injure their host plants, absorbing water and mineral nutrients from them. They possess chlorophyll and can manufacture their own carbohydrates by photosynthesis.

Green algae are a foliar disease most commonly seen in warmer climates or in greenhouses. The main organism is Cephaleuros virescens, a green parasitic alga whose usual hosts are plants with leathery leaves such as litchi, magnolias, hollies, rhododendrons and viburnums.

Nematodes – often called ’roundworms’ are the most numerous multicellular animals on earth. A handful of soil can contain thousands of the microscopic worms many of them parasites of insects, plants or animals. Free-living species are abundant, including nematodes that feed on bacteria fungi and other nematodes. There are nearly 20,000 described species classified in the phylum Nemata many of which are associated with disease.  
 

Protozoa – are a group of single-celled eukaryotes either free-living, or parasitic that feed on organic matter such as other microorganisms or organic tissues and debris. They come in many different shapes and sizes ranging from an Amoeba which can change its shape to Paramecium with its fixed shape and complex structure. Some are parasitic meaning they live in other plants and animals including humans where they cause disease. 

Viruses, and viroids – viruses are a submicroscopic infectious agent that replicates only inside the living cells of an organism. They infect all life forms from animals, plants and other microorganisms, including bacteria and archaea. Viroids are infectious pathogens, they are small single-stranded, circular RNAs. Unlike viruses, they have no protein coating, all known viroids are inhabitants of angiosperms (flowering plants) and most cause disease.

The hidden menace – is an undetected problem that remains hidden until it becomes visible, mainly caused by either insect damage, or that of fungi and canker. Signs are usually browning of the leaves or loss of leaf drop due to chlorosis and white fungus caused by Verticillium wilt sp., for which there is no effective treatment.

Verticillium wilt can lie dormant until the conditions are such that is activated, it can spread rapidly. There are various strains of this fungal disease including, (Verticillium albo-atrum, Verticillium dahliae), Fusariosis (Fusarium sp.) and decay caused by fungi from the genera Phytium, Alternaria and Botrytis. 

In the next post we continue this discussion as it is an important factor for the well being of plants. More information made public via written text can only be beneficial to those dealing with horticulture including bonsai. Until next time, BW, Nik.

Hi welcome to Taiga Bonzai, we continue our discussion on pests and disease as it is an important topic that effects all aspects in the world of flora including bonsai.

Introduction – being mindful of the pests and disease affecting horticulture, especially temperate species which are vulnerable.

All flora are susceptible to attack from pests and diseases whether grown naturally or cultivated. In an attempt to eradicate these unwanted problems most fruiting and flowering specimens are sprayed with a fungicide or repellent.

Chemical protection – does in many respects produce the results intended, but some will argue that it also destroys those creatures that eradicate the unwanted. Moreover, it can be said that when winter arrives many pests will die due to loss of foliage and the coming cold.

Nonetheless, there are such pests whom are able to survive cold conditions via hibernation hidden beneath a tree’s bark, in it’s seed pods or in the soil medium.

For example, the Oak – genus Quercus, a favourite of the Tortricid Moth caterpillar – Family Tortricidae that destroys acorns. Carpenter Ants – Genus Camponotus hibernates under pine tree bark. The spruce beetle, Dendroctonus rufipennis its larvae bores into the phloem of conifers and feeds on the live tissue.

The Asian longhorn beetle Anoplophora glabripennis a native of China and the Korean peninsula excavates 1cm diameter holes in the main trunk causing sap bleeding. Eventually the affected tree dies.

Diseases – include; ‘Red band needle blight’ Dothistroma, needle blight affects conifers most commonly pines. It causes needle loss, which eventually kills the tree. Ash die-back Fraxinus excelsior affects ash trees it is caused by the fungus Hymenoscyphus fraxineus, that blocks the tree’s water transport system causing leaf loss and ultimately die-back of the tree’s apex or crown.

Horse chestnut canker a bacterium species known as Pseudomonas syringae pv. Aesculi. It causes extensive bleeding areas on tree stems. Phytophthora austrocedri affects junipers causing die-back of foliage, stem and collar lesions and eventually death.

The above mentioned pests and diseases are but a few of the 80,000 that we know of, attacking many species of tree both deciduous and coniferous. Arguably such devastation is due to climate change and infestation via unwanted importation of packaging material. For example wooden boxes and crates and although authorities do much to enforce regulations, it is difficult to stem the invasion.

We like to assume that our indoor environment is free from pests and disease, nothing could be further from the truth. The ‘greenhouse’ or home is riddled with invaders and no matter how vigilant we are, eradication is virtually impossible.

Arguably, the cause why the latter are able to thrive is due to the temperate conditions plus abundance of food and water. Here are a few of the most common that devastate plant life.

Mealybugs – quite visible to the naked eye are related to scale insects and congregate on leaf joints and the undersides of leaves. They damage plants by sap sucking, which causes the leaves to wilt, turn yellow to brown and eventually fall from the plant. Removal of this pest(s) can be achieved either by spraying them with water or via a chemical spray designed for Aphid treatment. The plant then should be isolated from others until the treatment is successful and the plant has recovered.

Aphids – normally a pale green in colour can be found in other shades such as grey and black. Having arrived on a plant their numbers rapidly increase infesting the plant in great hordes with a preference for the underside of leaves. As with the Mealy bug they also suck the sap from the leaves and if not removed quickly, the plant may become infected by disease and viruses.

Aphids can be removed relatively easily by the use of warm soapy water directly sprayed on them. Alternatively a chemical application designed for this pest can be used, but the plant should be isolated until the treatment is completed and the plant is free from infection.

Scale Insect – there are more than 25 species of these limpet-like creatures, which makes identification difficult due to their well camouflaged appearance. They devastate a wide variety of plants by sucking the sap and as a result the plant is severely weakened distorting growth.

Evidence of their existence can be seen as the growth of black, sooty moulds and or a sticky substance (honeydew) on foliage. Another sign of scale infestation is leaf blemish. Scales have hard shells and removal can be difficult hence the use of chemical application such as an Aphid spray, which softens the shell eventually killing them. The plant has to be isolated until the treatment is successful.

Sawfly Craesus septentrionalis – can be a real nuisance for those whom have Betula species (Birch) as bonsai specimens because, the tender young leaves are prone to be ravaged by the Sawfly larvae running rampant all over the tree. As do the larvae of a large number of species of butterflies, moths and other insects. Female sawflies are so called because of the saw-like appendage at the tip of their bodies, which is used to cut slits into the leaves where the eggs are laid.

There are different species of sawfly and the damage cause by their larvae is peculiar to each species for example. Some will leave notches or holes in leaves or devour the leaf leaving just its skeleton, others spin webs, leave galls and some will roll up a leaf completely.

Sawfly are commonly found in bonsai for example. Conifer sawflies feed on needles and bore into buds and shoots. On Salix (Willow) the sawfly leaves distinctive red/brown galls, fruit and flowering – Prunus,(Cherry) Pyrus, (Pear) and Malus (Apple) are all affected by the sawfly.

The most common way to eradicate sawfly larvae is either removal manually or by using a horticultural soap as used for Aphids and Mealybugs, but the plant should be isolated so as not to infect others and to allow for the treatment to work.

Sciarid flies – often called Dark-winged fungus gnats – are commonly found in moist environments including areas where house plants are situated. They thrive on damp soil conditions and can be seen scurrying over the soil, flying around and landing on stems, branches and leaves. Although they are known to be a pest in mushroom horticulture, they present no threat to bonsai plants nonetheless, they can be extremely irritating especially in a home environment.

This large Diptera genus is one of the least studied mainly due to its small size 2mm and the difficulty in specific identification. It is said that more than 1,700 species have been described with an estimated 20,000 awaiting further study.

Springtails – Collembola form the largest of the three lineages of modern hexapods the other two being Protura and Diplura these creatures are not classed as insects, because they are omnivores having internal mouth parts.

They are small white or grey in colour and feed off the soil’s dead organic matter. When plants are watered and springtails are present, they are agitated and move rapidly and look unsightly. Springtails pose no threat to bonsai or other house plants, it is their very presence which can be irritating.

If the desire is to eradicate these creatures, one can water the plants from the bottom by immersing the container in water and/or reduce the amount of water. But water reduction may not be conducive to some plant species, hence a careful balance should be maintained.

The above mentioned pests and diseases are common to bonsai horticulture, they are but a few of the many thousands that are in existence. Nevertheless, over the past decades horticulturists and scientists have done much of the spade-work, hence it is not that difficult to find the answer one is looking for a particular problem. But it pays to be vigilant and inspect your bonsai specimens on a regular basis; ‘Prevention is better than cure’.

Soil – another factor to consider is the soil composition, because bonsai are confined to a relatively small quantity of soil and this growing medium has to fulfil its needs. It must be able to retain water yet have good drainage and have the ability to allow for air circulation.

Soil contains a multitude of living organisms that consume, digest, and cycle nutrients. These living organisms include archaea, bacteria, actinomycetes, fungi, algae, protozoa, and a wide range of insects for example. Mites, nematodes, earthworms and ants, all of which are important to the vitality of a soil composition.

Soil in a bonsai pot does not last indefinitely, it decays over a period of time due to the absorption of minerals therein and once expired it is unable to support the tree in order to sustain health and growth. This is when the tree is most vulnerable and attack from pests and disease can quickly take hold.

Having said this one may think that a bonsai has to be re-potted every year – not only is this a misconception, it is unnecessary. A tree in a pot or container planted in year one will take at least 2 to 4 years to establish itself although much depends on the species and its growth rate.

This can be assessed by teasing the tree out from its container and checking the root ball. If the roots are densely packed with little soil in situ, then it will probably need re-potting. Alternatively if what is seen is the opposite, then it can be re-placed and left for another season or two. Until next time, BW, Nik.

Hi welcome to Taiga Bonzai, in this article we discuss bonsai pot design, colour, texture and functionality.

Introduction – a potential bonsai is a ‘living’ work of art and requires the correct pot because ‘Bon’ (pot) is the frame and ‘Sai’ (tree) is the picture or image. Both have to compliment each other in order to accentuate the overall composition.

Potential bonsai – specimens purchased from a store, garden centre, nursery or indeed other sources will need training to suit a particular design. This takes time, some species can take a few seasons to train whilst others much longer, but much depends on the intended design one is looking to create.

However, for some there is the urgency to purchase a ceramic pot/s be it lavish ‘hand made’ or mass produced. Buying bonsai pots purely for cosmetic values is a needles expense. Because the design of your tree may change over time, or it will out-grow the pot. A better way to lessen the expense is to buy plastic trainer pots or make boxes.

Boxes – a potential bonsai regardless of its origin needs space to grow, to develop its root system, trunk girth, branches and ramification. It cannot do this if restricted in an undersized pot. Our solution is to make boxes out of chemically free scrap wood for example, old pallets usually free from a builders or timber merchant.

The benefit of a box is that it gives plenty of room for ‘root-run’ establishing a strong and healthy root system needed for good Nebari. In addition, guy wires can be placed anywhere for stability and to aid in the tree’s design, which cannot be done if in a ceramic pot. The reason for this approach is that often conventional wiring cannot be achieved because of branch and trunk thickness.

Moreover, if undisturbed for example three years this will allow the tree to develop more quickly. In reality, a bonsai does not need a pot until it is at least 80% near to its final design. But knowing which pot to select is not as easy as it may seem, because a tree in the wrong pot can actually lessen the visual impact diminishing the tree’s full potential. A tree in the right pot will look quite remarkable.

Selecting the correct pot – then how do we find the right pot? Generally speaking, the accepted rule is that un-glazed pots are for conifers, whilst glazed pots are for deciduous. To arrive at a suitable conclusion when selecting a pot, there are some points to consider. These are the tree itself, pot shape, dimension, colour and texture.

Trees – a tree that gives an impression of strength through its large trunk and mature weather beaten nature, strong canopy can be considered as masculine and Pines are a good example of this.

Alternatively, a tree having a more delicate appearance via its trunk’s gentle taper and delicate foliage can be viewed as feminine, such examples of this are the ‘weeping silver birch’ Betula pendula and ‘Acer’ Acer palmatum.

However, some trees are able to project both masculine and feminine appearances for example. The Rowan Sorbus aucuparia with its bright red/orange berries may have good movement in its trunk. But it’s fine ramification at the apex can be considered to have both male and female attributes. Therefore, when selecting a pot one must consider both these characteristics.

Pot shape and dimension – are also considered to have masculine or feminine attributes for example. Deep pots with strong angular features are considered masculine whilst feminine pots are shallower with softer lines.

The following images illustrate this meaning, 1. a deep rectangle pot with strong robust corners gives the impression of strength, especially suited to Pines. Whereas 2. has delicate rounded lines suitable for flowering/fruiting trees such as Cherry or Quince. Alternatively, trees having wide canopies that may be considered neither masculine or feminine for example a Beech Fagus sylvatica, are best suited to a wider shallower pots 3.

Other factors considered appropriate are the dimensions of a pot in relation to it’s tree for example. The depth of the pot should equal the diameter of the trunk just above soil level. For rectangular and oval pots, the size should be approximately ⅔ the height of the tree. For round pots it should be about ⅓ the tree’s height.

The colour and texture – of a pot can be used to enhance a tree’s particular feature for example, an un-glazed brown pot can highlight the ‘craggy’ brown bark of a Pine Pinus sylvestris. A dark blue glazed pot could be used to emphasise the red berries on a Cotoneaster Cotoneaster frigidus. A green glazed pot would enhance the leaves on a Beech. Fagus sylvatica. From these examples we see how a pot’s colour can be used to depict a tree’s particular feature.

Pot texture – For masculine pots textured finishes are ideal as they enhance the wildness of a tree’s rugged appearance. However, some contend that a smooth textured unglazed brown pot is able to enhance the tree’s ruggedness even further. It is a matter of choice.

Pots with smooth finishes are more suited to feminine trees, because their glazing highlights the tree’s feminine attributes. For trees that are considered neither masculine nor feminine meaning neutral, should be in pots that enhance their best characteristics either glazed or un-glazed.

Nonetheless, one factor that is crucial when planting a tree in a pot is its position, meaning how it will look. In most cases all bonsai apart from cascades styles are seldom positioned in the centre of the pot. They are positioned slightly to one side in order to achieve visual perspective and correct alignment. The illustration given below explains the importance of this.

We hope that this brief discussion on bonsai pots and their functionality is useful to our readers. In the next post we discuss the defensive system of trees and shrubs, until next time, BW, Nik.

Hi welcome to Taiga Bonzai, in the next few articles we discuss a selection of tree and shrub species used in bonsai that have defence mechanisms. Some are relatively harmless, whilst other are potentially lethal.

Introduction – in the early days of bonsai horticulture tree varieties included varieties of Juniper Juniperus Sp – Spruce Picea Sp – Pine Pinus Sp – Larch Larix and Acer Sapindaceae. As these were endemic to the various regions of China and Japan.

As time progressed, more species were added including flower and fruiting varieties. For example, Wisteria Floribunda and Azalea genus Rhododendron, Plum, Cherry, Peach and Apricot genus Prunus.

Many bonsai enthusiasts either have traditional collections predominantly coniferous, whilst others prefer deciduous and some will have an assortment of species. These artistically shaped miniature trees portray delicate, graceful and rugged forms and although their beauty is beholding; all is not what it seems.

These little adaptations are able to produce toxins just as their full-sized counter parts can, which have the power to incapacitate all fauna including humans with devastating results.

There are countless species of flora that exist on the planet including wild or natural varieties and hybrids. The latter pioneered by Gregor Mendel, whom is credited with starting the hybrid plant revolution with his genetic studies of peas in the early 1900s. And least we forget those that have been genetically modified to produce more flower and fruit and combat insect infestation.

All flora have developed ways to defend themselves. Via the production of toxins in their sap, leaves, fruit and seeds, to the emittance of gas, or extremely sharp toxic thorns which deter most from ravaging their foliage.

Today one can find many plant species that originate from other realms, many of which are now cultivated in the west. The list of trees and shrubs used in bonsai is quite extensive, we will describe some of the common and exotic in alphabetical order.

Acacia genus Acacia, of which there are approximately 160 species of trees and shrubs within the pea family Fabaceae, native to Africa and Australia. Those of the African savanna have an abundance of thorns for protection, but also use poison as a second line of defence.

When this species is disturbed it pumps poison into its leaves releasing ethylene gas from the pores. This gas release if detected by other acacias in near proximity sound the alarm alerting them to a potential threat. Hence, they too inject poison into their leaves. This information can be found in Sir David Attenborough’s book ‘The Private Life of Plants’ published in 1994.

Acer – family Aceraceae, the toxins are found within the leaves which increase as they wilt and die. It is also found in the seeds although the content is less. The acer although not harmful to domestic pets and humans is potentially fatal to equines if ingested. The poison damages red blood cells, diminishing their ability to carry oxygen. Death can occur from between 18 hours to 10 days.

Apple – Malus Spp., the seeds are mildly poisonous and contain a small amount of amygdalin a cyanogenic glycoside that play important roles in many plants including apple varieties. However, the amount of cyanogenic glycoside contained within the seed is not considered dangerous to humans. Nonetheless, ingesting a large quantity can provide severe side effects.

Alder Buckthorn – ‎Rhamnus frangula L., this tree or shrub found among hedgerows, along roadsides and in woodlands has a number of toxic chemicals. Of which, Emodin is the dominant one, found in the bark and purple-black berries or fruits. Emodin is a purgative resin, which is also found in rhubarb and also produced by many species of fungi. If ingested the symptoms are: collapse, convulsions, diarrhoea, gastroenteritis, haemorrhage and vomiting.

Azalea – genus Rhododendron Family Ericaceae is a common species that appear in bonsai collections but, it is poisonous. The toxins Grayanotoxin and arbutin glucoside are found in all parts of the plant the flowers, leaves and nectar – the latter often referred to as ‘mad honey’. They can cause nausea, vomiting, weakness, dizziness, breathing difficulties, low blood pressure, reduced heart rate and irregular rhythm, which could be life threatening.

Beech – genus Fagaceae, indigenous to Europe, Asia, and North America produce a triangular shaped fruit called beechnuts in the autumn. These nuts often used as a food source are high in tannins having a strong bitter taste and are toxic to both canines and humans especially children if consumed in large quantities.

The European beech Fagus sylvatica, is believed to be more toxic than its the American relative, Fagus grandifolia. Symptoms include; vomiting, diarrhoea, abdominal pain, nausea, fatigue and dilated pupils – mydriasis.

Birch – Betula Spp., has more homeopathic properties as opposed to toxins nevertheless, pollen from the silver birch, Betula pendula is the second most severe allergen for people. It can travel many kilometres via the wind. It is able to cause hay fever, conjunctivitis and severe respiratory problems with disease to the lungs and asthma. Severe cases of pollen infection do require medical attention.

Box – Buxus sempervirens, a common species found in bonsai collections is one to handle with caution as it is poisonous to humans. The leaves produce the alkaloid buxine which causes nausea, vomiting and diarrhoea and respiratory paralysis in humans and livestock. Contact with skin can cause irritable rashes and when pruning the clippings should be handled with care.

Cherry (Wild) – Prunus Spp., Wild Cherry trees produce fruit that are reddish black in the summer, which can be consumed. However, the wild cherry twigs and leaves contain the chemical Prunasin, a cyanide that when ingested, can be fatal. Prunasin breakdown and cyanide release occurs when the tree becomes stressed and an indication of this is when the leaves begin to wilt.

Chestnut (European horse) – Aesculus hippocastanum, is a large deciduous tree with greenish-yellow to white flowers and fruit contained in spiny capsules.

In the UK at autumn time children collect the fruit capsules and remove the seeds from within, thread them on lengths of string and participate in an old traditional game of ‘Conkers’. A game dating back to 1848 where turns are taken in striking each others ‘conker’ until one breaks; yet the players who take part in this ritual, are probably unaware that these ‘conkers’ or seeds are poisonous.

Cotoneaster – Cotoneaster Spp., are grown as bonsai mainly for their display of coloured berries ranging from bright orange to red to purple. This species is said to be a high risk in the toxicity range, because their leaves, berries and flowers all contain cyanogenic glycosides.

These toxins if ingested are converted to cyanide during digestion causing serious effect on the heart, liver, kidney and brain. For children the risk is higher than in adults, although much depends on the amount consumed.

Citrus – Citrus Spp., citrus oil is a concentrate of the fruit produced by the tree and also a protective barrier found on the leaves, which can be activated by a gentle rubbing with the fingers.

The scent of the oil is pleasant but the taste is bitter, leaving a nasty after taste due to Coumarin a fragrant organic chemical compound in the benzopyrone class. Although citrus oil is not harmful to humans, felines are more susceptible to citrus poisoning, which can result in diarrhoea, vomiting, liver damage or even death.

Douglas Fir – Pseudotsuga menziesii, a native of north America has smooth grey bark when young that are covered with numerous resin blisters, which should not be ingested. The leaves needle like in appearance have two whitish stomatal bands on their underside, that are pores to allow the exchange of gas.

If the leaves are damaged they emit a sweet fruity-resinous scent. Ingesting needles can result in vomiting, anorexia, abdominal pain, and lethargy. Other trees with similar attributes are: the Balsam Fir Abies balsamea, Blue Spruce Picea pungens, Red Spruce Picea rubens, White Spruce Picea glauca, Scots Pine Pinus sylvestris and Red Pine Pinus resinosa.    

Dogwood – Cornus Spp., a genus comprising of approximately 60 different varieties known for their brilliant floral displays in spring time. The fruits of many dogwood varieties are rather tart and unpalatable due to the amount of Tannins, but can be consumed if cooked.

However, fruit of the dogwood in the sub-genus Swida are toxic and should be avoided. Dogwoods are prone to attack by insects and fungal disease for example. Botryosphaeria Canker a dark yellowish pitch that oozes from dogwoods and Phytophthora a reddish orange sap oozing from the tree as a result of destroyed tissue. Dogwoods infected with this disease should be kept away from pets, children and other plants.

Dieffenbachia – family Araceae, a native from Mexico, West Indies and Argentina is widely cultivated as an ornamental houseplant and although not considered by some traditionalists as bonsai material, it is found in some collections.

Dieffenbachia is poisonous, it contains Raphides needle-shaped crystals of calcium oxalate. If the leaf or its residue is ingested it causes a burning sensation and erythema a redness of the skin or mucous membranes, caused by increased blood flow. Dieffenbachia can cause other symptoms including numbness, oral irritation and localized swelling.

Elder – Sambucus racemosa, is cited as a poisonous plant because the bark contains calcium oxalate crystals and the leaves and unripe fruits and seeds produce cyanoglycoside sambunigrin. But, ripened fruit when subjected to a cooking process reduces the toxins.

Elder suffers from Hyphodontia sambuci or Elder Whitewash a basidiomycete fungal pathogen forming a thin white, pruinose (flour-like dusting) on the limbs and branches. The pathogen should be avoided as the spores are easily carried by a gentle breeze.

Elm – Ulmus. has no toxins to speak of that are a danger to humans or domestic pets but its seeds, leaves and bark should not be ingested as a precaution. Because it is possible that the tree may be infected by Ascomycetes a pathogen relatively common to this species. Ascomycetes not only infest and destroy, they also produce secondary metabolites that are poisonous.

Eucalyptus – family Myrtaceae the leaves of this tree contain an oil that if treated and diluted can be safe for adult humans. But untreated oil is extremely toxic and ingesting a small amount (3.5 mL) can have fatal results.

Symptoms of eucalyptus poisoning may include stomach pain, a burning sensation, dizziness, muscle weakness, small eye pupils, suffocation, nausea, vomiting, and diarrhoea.

In toxic bonsai part II we continue the discussion on these trees and shrubs species, ‘letter’ ‘F ‘onwards, until then, BW, Nik.

Hi welcome to Taiga Bonzai, in this article we continue our discussion on a selection of tree and shrub species used in bonsai that have defence capabilities.

Introduction – as stated earlier horticultural enthusiasts be they bonsai enthusiasts or keepers of exotic plants, have various species in their collections. More often than not very little research is undertaken in understanding of what a particular plant has in it’s defence.

All plants are able to produce toxins that have the power to incapacitate all fauna including humans, but as to the level remains to be seen. We have mentioned alphabetically a few tree examples from ‘A’ to ‘E’, we continue with the letter ‘F’ onwards.

Ficus – family Moraceae. Is a genus of approximately 850 species that include trees, shrubs and vines collectively known as fig trees. Common species used in bonsai Ficus microcarpa and Ficus benjamina are quite popular especially as a beginners tree.

However, they are poisonous due to the milky white sap containing Furocoumarins psoralens and ficin that oozes out when pruned. This sap causes Dermatitis and allergic reactions for example, itching of eyes, coughing and wheezing, skin irritation with redness and stinging.

Forsythia – family Oleaceae (olive family) is also a popular choice in bonsai and there are eleven species predominately native to Asia. The species Forsythia suspensa is considered a major herb used in Chinese medicinal practices as it is non-toxic. But for safety reasons, one should not consume any part of the plant that is not edible.

Firethorn – family Rosaceae. A large shrub with sharp thorns related to the Cotoneaster (Cotoneaster is thornless). This a popular choice for bonsai due to its bright red and orange fruit that are toxic. The seeds of the berries contain cyanogenic glycosides as do almonds, apples, cherries and plums that can cause gastro-intestinal problems when ingested raw. They are only edible if crushed and washed.

Gelsemium – family Gelsemiaceae common name Carolina jessamine is a twining vine, native to subtropical and tropical America: Honduras, Guatemala, Belize, Mexico, and south eastern and south-central United States All parts are poisonous, causing nausea and vomiting. It is possible to become ill from ingesting honey made from jessamine nectar.

Gloriosa superba – family Colchicaceae known as the flame lily or climbing lily is highly toxic due to colchicine contained within the plant. The early signs of toxicity develop within two hours of ingestion and include vomiting, diarrhoea, numbness and severe effects on the throat leading to dehydration. It can lead to respiratory, hepatic and renal failure individually and multiorgan failure within 24 to 72 h.

Grevillea Spp – in the family Proteaceae is known by other names including silky oak and spider flower. Grevillea robusta is a fast growing evergreen tree with a single main trunk, growing to 5–40 m (20–100 ft) tall. The bark is dark grey and furrowed and the leaves are fern-like. These are shed prior to flowering. The flowers and fruit contain toxic hydrogen cyanide and tridecylresorcinol responsible for contact dermatitis.

Hedera – family Araliaceae common name Ivy including the rampant colourful Virginia creeper are toxic. All species of Hedera contain irritant and allergenic compounds in all plant parts. They are especially concentrated in young leaves and fruit and remain throughout the seasons. Contact dermatitis can be caused at any time.

Helleborus niger – family Ranunculaceae common name Christmas rose is also toxic. It Contains protoanemonin or ranunculin, which has an acrid taste and can cause burning of the eyes, mouth, and throat, oral ulceration, gastroenteritis, and hematemesis. Hellebore poisoning is rare, but it does occur. These plants are usually left alone by animals such as deer and rabbits because the leaves of the plant produce poisonous alkaloids.

Hippomane mancinella – family Euphorbiaceae known in Spanish as the ‘manzanilla de la muerte ‘apple of death found in the Caribbean region. All parts of this tree, including the fruit, contain Toxic phorbol esters typical of the Euphorbiaceae family.

It contains deoxy, hydroxyphorbol, gamma, alpha-oxide, hippomanins, mancinellin, sapogenin and phloracetophenone. Dimethylether is present in the leaves and physostigmine in the fruit. This tree species according to the Guinness book of records is listed as the world’s most dangerous tree. Hence it is doubtful anyone would want to cultivate it, knowing the consequences that await.

Indian Pea – Lathyrus sativus family Fabaceae. Although not really considered as bonsai material, is often cultivated for its striking blue flowers, but more importantly as an insurance against famine in third world countries where drought is a major problem.

The crop is harmless to humans if ingested in small quantities occasionally, but continuous intake over a prolonged period (3 months) can have serious side effects. The plant produces seeds containing diaminopropionic and neurotixic amino acids and can cause a disorder known as lathyrism. A neurodegenerative disorder causing paralysis of the lower body, emaciation of gluteal muscle and brain damage in children.

Idesia – family Salicaceae. A tree not normally found in western bonsai collections is common in its native regions of China, Japan, Korea and Taiwan. It is a deciduous tree with greyish-green bark and heart shaped dark green leaves 8 to 20cm in length protruding from a red petiole. Flowers are small, fragrant and yellowish green in colour.

The fruit of the Idesia is a small orange berry, which ripens to dark red almost purple in colour, that can be consumed, but as with all wild fruit care should taken in its preparation prior to ingestion. Idesia has no known toxins that are harmful to humans.

Incensed Cedar – Libocedrus decurrens family Cupressaceae. Is a popular species for bonsai as formal, informal and literati styles. It contains strong volatile oils including thujone, a ketone that is known to be toxic in large quantities and it is best known as a chemical compound in the spirit absinthe.

Thujone has a menthol odour and is considered toxic to the brain, kidney, and liver cells and could cause convulsions if used in too high a dose. It should not be used during pregnancy, breastfeeding or those with kidney weakness.

Jacobaea vulgaris – family Asteraceae, commonly known as ‘ragwort’ contains many different alkaloids, including jacobine, jaconine, jacozine, otosenine, retrorsine, seneciphylline, senecionine and senkirkine. This plant is poisonous to livestock including equines and cattle, hence there is concern for people who keep such animals.

Jacobaea vulgaris is also theoretically poisonous to humans, although poisoning is unlikely as it is distasteful and not used as a food source. Nonetheless, some sensitive individuals can develop an allergic skin reaction after handling the plant. Because it contains sesquiterpine lactones, which differ from the pyrrolizidine alkaloids responsible for the toxic effects, that can cause compositae dermatitis.

Juniper – Juniperus sabina also known as the ‘Savin’ Juniper is a popular conifer used in bonsai. In Calgary Alberta Canada it’s popularity is such that it is widely cultivated. However, Savin Juniper is known to be toxic and potentially deadly poisonous if taken in large enough quantities. For example, those who make juniper syrup using Savin Juniper without realizing the potential toxicity.

According to the article by Papavassiliou published in the French journal Société de Médecine Légale in 1937, indicates that in two cases of poisoning, oil of Savin was able to cross the placental barrier. Jacobs and Madari (2004) the oil of Savin (also know as Sabine) was found in the viscera of the foetus demonstrating the ability of the oil to cross the placental barrier.

Savin oil contains sabinene, sabinyl acetate and sabinol, compounds that are structurally related to thujane, thujol, and thujone. The latter are well known for their toxic effects and are found in infamous plants such as Tansy (Tanacetum vulgare) and Wormwood (Artemisia absinthium).

Savin oil can cause irritation of the mucus lining of the intestines, congestion of abdominal organs, congestion of the kidneys leading to haematuria (blood in the urine), menorrhagia (heavy menstrual bleeding) and abortion.

Jacaranda – is a genus of 49 species of flowering plants in the family Bignoniaceae, native to tropical and subtropical regions of the Americas, Africa and cultivated around the world.

The species are shrubs to large trees ranging in size from 20 to 30m (66 to 98 ft) tall. The leaves are bipinnate in most species, pinnate or simple in a few species. The flowers are produced in conspicuous large panicles, each flower with a five-lobed blue to purple-blue corolla; a few species have white flowers.

While Jacaranda flowers are not considered toxic to humans, they can cause mild gastrointestinal upset if ingested. Jacaranda trees are a stunning addition to any landscape or as bonsai, with their beautiful flowers and graceful form.

In these articles on ‘toxicity’ part III we continue the discussion on species ‘K’ onwards, until next time, BW, Nik.

Hi welcome to Taiga Bonzai, we continue out discussion on trees and shrubs often found in bonsai starting with the letter ‘K’.

Introduction – in this section we mention species of tree and shrubs that are found in other regions of the globe. Some have found their way to the west by various means via famous botanists, Carl Linnaeus, (1707 – 1778) Alexander von Humboldt (1769-1859) and George Washington Carver. (1804- 1943) Today many species are available from horticultural establishments and on line purchasing.

Kentucky coffee – Gymnocladus dioicus family Fabaceae. A species native to north America is also used in bonsai. Its rough ash-grey bark similar to that of oak can fall or peel away from its surface leaving scarring and indentations, which adds character to the tree. Its flowers are dioecious and has fruit in the form of a hard-shelled bean in pods from 13cm to 25cm. (5 to 10 inches)

The seeds are considered poisonous as they contain the toxic alkaloid cytosine, that if consumed can cause respiratory difficulties, which can have fatal results. However, it is argued that if the seeds are roasted, the cytosine is neutralized, but for those with respiration problems it is not a risk worth taking.

Kumquat – Fortunella japonica family Rutaceae. The species has no known toxins harmful to humans and is usually grown as an ornamental plant, but is found in bonsai collections. The fruit resembles a small orange a little larger than a grape, its peel has a sweet flavour whilst the inner pulp is sour but is edible when cooked.

It is also ingested in its raw state, but those with a sensitive digestion system should refrain from doing so due to the concentration of oils (Limonene) and acids within the fruit. Which can cause diarrhoea, nausea and other abdominal complaints.

Kurrajong – Brachychiton populneus family Malvaceae, also called the ‘bottle’ tree. Is native to Australia and found in various habitats from wet coastal districts to semi-arid regions. The bell-shaped flowers range in colour from pale cream to pink with simple pointed shaped leaves.

The seeds are covered in small stiff irritating hairs, which have to be removed prior to roasting and ingesting as they contain toxins. Although these are not considered dangerous to humans they can be to domestic pets, sheep and cattle causing lameness, tremors, collapse and in some cases fatality depending on the victims disposition.

Laburnum – family Fabaceae. Is a genus of two species of trees that are Laburnum anagyroides known as the common laburnum and Laburnum alpinum the alpine laburnum. They are often found in bonsai collections due to their colourful yellow pea-like flowers. That are in pendulous leafless racemes 10–40 cm (4–15.5 in) similar to the wisteria, making them very popular trees.

However, all parts of the tree are poisonous; roots, bark, wood, leaves, flower-buds, petals and seeds as they contain the toxin cytosine a nicotinic receptor agonist that produces a biological response. Symptoms may include intense lethargy, vomiting, convulsion, coma and severe diarrhoea.

Laurel (Cherry) Prunus laurocerasus family Rosaceae. Is a shrub often used for topiary in hedging and also in bonsai as it is easily shaped. The leaves are a shiny dark green with creamy white flowers and fruit that turn black when ripe.

The whole plant is poisonous containing the toxin hydrogen cyanide, also known as prussic acid and identifiable by its strong almond-like smell and bitter taste. Symptoms can include breathlessness, weakness, spasms, convulsions, coma and respiratory failure.

Lilac – Syringa vulgaris is a genus of 12 currently recognized species of flowering woody plants in the family Oleaceae native to south eastern Europe and eastern Asia.

This particular species has been historically used in various traditional medicines in Asia for treating ailments including cough, diarrhoea, acute icteric hepatitis, vomiting, abdominal pain, and bronchitis.

Despite the medicinal attributes of the common lilac Syringa vulgaris, the Persian lilac of the Melia genus is very toxic for felines. It can cause gastrointestinal distress, muscle weakness, tremors, and seizures if ingested.

Moreover, lilac is prone to powdery mildew disease. The fungus has no direct negative effects on humans, but it can cause problems for many people who are allergic to this particular mould or suffer breathing problems.

Mistletoe – Viscum album is a hemiparasitic plant in the order Santalales. A mistletoe seed attaches itself to a tree by a structure called the haustorium and is able to germinate independently, but as it develops it penetrates the branch of its host absorbing nutrients and water.

The European mistletoe has evergreen leaves in pairs with waxy white berries in clusters of two to six, that contain the toxins polysaccharides, alkaloids, and lectins. Which can cause blurred vision, nausea, abdominal pain, diarrhoea, blood pressure changes that can be fatal.

Those taking Telmisartan a prescribe drug, which is used to treat high blood pressure (hypertension) should be aware of potential problems. Mistletoe is found in bonsai, but is uncommon as it can affect other species within a collection.

Mock orange – Philadelphus coronarius family Hydrangaceae. A species of flowering plant native to Southern Europe is a deciduous shrub. Growing to approximately 3 m tall by 2.5 m wide and often found in bonsai collections. What makes this a popular collectable species is because of its bowl-shaped double white flowers on prominent stamens, that are highly fragrant.

The ‘toothed’ dark green leaves turn to yellow in autumn adding more colour to the plant. Yet the seeds and flowers carry toxins that although considered mild, are not life threatening. However, they can cause nausea, vomiting, diarrhoea and skin rash if consumed. But much will depend on an individual’s digestive system.

Myrtle – Myrtus communis family Rosopsida. A common species found in bonsai has reddish brown bark that is apt to peel off in mature plants. The flowers usually white in colour have five petals and numerous long stamina and can be heavily scented.

The leaves are small, narrow and dark-green and filled with oil, which is visible as small dots when held against a light. This oil is slightly toxic and may cause headaches, nausea, indigestion, and may colour urine purple if consumed in large quantities.

Nandina – Nandina domestica family Berberidaceae. A common colourful species used in bonsai is not a bamboo plant as it is often referred to. It is an evergreen shrub growing to 2m (7ft) tall by 1.5 m (5ft) in width. In springtime new leaves are a bright pink, which turn a glossy green. The flowers are white and in clusters, with fruit in the form of a bright red berry.

All parts of this tree are poisonous as it contains compounds that produce hydrogen cyanide, which could be potentially fatal if ingested. Although there are those who claim the tree is non-toxic to humans, ascertaining if there is any truth to the argument is not worth the risk.

Neea – Neea buxifolia family Nyctaginaceae in the Saltwood genus. Often referred to as the flowering tropical boxwood is native to Puerto Rico. It is a rather twiggy specimen with a large diameter trunk with small long narrow oblong leaves, with new shoots appearing in dark red, flowers and red fruit.

No part of this tree should be ingested as it belongs to the Nyctaginaceae family, in which many members such as the Bougainvillaea another favourite in bonsai are poisonous. Symptoms are similar to that of poison ivy and may include, pain, itching or burning skin, blisters and dermatitis.

Nutmeg – Myristica fragrans. Although uncommon in western bonsai collections, can be found in more temperate climes. The problem with Nutmeg seed propagation is that there is no way of knowing once germination has taken place, if the plant is male or female. Because this species is dioecious and male trees are unproductive.

The common way if one desires a female fruiting tree is to take a cutting from a female plant, then either graft, patch bud or air layer, or via the ‘T’ graft method. This is carried out in late winter or early spring, using dormant scion wood.

The Nutmeg although widely use for culinary uses contains the toxin myristicin, a monoamine oxidase inhibitor and psychoactive substance. If ingested in large quantities can induce convulsions, palpitations, nausea, dehydration and generalized body pain.

In the next article of this series ‘toxicity’ we will continue with the letter ‘O’ going forward, until next time, BW, Nik.

Hi welcome to Taiga Bonzai, we continue our discussion albeit alphabetically through the list of shrubs and trees that have defence attributes.

Introduction – some of these defensive toxins are harmful to domestic pets and also to humans. Consuming any part the of tree/shrub can cause severe ailments for example, Rhubarb in the family Polygonaceae.

The use of rhubarb stalks as food is a relatively recent innovation first recorded in 18th to 19th-century. However, the leaves of the plant are poisonous as they contain such substances including, oxalic acid, a nephrotoxin. Yet the stalks are widely used for making pies, tarts, crumbles and in wine production.

Oak – Quercus. family Fagaceae. A deciduous and evergreen tree with a variety of species that include, white oak Quercus alba and stone oak Lithocarpus. Oak leaves and acorns are poisonous as they contain tannic acid, which can cause kidney damage, gastroenteritis and diarrhoea in livestock for example.

Sheep, goats, horses and cattle, but it has little effect on the domestic pig. It is said humans are not affected providing the tannins have been removed nonetheless, those with sensitive digestion systems should avoid consumption.

Oleander – family Apocynaceae. A small tree or shrub having approximately 400 different varieties in the genus Nerium, can be found in many temperate zones throughout the world. It is widely cultivated as an ornamental plant for parks and gardens reaching heights of 2 to 6.5m. (19ft) Although there now exist many dwarf varieties, which only grow to 26cm (10 ins) and these can be found in some bonsai collections.

Oleander when mature has grey bark, with dark green thick leaves arranged in pairs that are relatively narrow in shape. The flowers from white to pink to red are highly scented although much depends on the variety and fruit in a long pod.

These when ripe open to reveal large amounts of seed. Oleander although a very attractive plant, is considered extremely poisonous as it contains the toxins oleandrin and oleanrigenin that are referred to as cardiac glycosides.

Ingesting any part of an Oleander can cause serious gastrointestinal problems; nausea, vomiting, excess salivation, abdominal pain and diarrhoea. Other reactions to Oleander glycosides include cardiac and central nervous system effects. An irregular or erratic heart rate and drowsiness, muscle tremors, seizures and collapse that can have fatal consequences.

Olive – Olea europaea. family Oleaceae. Olive trees are not toxic and ingesting the fruit has no known side effects. However, olive tree pollen is extremely allergenic and according to the Ogren Plant Allergy Scale. A rating system for plants measuring their potential to cause allergic reactions in humans, it has a rating of 10 out of 10. As the olive tree is wind-pollinated and the pollen if inhaled, can cause headache, blocked sinuses, breathing difficulties and serious asthma attacks.

Orange jasmine – Murraya paniculata. family Rutaceae. A tropical evergreen tree or shrub from Asia is a common specimen for bonsai. It has glossy leaves and white scented fragrant flowers that can remain throughout the growing season and fruit ranging from orange to red, resembling the kumquat.

The orange jasmine has no known toxins harmful to humans, but the flowers are highly allergenic and can cause headache, blocked sinuses and breathing difficulties and in some instances severe asthma.

Plum – Prunus Spp. family Rosaceae. Is a diverse group having many species between 19 and 40 according to taxonomists. Arguably the most common plum trees used in bonsai are the European plum Prunus domestica and the Japanese plum Prunus salicina. The flowers are fragrant and vary from white to cream, to various shades of pink.

The fruits are usually globose to oval between 2cm to 6cm in size with firm flesh surrounding a hard seed pod. Plum seeds contain the toxin cyanogenic glycosides including amygdalin that decompose into a sugar molecule. Resulting in the production of Hydrogen cyanide gas, which is extremely poisonous and flammable.

Podocarpus – Podocarpus neriifolius. family Podocarpaceae. There are approximately 97 to 107 species in the genus that are related to conifers and can be found in bonsai collections. Podocarpus are evergreen with cones forming a brightly coloured fleshy, berry-like receptacles inviting birds to feed and in so doing the seeds are dispersed through their digestive tracts.

Podocarpus are also related to yews, thus their leaves, stems, bark and pollen are cytoxic. In spring and early summer, the male Podocarpus blooms and releases the cytotoxic pollen. Exposure to this can create an effect mimicking the cytotoxic side effects of chemotherapy, where blood cells or bone marrow are most at risk of developing serious infections.

Privet­ – Ligustrum vulgare, family Oleaceae. A species native to Europe, Australia, Africa and Asia is commonly used in bonsai. Species include the Japanese privet Ligustrum japonicum, Chinese privet Ligustrum quihoui, which are mainly used for ornamental plants and Ligustrum ovalfolium for hedging purposes.

The latter if managed regularly is quite decorative, but if left to its own devices will become unruly. Privet leaves and bark have bitter properties, which in China are used for making herbal teas. However, privet species that yield fruit should not be ingested as they are toxic. Symptoms include nausea, headache, abdominal pains, vomiting, diarrhoea, low blood pressure and weakness.

Quince – Cydonia oblonga family Rosaceae. Include such species as Chaenomeles japonica and Pseudocydonia sinensis that are small deciduous fruit and flowering trees. The flowers borne in clusters vary according to the species from pale pink to red and both species bear fruit in the form of a pome.

This pome is bright golden-yellow at maturity and although the fruit is edible, it is astringent and can cause a shrinking or constriction of the body tissues for example. A dry puckering of the mouth due to the tannins present. The quince has been used for both culinary and medicinal purposes. But it is poisonous as the seeds contain nitriles, that if ingested will be hydrolysed by the stomach acid producing hydrogen cyanide.

It is strange to think that many plants used for both medical and culinary purpose are quite toxic. Yet if they are prepared correctly they are made safe to consume. In the next article on this subject we continue the discussion beginning with the letter ‘R’ onwards, until next time, BW, Nik.

Hi welcome to Taiga Bonzai, we continue our journey through the alphabet starting with the letter ‘R’.

Introduction – all trees and shrubs have some form of defence, some highly toxic and dangerous to domestic animals and humans. Whilst others are not considered harmful. Yet some whom work with these plants do not take adequate precautions, hence with negative results.

Rhododendron – Spp. family Ericaceae. Contains approximately 1,024 species of trees and shrubs. Both evergreen and deciduous and found throughout the world, from north America, Europe and Asia. They are a common addition to any bonsai collection, due to their colourful showy flowers that bloom from late spring to early summer.

All Rhododendron species including, Rhododendron obtusum, Rhododendron simsii, Rhododendron indicum and Rhododendron luteum are poisonous. They contain Andromedotoxins that are water-soluble diterpenoid compounds in the leaves flowers and nectar.

If any part of the plant is ingested symptoms include, salivation, a burning sensation in the mouth, emesis, diarrhoea, muscular weakness, impaired vision and dyspnea. Hypotension and atrioventricular block, a serious cardiovascular effect that may have fatal results.

Rosary Pea – Abrus precatorius. family Fabaceae. Known by other names including the ‘Jequirity bean’ is native to warm and tropical regions and also found in bonsai. Those with children and domestic pets are advised not to keep such a plant due to its very nature.

This species with its frond-like leaf formation and bright red fruit is extremely poisonous as it contains the toxin abrin. This is similar in structure to ricin the toxin in Ricinus communis or ‘Castor bean’ plant and some claim that abrin has a higher toxicity level. Abrin is found in all parts of the plant but, it is the seeds that attract the most attention and if crushed, chewed and ingested abrin is released and can be fatal.

Rowan – Sorbus aucuparia. family Rosaceae. Native to the northern hemisphere are also found in more temperate climes including Africa and Asia. Its growth can be prolific portraying grey bark, compound frond-like leaves and scented flowers white to cream with orange to red berries.

This combination makes the species very attractive to bonsai collectors. Nonetheless, rowan tree berries are poisonous as they contain parasorbic acid, which is used as a food preservative and in cosmetics. Symptoms can include, eye and respiratory problems, skin irritation and abdominal pain. However, if they are cooked the parasorbic acid is transformed into sorbic acid, which is not poisonous if ingested.

Snowberry – Symphoricarpos alba family Caprifoliaceae. Also know as the ‘ghost berry’ and ‘wax berry’, a genus of approximately 15 species native to north America are found in other parts of the world.

They are members of the honeysuckle family Caprifoliaceae used in bonsai for their fragrance and decorative flowers and coloured fruit, white, pink and red depending on the species.

The white berries of Symphoricarpos contain the following toxins, viburnin, chelidonine, saponins, tannins, terpenes, tryglycerides and coumarins. If ingested the symptoms are vomiting, blood in urine and delirium. However, the toxic combination has a powerful emetic effect – a gastrointestinal irritant, which causes the victim to expel the berries undigested.

Spindle tree – Euonymus europaeus. family Celastraceae. A native to Europe is a deciduous tree or shrub noted for its colour changes during the season. It has leaves that change from dark green to yellow to red to purple and flowers yellow to green grown in clusters.

The fruit, which can be pink, red or purple when ripe open to reveal its orange coloured seeds. This colour change make it a popular specimen for bonsai. However, the fruits are poisonous, a cocktail of toxins including, alkaloids theobromine, caffeine and terpene. Poisoning in children is quite common as the brightly coloured fruits are attractive. Ingesting the fruit can cause liver and kidney damage and can be fatal.

Spurges – Euphorbia Spp. family Euphorbiaceae. A genus with over 500 species of trees and shrubs including Euphorbia tirucalli, a tall growing shrub native to semi-arid tropical climates. It has a wide distribution throughout Africa and is common in the dry states of north America in particular California.

In bonsai E.tirucalli is not one of the most favoured of specimens although it can be found, because of the problems of shaping and pruning. For example, merely cutting a branch or twig causes the plant to ooze a sticky white toxic latex.

This latex when in contact with skin is extremely irritating causing redness and a burning sensation. If in contact with the eyes the result is severe pain and temporary blindness. If ingested symptoms are burning to the mouth, lips and tongue and can be fatal.

 Tamarac – Larix laricina. family Pinaceae. Known as the black, eastern, red and American larch, is native to north America and Canada. This species is both coniferous and deciduous due to its needle leaf structure that is shed in the autumn.

The Tamarac has more medicinal qualities as opposed to toxicity for example. Tea made from the bark was used as a laxative, a remedy for rheumatism and skin ailments.

However, this species is prone to attack from the fungal pathogens including Lachnellula willkommii and contact with it should be avoided. It is also argued that oil from the leaves in contact with the skin can cause dermatitis nonetheless, it is a popular species found in many a collection.

Titoki – Alectryon excelsus. family Sapindaceae. Formerly known as the New Zealand oak is as its name suggests native to this antipodean realm. Like its European counterparts it has a twisted trunk with branches radiating in all directions and its apex is formed into a canopy.

Its flowers are relatively small and purple in colour and it’s fruit are a pink to grey capsule that when ripe, open up to reveal a bright red pulp with a black seed. The Titoki seen in some bonsai collections is poisonous, it contains tannins and cyanide producing poisons in the bark, leaves and fruit. If ingested can cause; vomiting, gastroenteritis, diarrhoea, delirium, kidney failure and at worse fatality.

Tea tree (Chinese) – Camellia sinensis family Theaceae. This is an evergreen shrub that if left to its own devices can grow in access of 5 metres (16ft) in height. Producing white flowers with bright yellow stamens surrounded by glossy green leaves and fruit having a hard green shell and a single brown seed contained within.

There are many cultivars of the tea tree that are used to make a refreshing beverage partaken by countless individuals including, the Camellia sinensis assamica (Assam, India) strain. Nonetheless, the tea tree is considered poisonous because it contains caffeine and tannin toxins that are addictive.

It is argued that consuming five cups a day are sufficient to produce addiction and reduced intake or withdrawal. Causing; dizziness, headaches, palpitations, indigestion, constipation and insomnia. Moreover, excessive intake or over indulgence can be harmful to pregnant women.

In the next article on this subject ‘toxicity’ we continue with the letter ‘U’, until next time, BW, Nik.

Hi welcome to Taiga Bonzai, we continue our journey through the alphabet discussing the toxicity of trees and shrubs, some of which are used in bonsai horticulture.

Introduction – some of the species mentioned here are endemic to tropical and sub-tropical regions, others are found in the northern hemisphere.

Umbrella tree – Schefflera arboricola. (syn. Heptapleurum arboricolum) also a member of the Araliaceae family is native to Taiwan, but can be found world-wide as a house plant and also in bonsai. S. arboricola should not be mistaken for S. actinophylla, because of the height difference.

Moreover, S. arboricola has different leaf colour and patterns, some variegated with cream to white flowers with yellow edges or centres. Although much depends on the individual cultivar. S. arboricola is poisonous and carries the same toxins as S. actinophylla. Leaf consumption can cause mouth tingling and numbness, vomiting and abdominal pain and sap when in contact with skin can cause irritation and rash.

Viburnum – Lantana. family Adoxaceae. Also known as the ‘wayfaring tree’ is a deciduous shrub native to Europe, but can be found in Asia and northern Africa and is a relatively common specimen in bonsai.

It’s oval dark green leaves have a downy or hair like covering on the underside and flowers that are creamy white in colour and green fruit. These ripen to a bright red eventually turning black when mature. The berries if consumed although mildly toxic can cause vomiting, diarrhoea and abdominal pain if ingested in large quantities.

Viburnum – Opulus. family Adoxaceae. Is often referred to by its common name the ‘Guelder rose’ and is native to Europe, northern Africa and central Asia. This deciduous shrub has three lobed leaves that are opposite to each other having an appearance similar to maples.

The flowers in clusters are white in colour with their centre being fertile surrounded by an infertile ring that are produced in early summer; the fruit that is bright red. The berries if consumed although mildly toxic can cause vomiting, diarrhoea and abdominal pain if ingested in large quantities.

Virginia creeper – Parthenocissus quinquefolia. family Vitaceae. Is native to north America, Canada, Mexico, Guatemala and Europe. It is a prolific deciduous climbing vine reaching heights of over 30m. (100ft) It attaches itself to smooth surfaces by small adhesive pads.

This plant normally seen growing on the sides of buildings has striking colours throughout the seasons. The leaves change from various greens to yellow to orange to red and purple and this colour change makes the species attractive to bonsai.

The flowers are small and greenish white in colour, which change into purple/black berries in the autumn. The sap, leaves and berries are poisonous because they contain the toxin oxalic acid. Prolonged skin contact can be dangerous and ingesting any part even small amounts can cause kidney damage and death to humans.

White cedar – Spp. family Cupressaceae. Include Chamaecyparis thyoides – Atlantic white cypress, Cupressus lusitanica – Mexican white cedar, Thuja occidentalis – Northern white cedar, Thuja plicata – western red cedar and Cryptomeria japonica – Japanese cedar. Cedars are conifers and are found in many parts of the world, from northern climes to temperate zones.

They have many uses for example, grown as barriers, wind breaks, dense hedging in parks and gardens and are a common species in bonsai. However, all cedars carry toxins the primary irritant being plicatic acid and some are more potent than others for example.

The western red cedar and Japanese cedar have the highest content of plicatic acid and exposure to it can cause severe asthma, rhinitis or conjunctivitis, that can be progressive. In addition, plicatic acid in contact with skin can cause a hypersensitivity reaction, a type of response seen in tuberculin skin tests.

Willow – Salix alba. family Salicaceae. Is a species native to Europe, but is also found in western and central Asia. Within this genus are: Salix alba Vitellina – a willow with yellow shoots and Salix alba var. Britzensis, Cardinal and Chermesina having orange to red shoots.

The willow a medium sized deciduous tree can be in a weeping form or with a dome shaped crown with long thin leaves pointed at the end. (5–10cm long x 0.5–1.5cm wide) It is often found in bonsai in designs that include slanting (Shakan) and (Fukinagashi) wind swept.

Male and female trees each produce their own flowers in the form of catkins that appear in the spring and when mature are wind pollinated. However, the willow contains salicylate toxins in the bark that if ingested can cause the following. Ulcers, nausea, vomiting, stomach bleeding, kidney inflammation, tinnitus and skin rash.

Wisteria – Spp. family Fabaceae. Includes various species of climbing vines. (Plants that climb by their shoots) Wisteria brachybotrys, Wisteria brevidentata, Wisteria floribunda, Wisteria frutescens, Wisteria macrostachya, Wisteria sinesis, Wisteria venusta and Wisteria villosa.

These Wisteria types are predominantly native to the eastern north America, China, Japan and Korea. Although these species are found in bonsai, arguably the most common is the Wisteria sinesis that when in bloom has a striking floral display for example.

The great wisteria at the Ashikaga flower park in Tochigi, Japan, which covers more than 1,990 square meters over half an acre. Wisteria flowers are between 10 to 80cm in length and produced in pendulous racemes and are either purple, violet, pink or white.

All parts of the wisteria are poisonous, they contain the toxin saponin and if ingested the symptoms are: nausea, vomiting, abdominal pain, diarrhoea, severe gastroenteritis, dizziness, confusion, speech problems and collapse.

In the next article on ‘Toxicity’ we conclude our journey through the alphabet with ‘X’, ‘Y’ and ‘Z’. Until next time, BW, Nik.

Hi welcome to Taiga Bonzai, we continue our journey through the alphabet discussing the toxicity of trees and shrubs, some of which are used in bonsai horticulture.

Introduction – some of the species mentioned here are endemic to tropical and sub-tropical regions. Yet they can be found quite easily at garden centres and nurseries.

Xanthorhiza – Simplicissima. family Ranunculaceae. The only member of the genus Xanthorhiza, is native to the eastern states of north America. In the wild this shrub grows in sandy soil to a height of approximately 90cm. Its leaves are in a spiral configuration up to 18cm in length with flowers (6 to 20cm) that are produced in star shaped forms of reddish brown to purple.

This attractive plant although used for ground cover in gardens, is uncommon in bonsai as its main stem does not produce a large girth. Xanthorhiza is poisonous, its contain the toxin berberine, which can cause nausea, dyspnoea, diarrhoea, nephritis, urinary tract disorders, skin and eye irritation.

Xanthoceras – Sorbifolium. family Sapindaceae. Native to northern China is a flowering and fruiting species of small tree growing to approximately 8m and can be seen in bonsai collections although uncommon.

Its mid-green leaves 12–30cm in length are pinnate with flowers 10–20cm long containing 5 white petals arranged in panicle form, that appear in spring. The fruit a leathery pod splits open in three sections when ripe to reveal the black seeds, which resemble a small horse chestnut seed.

Originally the flowers, leaves and fruits were eaten raw with little or no side effects evident. Nonetheless, it would be prudent for those with sensitive digestive systems to cook them before consumption.

Yew – Taxus Spp. family Taxaceae. Yews are widely used in landscaping, ornamental horticulture and bonsai in which over 400 cultivars have been created including. The Japanese yew Taxus cuspidata, Pacific yew Taxus brevifolia and Canadian yew Taxus canadensis.

All these various species have derived from the European yew Taxus baccata considered as Europe’s oldest living tree of which, a specimen can be found in St Cynog’s church yard in Wales, dated to approximately 5000 years. The yew majestic and sombre in its appearance has a reputation as a harbinger of bad tidings for example.

The yew tree often found in church graveyards as a symbol of sadness was also made into longbows, a weapon used in the battle of Agincourt 1415 by the English in their defeat of the French cavalry.

Yews are relatively slow-growing and can reach heights of 20m (66ft), with a trunk girth averaging 5m. (16ft) The bark is reddish brown with lanceolate, flat dark-green leaves positioned in a frond-like form on the stem. The fruit consists of a bright red cone called an Aril in which a single seed is contained, these are subsequently consumed by birds who disperse them via their digestive system.

All parts of the yew with the exception of the Aril are highly poisonous to humans as they contain the toxin taxane, that can cause the following if ingested. Low blood counts, arthralgias and myalgias, pain in the joints and muscles, peripheral neuropathy – numbness and tingling of the hands and feet.

In addition, hair loss, mouth sores, nausea, vomiting, diarrhoea and in some cases the results can be fatal. Moreover, male and monoecious yews in this genus release extremely small cytotoxic pollen, causing headaches, lethargy, aching joints, itching, and skin rashes and asthma.

Zanthoxylum – Kauaense. family Rutaceae. Is a genus containing approximately 250 species of coniferous and deciduous trees and shrubs, indigenous to temperate and sub-tropical regions. It is known as the ‘prickly ash’ and is a common species in bonsai.

The bark has limpet shaped protrusions containing sharp thorns at the centre. Its bright green leaves are oval to oblong in shape with 6 to 8 in pairs on a single stem. The fruit are dull red berries tightly arranged in a cluster, that when ripe are used to make the spice Sichuan pepper.

According to Asian herbal remedies, the bark was extensively used as a remedy for rheumatism, toothache and colic. Zanthoxylum is not considered poisonous to humans, but it does have the toxin Sesamin.

This toxin can cause digestive issues including, nausea, diarrhoea and abdominal pain. Other symptoms may include Anaphylaxis, an extreme case of allergy caused by Sesamin. All edible parts of the tree must be properly prepared prior to ingestion.

Zelkova – Serrata Spp. family Ulmaceae. Often know as the Japanese or Chinese elm has two varieties, Japan and mainland eastern Asia Zelkova serrata var. serrata, and in Taiwan Zelkova serrata var. Tarokoensis. Z. serrata is a deciduous tree that in the wild can reach a height in excess of 30m (100ft +) and is favoured for its ornamental characteristics.

Z. serrata has a short fat trunk from which many branches radiate in a typical broom style. (Hokidachi) Its leaves are round to oblong in different shades of green, (Depending on the species) that change through the seasons to yellows, oranges and reds.

The flowers in clusters are yellowish-green, which turn brown as they mature. Z. serrata a popular species is regularly found in bonsai collections. Z. serrata has in the past been used for herbal remedies including stabilising the womb during child birth nonetheless, it would be prudent to seek advice before ingesting parts of this species.

The trees and shrubs mentioned in the compiled list are all toxic to some degree for example. In the beginning of this discussion information was given on the Acacia, a native of the African savanna, that have an abundance of thorns for protection. They also use poison in their leaves as a second line of defence against predation, predominantly from browsing wildlife.

Flora once indigenous to specific climate zones are now common place throughout the world in parks, gardens and bonsai, due to their discovery and availability. These species cultivated for their fruit and flowers and other uses, all have some form of defence.

Their toxicity ranges from mild, meaning having little effect on humans and domestic pets, to being potentially fatal as in the Manchineel tree Hippomane mancinella. Commonly known in Spanish as ‘manzanilla de la muerte‘ in English ‘the little apple of death‘. Which the conquistadors found to their cost when they invaded the Caribbean from 1519 to 1521.

Even the most toxic of bonsai specimens, the European Yew – Taxus baccata can be handled, providing we refrain from ingesting any part of it and ensuring that any body part in contact, predominantly the hands and the tools we use are thoroughly cleaned.

As to a particular species’ poisonous capabilities we are basically unconcerned, probably due to its benign appearance or attractiveness and addition to a bonsai collection. Nonetheless, this article was written in order to shed some light on floral toxicity and the potential hazards that exist.

These articles on ‘toxicity’ ‘A to Z’ concludes our journey through the alphabet discussing the defence mechanisms of trees and shrubs. But, like all flora they are vulnerable, prone to attack from pests and disease; a topic to turn to in the next article. Until next time, BW, Nik.

Hi, welcome to Taiga Bonzai, we have written articles on a selection of pests and disease recently. As a result our followers (horticulturists and bonsai enthusiasts) have asked for further research on this subject.

Introduction – in the last article we concluded our discussion on the ‘Toxicity’ of various shrubs and trees and their potential to be mildly irritant to being potentially fatal. However, all flora regardless of their ability to defend themselves are prone to attack from pests and disease. This increasing problem creating havoc on the world’s horticulture production and effect on society, is not a new phenomenon; it is the result of mankind’s actions.

Since the dawn of time – mankind’s actions have caused catastrophic consequences in many ways, the world is facing unprecedented challenges that will be extremely difficult to resolve. Have we reached the point of no return? Some believe that we have past it, others are more complacent, ‘These situations need to be addressed but they can be resolved’.

During our travels around the globe we have been privy to some extraordinary and amazing locations, returning to them at a later date we note that many have been destroyed. Piles of rubble, barren land, some are now heavily polluted – rife with pestilence and disease. Such experiences do not wane, they remain strong and clear in the mind. How have we arrived at this juncture? Follow our journey as we try to shed some light on the issue.

The beginning – according to scientific research vegetation had evolved on Earth approximately 700 million years ago with fungi and bacteria approximately 1,300 million years prior. This evidence is based on the earliest fossils of those organisms. The general consensus is that organisms also called microbes are beneficial for example, they keep nature clean by helping break down dead plants and animals into organic matter.

Mankind’s contribution – the hunter-gatherer culture developed among the early hominins of Africa, with evidence of their activities dating as far back as 2 million years. According to Richard B. Lee & Richard Daly (Cambridge Encyclopedia: Hunters and Gatherers) “Was humanity’s first and most successful adaptation, occupying at least 90 percent of human history“.

In addition, it is understood that through archaeology, anthropology, genetics, linguistics and the advent of writing from primary and secondary sources, this information is relatively common knowledge.

Colin Tudge in his book ‘Neanderthals, Bandits and Farmers: How Agriculture Really Began’. New Haven, CT: Yale University Press (1998) contends that “The Neolithic saw the Agricultural Revolution begin between 10,000 and 5000 BC in the Near East Fertile Crescent” (Mesopotamia). During this period humans began the systematic husbandry of plants and animals and agriculture advanced.

Many humans transitioned from nomadic to a settled life style as farmers in permanent settlements. The relative security and increased productivity provided by farming allowed communities to expand into increasingly larger units, fostered by advances in transportation.

However, Alina Polianskaya of ‘ Inews.co.uk‘ (March 15th 2018) points out that “Early humans may have been trading with each other much earlier than previously thought. Scientists excavated ancient artefacts at Middle Stone Age sites dating back 300,000 years at the Olorgesailie Basin, in southern Kenya. They uncovered weapons made of materials that could not be found there, suggesting hominins at the time may have exchanged goods with others.”

In his paper ‘Evolution: What Makes a Modern Human’ Nature. 485 (7396) (2012) Chris Stringer tells us that “Modern humans spread rapidly from Africa into the frost-free zones of Europe and Asia around 60,000 years ago.” This notion is supported by Adam Hart-Davis in his work ‘History: The Definitive Visual Guide’. New York: DK Publishing.

He contends that “The rapid expansion of humankind to North America and Oceania took place at the climax of the most recent ice age. At the time, temperate regions of today were extremely inhospitable. Yet, by the end of the Ice Age, some 12,000 years ago, humans had colonised nearly all ice-free parts of the globe“.

The Silk Road – a network of trade routes connecting China and Far East with the Middle East and Europe, was established when the Han Dynasty in China officially opened trade with the West in 130 BC. Although these Silk Road routes were protected from exterior forces by the Han and other countries under signed treaties, pests and disease also travelled with the traders.

This lead to infection, sickness and often death, because those who came into contact with these infectious bacteria had no immunity for example. October 12, 1492, the day when Christopher Columbus landed on the island of Guanahaní (San Salvador now part of the Bahamas.) The beginning of what was yet to come.

The Silk Road routes remained in use until 1453 AD, when the Ottoman Empire boycotted trade with China and closed them. It has been nearly 600 years since the Silk Road was used for international trade, but the routes have had a lasting impact on commerce, culture and history that resonates today and are being reopened.

International trade is arguably the most important factor in the modern world, as nations rely on others to supply the many types of commerce they need. Agreements are signed to lessen the bureaucracy nonetheless, international trade does bring problems as we shall find out in this series.

Yet some countries enforce stringent rules on imports for example, Australia probably has the strictest regulations on what is imported. Meat products, fruit and plant material including seeds from many countries including Asia and Middle East are prohibited.

However, some are permitted if the exporter is registered and has the required documentation. Unlike the rest of the world Australia (although having its own disease problems) is free of many other known diseases and has been since 1872, due to stringent pre and post-border measures. Meanwhile the rest of the world continues to battle with disease containment.

Today much has changed, we have advanced – science and technical horticultural knowledge has allowed us to become adept in food production. New plant species have been introduced, more variety and apparently more taste – but have we gone too far?

The reason why this question is asked is because for every action there is a reaction often resulting in irreversible consequences. Now pests and disease endemic to a particular part of the world are now commonplace in many other regions where flora has no defence.

How this phenomenon occurred is partly due to the fact that pests and disease are able to migrate via wind and wing over vast areas for example. The locust derived from the Latin locusta, in the family Acrididae a swarming insect that devastates vast areas of crop land is able to fly up to 2000 metres covering 200km per day.

Between June 2019 and February 2022, a major outbreak of desert locusts began developing, threatening food supplies in East Africa, the Arabian Peninsula and the Indian subcontinent. The outbreak was the worst to hit Kenya in 70 years, and the worst in 25 years for Ethiopia, Somalia, and India.

However, pests and disease are transmitted by other means including packaging, cross contamination, from animals, by dust suspended in the air and by food and water. But in the main it is the consequence of our actions, for which mankind is ultimately responsible. In the next article of ‘Unseen invasion’ we look at some examples of this, until next time, BW, Nik.

Hi, and welcome to Taiga Bonzai, in this article we continue trying to make sense of mankind’s actions both past and present and the consequences that have happened. Those that will inevitably occur at some future juncture is not a question of if, it is a question of when.

Introduction – the Microbe as we have stated can exist in a single-cell form or a colony like bacteria and fungi and although they are often associated with dirt and disease, most are beneficial. But as we are aware there exist those microbes, fungi and pathogens that have lethal potential. The result is human infectious diseases, mayhem and death. Evidence shows that mankind has shaped the world in his own volition, but the outcome is questionable.

The stowaways – on December 7th 1941 at 7:55 a.m. (Hawaii time) the Imperial Japanese Navy, under the command of Admiral Isoroku Yamamoto attacked the American naval base at Pearl harbour.

According to Gill, G. Hermon (Royal Australian Navy 1939–1942. ‘Australia in the War of 1939–1945’. Series 2) “Over the course of seven hours there were coordinated attacks on the U.S. held Philippines, Guam and Wake islands and on the British territories in Malaya, Singapore and Hong Kong.” This prompted the Americans and British to step up military armament production as further confrontation on the territories of Australia and New Zealand was deemed imminent.

As armament production increased, it was packed in wooden crates and transported to the docks where it stayed prior to being loaded on to transport ships. During this inactive period many insect species entered the crates possibly to find shelter and or hibernate.

Once the crates reached their destinations and were unloaded the insects (those that had survived the journey) were free to wander. In 1945, the first wasp Vespula germanica endemic to the Northern Hemisphere was discovered at an air force base near Hamilton in New Zealand, it has been suggested that a hibernating queen had arrived in a crate containing aircraft parts from Europe.

V. germanica was also found in Tasmania in 1959 and by 1978 had crossed the Tasman Sea and entered Australia. Now countless colonies are common place in Victoria, South Australia, New South Wales and Western Australia. V. germanica nest in cavities that include holes in the ground, spaces under homes, wall crevices, eaves and rafters.

This predator having no known enemies attacks bee hives, killing bees at will -a major problem for the Australian and New Zealand honey industry. V. germanica needs no provocation and will attack all including humans with devastating results.

According to Elle Hunt in her article for ‘The Guardian’ (Jan 17th 2017) analysis shows that “Australia’s bees and wasps revealed to be as dangerous as its snakes, more than half of deaths from bites and stings between 2000 and 2013 were the result of anaphylactic shock.”

Was the introduction of V. germanica to Australia and New Zealand a simple mistake or a blatant error of judgement? Whatever the arguments the consequences are dire, these two countries have a major problem on their hands. Similarly much can be said of other nations whom transport their merchandise around the globe with the same complacent attitude.

The wasp solution – scientists have devised a plan to eradicate wasp colonies by introducing a parasite into the nests that will destroy all within, including eggs, larvae and adults. In the short term the plan might work, but in the long term it is doubtful given the vast areas that V. germanica has colonised in Australia. Moreover, how do you control the parasites? As we have stated for every action there is a reaction.

Another example of stowaway invasion is the ‘Brazilian Wandering’ spider also known as the (Banana spider) Phoneutria a genus of arachnids in the family Ctenidae. They are mainly found in northern South America, with one species in Central America. P. nigriventer a member of Ctenidae is a large arachnid and has a leg span of 13 to 18 cm (5 to 7 in). Their body length ranges from 17 to 48 mm. (⁴³⁄₆₄ to 1+⁵⁷⁄₆₄ in) 

The genus Phoneutria include a few species of spiders known to present a threat to humans. In densely populated areas, Phoneutria usually search for cover and dark places to hide during daytime. Leading them to hide in houses, clothes, cars, boots, boxes, log piles and in banana plantations their preferred hunting ground.

These arachnids will bite if accidentally disturbed injecting venom with serous consequences. There are many reports of humans being bitten when in contact with these creatures. For further reading on this arachnid visit the link below.

https://en.wikipedia.org/wiki/Phoneutria

A few years ago we were making a film on aquatic creatures for the Vaasa Natural History museum in West Finland. Visiting the entomology section we noticed that on display was the ‘Brazilian Wandering’ spider P. nigriventer. We asked the curator where did it come from, because they are not found in Scandinavia. The reply was that the arachnid was discovered in a box of bananas at the local supermarket. Fortunately for the member of staff who discovered it, the spider had not survived it’s journey.

As we stated previously due to the lapse in concentration and due diligence, creatures including pests and disease are everywhere. In the next article on ‘Unseen invasion’ we look at the devastation pests and disease are able to create, starting with the borers. Until next time, BW, Nik.

Hi welcome to Taiga Bonzai, we continue our discussion on pests and disease with a selection of beetles whom bore their way into the trunk of trees. The damage caused by these insects is often results in the tree’s demise.

Introduction – borers are perhaps the most harmful to trees, they once were endemic to certain parts of the globe, but are now found in other parts of the world. Eradication of these insects is an on going battle with no conclusive results.

Airborne invasion – we know that many pests and disease have migrated throughout the world by conventional methods, in the packaging containing merchandise and sometimes in the merchandise itself; mainly via land sea and air.

However, these modes of transportation are not the only way for pests and disease to migrate to other realms. There are those whom are able to take to the wing and reach altitudes of 2,000m some actually fly, whilst other drift on the air currents.

Dutch elm disease (DED) – first appeared in the north-west of Europe about 1910 and between 1914 and 1919, several Dutch scientists carried out influential research on the cause of the disease. According to Forest research.gov.uk this disease “Is one of the most serious tree diseases in the world.” The fungus that causes the disease is spread by bark beetles triggering foliage and tip dieback in all of Britain’s native elms: Ulmus procera, U. carpinifolia and U. glabra. https://www.forestresearch.gov.uk

The disease first spread to Britain in the 1920s, where it killed 10-40% of elm trees. Although the initial epidemic died down, a more aggressive species of Dutch elm disease fungus was accidentally introduced into Britain in the 1960s.

This second epidemic took hold of lowland central and southern Britain where there were English elms in the early to mid-1970s and by 1980, most mature English elms had died. Scattered pockets of mature elm occasionally survived where the geographic situation has facilitated an effective and continuing sanitation control programme.

By the late 1980s the bark beetles used up most of the mature elms that they relied on for breeding material, so beetle populations declined and the disease virtually disappeared from many southern and south-western areas.

In 1982, Forestry Commission research on the biology of Ophiostoma novo-ulmi, an extremely virulent species from Japan has devastated elms in Europe, North America, Asia and now is spreading across across Eastern Europe. (Romania to Poland)

This suggested that the disease would not decline in intensity or contrast to the first epidemic, caused by O. ulmi. The new pathogen, O. novo-ulmi, would return in a continuing cycle to attack the following generation of small elms once they were large enough to support beetle breeding.

Cryphonectria parasitica  – a pathogenic fungus a member of the Ascomycota (sac fungi) native to East Asia and south-east Asia was introduced into Europe and North America in the early 1900s spreading rapidly causing significant tree loss in both regions.

This disease came to be known as ‘chestnut blight’ due its infestation of Chestnut trees Castanea dentata, it has had a devastating economic and social impact on communities in the eastern United States. Once a tree begins to decline it is often dead within a few years and eradication efforts by cutting and burning the infected plants/trees have mostly failed. At this present juncture there are no chemical management options for control.

Sirex wood wasp – (Sirex noctilio) a species of horntail native to Europe, Asia, and North Africa is an invasive species in other realms. These include Australia, New Zealand, North and South America and South Africa, where it has become a significant economic pest of pine trees especially Pinus radiata.

The wasp can attack a wide variety of pine species, although some species seem to be more susceptible than others and stressed trees are often attacked. It is believed that this insect was introduced on unprocessed pine logs imported from Europe.

P. radiata were first planted in the late nineteenth century in Australia, Chile, New Zealand and in South Africa during the early 1900’s. Their excellent growth provided the basis for thriving lumber and paper industries. During 1920’s and 30’s the lumber industry stagnated, because the demand for small logs from thinning operations decreased.

Hence thinning ceased which made plantations susceptible to S. noctilio and its associated fungus, Amylostereum areolatum. By 1947, high levels of tree mortality were occurring, primarily in the un-thinned plantations causing devastation to the lumber and paper industries.

Adult sirex wood wasps vary in size from 9 to 36 mm (0.35 to 1.42 in), during oviposition the female will lays 2 eggs often with a mucoid substance and a symbiotic fungus to feed on once hatched.

This mucoid substance is toxic to trees as are the ascospores from symbiotic fungus Amylostereum areolatum a species of crust fungus originally called Thelephora areolata. It was given its current name by French mycologist Jacques Boidin in 1958.

The Asian Longhorned beetle – Anoplophora glabripennis native to eastern China, and Korea has been introduced into the United States, where it was first discovered in 1996. Also in Canada and several countries in Europe including, Austria, France, Germany, Italy and UK.

This beetle is believed to have been spread from Asia in solid wood packaging material. A. glabripennis primarily infest maple, poplar, willow, and elm trees. In the United States it has attacked birch, katsura, ash, planes and Sorbus. In Canada on maple, birch, poplar and willow and in Europe on maple, alder, birch, hornbeam, beech, ash, planes, poplar, Prunus, Sorbus and willow.

The Bronze Birch borer – Agrilus anxius is a wood-boring Buprestid beetle native to North America, numerous in warmer parts of the continent where it thrives. It is a serious pest on birch trees Betula frequently killing them. If this insect came to Europe there would be no hope for Birch forests, as the trees have no resistance against this species of insect; hence the effect on Scandinavia’s Birch industry would be catastrophic.

The Emerald Ash Borer – Agrilus planipennis, a devastating alien pest of ash trees was first detected in Europe in Moscow in 2003. Its outbreak in the cities of Western Russia seriously damaged plantations of Ash trees Fraxinus pennsylvanica introduced from North America.

This alien pest posing a major threat to ash trees all over Europe, has spread to Ukraine and the south of Western Russia. It severely damages the green ash F. pennsylvanica, research indicates that will appear in other European countries soon with the potential to destroy F. pennsylvanica plantations.

The Chinese emerald ash borer often referred to as The green menace found its way to America via international shipping. When it gained its freedom it was greeted with a fresh new ‘smorgasbord’ of North American ash trees Fraxinus americana. To date the amount of devastation to millions of ash trees is now in the tens of millions across 25 states.

European spruce bark beetle – Ips typographus, is a species of beetle in the weevil sub family Scolytinae, they are endemic from Europe to Asia Minor and some parts of Africa. Bark beetles are so named because they reproduce in the inner bark of living and dead phloem tissues of trees. In ideal conditions they can travel up to almost a kilometre (½ a mile) in search of a vulnerable host.

Once the host is located, the adult burrows through the weakened bark in order to build tunnels where they can mate and lay eggs. They release pheromones to attract more individuals to the host tree. Two to five weeks after contamination, they may migrate to another host and repeat the process.

European bark beetles have the ability to spread rapidly over large areas and trees in the genera Picea (spruce), Abies (fir), Pinus (pine), and Larix (larch) are this beetles’ trees of choice. Healthy trees use defences by the production resin or latex, which may contain several insecticidal and fungicidal compounds; that kill or injure attacking insects. However in many cases this form of defence is overwhelmed by this pest. 

The insects (from Latin insectum) mentioned here are hexapod invertebrates, the largest group within the arthropod phylum. They are able to create their own colonies if conditions allow, attacking vulnerable vegetation of all types. At this juncture methods of control are inadequate, the old adage that ‘Prevention is better than cure’ is meaningful. But the devastation of ‘unseen invasion’ only becomes visible when it is too late to react.

What we have mentioned here is but a very brief glance into the world of hexapod invertebrates. In the next article of ‘Unseen invasion’ we continue our discussion on more of these harmful pests that are a constant threat to horticulture and bonsai. Until next time, BW, Nik.

Hi, welcome to Taiga Bonzai, we have written much on pests and disease, which cause problems for bonsai enthusiasts and horticultural communities worldwide. In this article we discuss a candidate that not only kills trees, but is able to create serious problems to humans and domestic animals.

Introduction – the ‘Maritime pine‘ or ‘cluster pine‘ Pinus pinaster is native to the Mediterranean basin covering a large area that includes, Portugal, Northern Spain, Southern and Western France, Western Italy, Croatia, Tunisia, Algeria and Northern Morocco.

It is a hard, fast growing pine containing small seeds with large wings and favours this region’s climate of cool rainy winters and hot dry summers. Pinus pinaster is closely related to Pinus halepensis commonly known as the ‘Aleppo pine‘, because both species share many of the same characteristics and pests.

Pinus halepensis also grows in the Mediterranean region in Malta, Montenegro, Albania and east to Greece, Syria, Lebanon, Southern Türkiye, Palestine, Jordan and Israel.

Both these species are subject to attack from Dioryctria sylvestrella, commonly known as the ‘Pine knot-horn‘ or ‘maritime pine borer‘. It is a member of the Pyralidae family, which occurs naturally in Europe, much of Asia and North Africa. This pest has been discovered as far north as the Arctic Circle, but is more common at lower latitudes where it does the most damage.

D. sylvestrella – is a small mottled brown and white insect with a wingspan of 28 to 35 mm, which flies in a single generation from June to October. The female chooses fast-growing, vigorous host trees on which to lay its eggs. The larvae attack buds, shoots, cones and young stems.

Damaged tissue attacked by the rust fungus Endocronartium allow the larvae to enter the tissues and tunnel under the bark into the phloem. The larvae usually remain close to where they were hatched, but occasionally migrate to other parts of the tree.

Larvae pupate inside a mass of resin mixed with frass (shown below) which they produce and continue to feed within. Their boring activity causes large quantities of resin to flow from the wounds weakening the tree, allowing fungi and other pathogens to gain entry eventually threatening the trees health.

D. sylvestrella was first detected in the UK in 2001 and is different from the three other species in the genus, by the fact that the subterminal line is generally smooth with a single waved kink at its midpoint. In the other three species this line is dentate from the mid-point to the dorsum.

Efforts to control – these species of pine are under threat, young trees have no defence and eventually succumb, older more mature trees are able to withstand the onslaught but are severely weakened.

In Italy the powers that be have thought of several methods to control D. sylvestrella for example, chemical usage. But horticulturists are against such practice, their arguments are that there is little or no control and many claim that an effective chemical solution has yet to be found.

In addition, it is argued that a chemical approach would have serious consequences to the horticultural industry. Because if used its properties become airborne resulting in contamination of other crops including, olive, fruit and vegetable production rendering such unmarketable.

Hence loss of income not only to the horticulture fraternity, but also to the state. Moreover, no one in their right mind would consume contaminated food produce, because of the possible side effects if they are unsure of its origin, which is a stringent mandate of the EU.

Finding a solution – the agricultural sector meaning the farmers and growers are of the consensus that it is virtually impossible to prevent the onslaught of D. sylvestrella. Due to its abundance in the Mediterranean region and its ability to invade.

However, studies on D. sylvestrella behaviour indicate that larvae when ready to metamorphosize are compelled to descend the tree and conceal themselves in the litter at the tree’s base. Therefore, preventing the larvae from doing so seems a logical solution in stemming the birth of the next generation of moths.

Traps have been manufactured that can encircle the trunk capturing the larvae as they descend, which are then disposed of. Although these traps are efficient they cost approximately 30 to 50€ each depending on the region. To some this may appear inexpensive; but in reality it is the opposite because much depends on the amount of trees one has on the land. Hence farmers and growers are designing and constructing their own versions. (shown below)

This homemade version consists of plastic base and wall with a layer of foam affixed to the inner diameter to fit snugly against the contours of the trunk. A hole is drilled into the base where a tube protrudes downward to which a plastic bag containing tree litter is tied on.

The larvae walk around the trap eventually falling down the tube into the bag, when the bag is full the larvae are disposed of. This homemade trap costs approximately 3€ to construct. It can be argued that sometimes even the most simplest of inventions are more effective than expensive chemical alternatives.

D. sylvestrella – is harmful to humans and domestic animals due to its ability to shed toxic hairs (called setae or spines) from its body, which it is apt to do when disturbed. According to James H. Diaz of the National Centre for Biotechnology Information; (NCBI)

“Caterpillars bear highly specialized external nettling or urticating hairs and breakaway spines or setae to defend against attacks by predators and enemies“. “These can inflict serious human injuries ranging from urticarial dermatitis and atopic asthma to osteochondritis, consumption coagulopathy, renal failure and intracerebral hemorrhage.”

There are approximately 12 families of lepidoptera worldwide that are able to inflict serious injuries to humans and D. sylvestrella a member of the Pyralidae family is one of them. Andrea Seldeslachts, Steve Peigneur, and Jan Tytgat in their paper published online 2020 May 30. ‘Caterpillar Venom: A Health Hazard of the 21st Century’ states that;

“Depending on the family and species involved, some toxins provoke local urticating dermatitis, a burning sensation, allergic reactions, respiratory system problems and/or ophthalmia nodosa, whereas others cause systemic effects, including hemorrhagic syndrome, acute kidney injury and/oral phalangeal periarthritis.“

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7345192/

With domestic animals, being inquisitive is their natural bent, prone to sniffing or licking: The effect of the toxic venom from the hairs (setae or spines) of D. sylvestrella has what only can be classed as a devastating tragic misfortune, in that there being no antibiotic treatment available at this juncture.

These animals are at risk with the most vulnerable part being the snout a wet fur less surface around the nostrils of the nose called the rhinarium. If this is infected by venom the consequences are severe; hence contact with D. sylvestrella larvae should be avoided at all cost.

As we have stated pests and disease are a major problem in today’s world which have been highlighted through our recent articles. Not all can be attributed to mankind’s actions, but many can – we have problems of varying degrees that require urgent attention; failure to address it will only lead to escalation. Until next time, BW, Nik.

Hi welcome to Taiga Bonzai, in this article we discuss poisonous lepidoptera with arguably the Monarch Butterfly Danaus plexippus and Pipevine Swallowtail Battus philenor being the most well known.

Introduction – although the Monarch and Pipevine butterflies and a large variety of moths are toxic. It is the larval stage (caterpillars) where they are most dangerous to humans, animals and a vast variety of trees, shrubs and horticulture in general, due to the huge devastation they cause.

Caterpillars of most species eat plant material (often leaves), but not all; some (about 1%) eat insects, and some are even cannibalistic. Others feed on animal products. For example, clothes moths feed on wool, and horn moths feed on the hooves and horns of dead ungulates.

Caterpillars are typically voracious feeders and many of them are among the most serious of agricultural pests. In fact, many moth species are best known in their caterpillar stages, because of the damage they cause to fruits and other agricultural produce. Whereas the moths are obscure and do no direct harm.

Etymology – caterpillars have soft bodies that can grow rapidly between moults. Their size varies between species and instars (moults) from as small as 1 millimetre (0.039 in) up to 14 centimetres (5.5 in). Some larvae of the order Hymenoptera (ants, bees, and wasps) can appear like the caterpillars of the Lepidoptera. Such larvae are mainly seen in the sawfly suborder.

However while these larvae superficially resemble caterpillars, they can be distinguished by the presence of prolegs on every abdominal segment. An absence of crochets or hooks on the prolegs. (these are present on lepidopteran caterpillars) One pair of prominent ocelli on the head capsule, and an absence of the upside-down Y-shaped suture on the front of the head.

Lepidopteran caterpillars can be differentiated from sawfly larvae by: the numbers of pairs of pro-legs; sawfly larvae have 6 or more pairs while caterpillars have a maximum of 5 pairs. The number of stemmata or simple eyes, sawfly larvae have only two, while caterpillars usually have twelve. (six each side of the head)

Defence – many animals feed on caterpillars as they are rich in protein. As a result, caterpillars have evolved various means of defence. These include defence against physical conditions such as cold, hot or dry environmental conditions. Some Arctic species like Gynaephora groenlandica have special basking and aggregation behaviours apart from physiological adaptations to remain in a dormant state.

Appearance – of a caterpillar can often repel a predator, its markings and certain body parts can make it seem poisonous, or bigger in size and thus threatening, or non-edible. Some types of caterpillars are indeed poisonous or distasteful and their bright colouring warns predators of this. Others may mimic dangerous caterpillars although they are not actually dangerous.

Many caterpillars are cryptically coloured and resemble the plants on which they feed. An example of caterpillars that use camouflage for defence is the species Nemoria arizonaria (shown below). If the caterpillars hatch in the spring and feed on oak catkins they appear green. If they hatch in the summer they appear dark coloured, like oak twigs.

Chemical defences – more aggressive self-defence measures have evolved in some caterpillars. These measures include having spiny bristles or long fine hair-like setae with detachable tips. These cause serious consequences as described in the previous article. (Unseen invasion 4 the ‘Pine knot-horn‘ or ‘Maritime pine borer‘ )  

Moreover, venom which is among the most potent defensive chemicals in any animal is produced by the South American silk moth genus Lonomia. Its venom is an anticoagulant powerful enough to cause a human to hemorrhage to death. In Brazil 354 cases were reported between 1989 and 2005 with lethality ranging up to 20% with death caused most often by intracranial hemorrhage. This chemical is being investigated for potential medical applications.

These toxic species including the Cinnabar moth Tyria jacobaeae and monarch Danaus plexippus caterpillars, usually advertise themselves with the danger colours of red, yellow and black. Any predator that attempts to eat a caterpillar with an aggressive defence mechanism will learn and avoid future attempts.

Caterpillars cause much damage, mainly by eating leaves. Such damage is enhanced by monocultural farming practices, especially where the caterpillar is specifically adapted to the host plant under cultivation. For example, the Cotton bollworm, Helicoverpa armigera is a major pest of cotton Gossypium spp. maize, Zea mays, pulses, Fabaceae tomatoes, Solanum lycopersicum and sorghum bicolour throughout most of the world.

This species of moth is a recent arrival in the Americas where it is rapidly spreading. It has documented resistance to 49 pesticides and is one of the most polyphagous and cosmopolitan pest species. Caterpillars have been the target of pest control through the use of pesticides, biological control and agronomic practices.

Such approaches are defeated over time via the evolution of resistance mechanisms in the insects, many species have become resistant to pesticides. Until next time, BW, Nik.

Hi, and welcome to Taiga Bonzai, in this post we continue our journey bringing to light the catastrophic failures of mankind’s idiosyncratic actions.

Introduction – according to the Botanical Gardens Conservation International (BGCI) and its network of 500 member organisations, there are 60,065 species of trees in the world; Many are rare and threatened with extinction.

If we multiply the number of tree species with the number of known pests and disease all with different triggers, the statistics would not only be bewildering but also incomprehensible. Here we highlight more increasing problems the world has to face beginning with a few examples of the many deadly diseases, for which at this juncture there is little or no control.

Disease – Armillaria Root, according to Guido Schnabel of the Clemson University School of Agricultural, Forest and Environmental Sciences. “Armillaria root rot caused by the fungus Armillaria tabescens wreaks havoc on rootstocks, killing young and old peach and cherry trees before spreading to neighbouring trees.” “Between 1987 and 1992 Armillaria root rot caused an estimated $3.86 million to the peach industry and between 2000 and 2002, more than $1.5 million in damage to the Georgia peach industry.”

The first symptoms of an Armillaria infection are chlorotic leaves, stunted growth and sudden collapse of shoots. An obvious sign that infection is there due to the presence of clusters of mushrooms around the base of an infected plant. Fungi sprouting from an A. mellea infection are honey-coloured to dark brown and have a domed cap. “Depending on species, the mushrooms may or may not have an annulus around the stalk or caps that are more disc-shaped.”

This devastating disease can be caused by other Armillaria species including, A. mellea a the primary pathogen in northern states causing premature peach tree decline. The potential for significant annual losses in Michigan, is due to the predominant fungus A. ostoyoe found in tart cherry orchards. There is no ‘silver bullet’ solution to protect trees and Armillaria infections have taken many prime orchard sites out of production causing a huge loss of revenue.

Anthracnose – high on the list of devastation is widespread and considered an important disease in most countries. It is caused by a group of fungi in the genus Colletotrichum, that attacks leaves, twigs, flowers and fruits of a great number of tree and shrubs.

Apple scab is a common disease of apple and crab apple tree varieties, as well as Mountain ash Sorbus and pear. It is caused by a fungus Venturia inaequalis that infects leaves and fruit, leaving the latter unsuitable for consumption. Leaf spots are olive green at first, later turning dark brown to black. Infected fruit turns colour in a similar fashion, ending up brown, corky and deformed.

Thousand canker disease – affects many plants including walnuts Juglans sp. It is mainly found in the Western United States however, black walnuts trees in Tennessee were found to be infected in the summer of 2020. It is vectored by walnut twig beetles Pityophthorus juglandis and forms small cankers around their galleries.

As time progresses these small cankers coalesce to girdle branches and stems, trees can be infected for years before symptoms become visible for example. Foliage in the upper branches of declining trees wilt and become yellow. Once a tree begins to decline it is often dead within a few years and at present there are no chemical management solutions to control the disease.

Thus far we have given examples (albeit in brief) of the devastation caused by some of the many thousands of insects and disease. Adding more examples would probably substantiate the argument further, but this task has already been accomplished. In the book ‘Taiga Bonzai – Simplifying The art’ (Revised Edition), where 2 chapters reveal extensive information on these subjects, c.13 concentrates on ‘Pest and Disease’ and c.14 discusses ‘Toxicity’.

We now turn our attention to plants required for our consumption namely fruit and vegetables starting with one of the world’s oldest fruits the humble apple. The bureaucracy over production and the controversy surrounding it including the diseases that attack various species of this particular fruit.

The apple – Malus domestica, its ancestor Malus sieversii originated in Central Asia 4 thousand years ago. Today there are 7,500 apple varieties throughout the world – 2,500 of which are grown in the United States. In the 2019/2020 crop year, China was the leading producer of apples, it’s production amounted to 41 million metric tons. The European Union came in second place with approximately 11.48 million metric tons.

The UK has been producing apples since the Roman occupation (AD 43 to AD 410) however, production is now in serious decline due to bureaucracy and trade problems with the EU. Hence growers are given payments to burn their orchards.

Natural England and the National Trust claimed 60% of England’s orchards had disappeared since the 1950s and have launched a £500,000 project aimed at halting the decline. The crisis has been even worse in some areas such as Devon, which has lost almost 90% of its orchards.

According to David Bullock, the head of nature conservation at the National Trust, “Traditional orchards have been disappearing at an alarming rate. We are in real danger of losing these unique habitats.” (https://www.theguardian.com April 2009)

The orchard – apple trees need space to grow, dwarf varieties require a minimum of 5m, standard trees need a distance of 9 to 11m. But this distance is inadequate because, as the trees mature they spread out, thus the risk of cross contamination from bacterium and fungal spores increases.

In 2017 the total area harvested in the world for apples was 4,933,841 hectares. But, apples are not the only fruit produced, other varieties include apricot, pear, peach, plum and damson. Hence the land mass required increases – these varieties predominantly cultivars are also susceptible to attack, thus the orchard becomes the playground for disease.

Such diseases include: Fire Blight a contagious disease affecting apples, pears, and some other members of the family Rosaceae. It is a serious concern to apple and pear producers and is believed to be indigenous to North America, from where it spread world-wide.

Powdery mildew Podosphaera leucotricha a fungus that forms a dense white fungal growth (mycelium) on the host tissue affecting leaves, buds and shoots. Black Rot and FrogEye Leaf Spot Botryosphaeria obtusa attack fruit, leaves and bark of apple trees. Phytophthora Rot a soil-borne fungal disease by the pathogen Phytophthora sojae causes seed rot and attacks roots and stems; trees infected by such pathogens are usually destroyed.

However, there are apple tree varieties that are said to be disease resistant for example, Liberty, Freedom, Dorsett Golden, Enterprise, Goldrush, Pristine, Arkansas Black and Williams Pride which are American cultivars. European apple trees include, Topaz, Herefordshire Russet and Otava, but can the claims of being disease resistant to all insects and pathogens be substantiated – in short the answer is probably not.

Arguably much depends on a particular climate zone; arid, humid, wet and cold. Moreover, these zones harbour other pests for example, the Round headed apple tree borer, European red mites, Red banded and oblique banded leaf rollers, Rosy aphids, Woolly aphids, Green fruit worms, Leafhoppers and Japanese beetles. Until next time, BW, Nik.

Hi welcome to Taiga Bonzai, in this post we continue our discussion on pests and disease that effect all horticulture in general including bonsai.

Introduction – the coming of winter in the northern hemisphere does eradicate some of the unwanted problems due to lower temperatures. But not all, there are those whom are able to hibernate. In temperate zones these problems remain and are often difficult to eradicate.

Biotic diseases – are caused by living organisms, fungi, bacteria and pathogens left by viral infected insects for example, the ‘Red band needle blight’ Dothistroma that affects conifers mostly pines, causing needle loss eventually killing the tree. Ash dieback affects Ash trees and is caused by the fungus Hymenoscyphus fraxineus. This fungus blocks the tree’s water transport system, causing leaf loss and ultimately dieback of the tree’s apex or crown.

Horse chestnut canker a bacterium species known as Pseudomonas syringae pv. causes extensive bleeding areas on tree stems. Phytophthora austrocedri affects Junipers causing dieback of foliage, stem and collar lesions and eventually death.

Biotic diseases usually appear on random plants but, can effect different plants with various levels of severity often with visible signs of disease for example. Fluffy masses of mould, orange pustules and round leaf spots, wet or water-soaked lesions and irregular shaped leaf spots.

Viruses often cause cankers and irregular colour changes such as mosaic patterns on leaves or unusual foliage colours for example, reddening of the leaves. Nematodes, a microscopic worm are also classified as a biotic disease causing root rots and irregular root growth. Arguably biotic diseases are part and parcel of nature’s rich tapestry something we have to accept.

Abiotic diseases are the result of non – living causes, the result of human activity – herbicides, pollution, an excess or lack of nutrients that plants require for growth. For example, Chloride (C1-) and Magnesium (Mg+2) are both essential nutrients important for normal growth. However, excessive concentrations of these nutrients may harm a plant with chloride being responsible for foliage damage as opposed to magnesium.

High concentrations of MgC12 ions in the soil may be toxic insomuch that they are able to effect and alter water relationships, meaning the plant can not accumulate water and nutrients naturally. The effect of chloride in the conducting system causes an accumulation of necrosis in leaves or needles and where dieback first occurs. Leaves are weakened or killed, which can lead to the death of of a tree.

A common cause of necrosis is brown, dead or wilted leaf tips and yellowing of older leaves. If this is the case, then the plant should be removed and cleaned immediately by washing the whole tree including the root ball with distilled water. Any decaying foliage should be removed and the container or pot should also be cleaned and the plant re-potted in a fresh soil medium.

When dried out particles of (MgC12) become airborne they travel great distances. Contaminating all they come in contact with especially trees and shrubs, be they of natural proportions or bonsai and also back into the soil where they react causing chloride toxicity.

Symptoms associated with exposure to de-icing, salt sprays, aerosols or road dust differ from root absorption. The side of the tree facing the road may exhibit more damage, foliage will have surface deposits of salt crystals or dust. These usually appear in a distinct pattern affecting other plants that are in close proximity.

One of the major causes of excessive concentrations of (MgC12) is due to the de-icing of highways, streets, roads and pavements via the use of granulated magnesium chloride. (MgC12) This is applied during the winter months and is different to halite road salt. (sodium chloride NaC1) Liquid (MgC12) solutions are also applied to non-paved roads during spring and summer months for dust suppression.

Pest and disease problems in bonsai are often the result of more than one cause. These are referred to as complexes for example, aphids and leafhoppers often spread various plant diseases in the process of feeding.

Weak plants in abiotic conditions (nutrient deficient soils) are more susceptible to attack by various diseases and insects. In such cases it is not enough to simply treat a tree with pesticide or fungicide, all cases of the complex should be addressed to ensure good health and vitality in the tree’s development.

Magnesium chloride according to the powers that be, this chemical be it in granulated or liquid form is mandatory for de-icing and suppression of dust. But, when the snow has gone and the roads and pathways have dried, (MgC12) still remains on the surface.

When the machines start sweeping these areas, the dust becomes airborne – an ill wind. The area where our bonsai trees are housed is open to the elements and prone to (MgC12) residue. This presents a problem in having to be constantly cleaning. Arguably there should be a consultation regarding (MgC12) usage, because the damage it causes to all flora and to the buildings it disfigures. Until next time, BW, Nik.

Hi welcome to Taiga Bonzai, in this post we discuss horticulture in other parts of the world, where nations are having difficulty in controlling pests and disease.

Introduction – horticultural methods in general have two schools of thought when growing crops, either by (a) conventional methods (organic) or (b) genetically modified organisms. (GMO)

Conventional – is an agriculture term referring to a method of growing edible plants such as fruit and vegetables without the use of synthetic chemicals. (fertilizers, pesticides, antibiotics, hormones)

GMO – method of cultivation often use fertilizers and pesticides which allow for higher yield, out of season growth, greater resistance, longevity and greater mass.

Organic versus GMO – people have very strong opinions on which method of horticulture is better. Some advocate a preference for organic because it is healthier, tastes better and growers refrain from using pesticides. But there are negatives to this approach, fruit and vegetable yields will suffer due to the inevitable onslaught of pests and disease during the growing season for example.

Many insects attack Brassica species the most common are diamondback moth Plutella xylostella also called cabbage moth, tobacco cutworm, aphids and many others. Hence more is planted to compensate for the loss and although organically grown food is preferable and more beneficial to consumers because it does not contain chemicals; it is more expensive.

Whereas GMO use seeds that have been genetically modified to grow plants that have a faster growth rate, higher yields, are said to be pest and disease resistant and are cheaper to buy nonetheless, there are negatives to this approach.

The use of synthetic pesticides and fertilizers on fruit and vegetables may eradicate many known pests and disease, but also kills insects that are beneficial for example. The lady bird beetle Coccinellidae a predator extremely proficient in eradicating aphids and scale colonies.

Other nations – ‘Nilaparvata lugens’ the brown plant hopper (BPH), is a planthopper species that feeds on rice plants Oryza sativa L. These insects are among the most serious pests of rice a major staple crop for more than half the world’s population. 

They damage rice directly through feeding and also by transmitting two viruses, rice ragged stunt virus and rice grassy stunt virus. Up to 60% yield loss is common in rice cultivars attacked by this insect. BPH is found throughout Australia, Bangladesh, Bhutan, Burma (Myanmar), Cambodia, China, Fiji, India, Indonesia, Japan, North and South Korea, Laos, Malaysia, India, Nepal, Pakistan, Papua New Guinea, Philippines, Sri Lanka, Taiwan, Thailand, and Vietnam. 

The brown plant hopper is dimorphic and can be either ‘macropterous’ (long wings) or ‘brachypterous’ (short wings) forms. The macropterous forms are migrants and invade new fields/paddies. Adults usually mate on the day of emergence, and the females start laying eggs from the day following mating. Brachypterous females lay 300 to 350 eggs, whereas macropterous females lay fewer eggs; the eggs hatch in about six to nine days.

In Asia, India has the largest area for rice cultivation occupying 29.4 % of the global area, but has the lowest yield. The conventional paddy growing practices are in crisis due to social, biological and technical setbacks. Yet there is a growing demand for rice due to ever burgeoning population.

Rice demand in 2010 was estimated to be 100 million tonnes and this would increase by 50% in 2025 to assure food security in the world’s rice-consuming countries. However, with water becoming scarce many fields are drying out and coupled with increasing infestations of Nilaparvata lugens causing yield loss, it will difficult to fulfil the demand.

The cotton bollworm Helicoverpa armigera is a major pest of cotton Gossypium spp. maize, Zea mays, pulses, Fabaceae tomatoes, Solanum lycopersicum and sorghum bicolour throughout most of the world. But has only recently arrived in the Americas where it is rapidly spreading. It has documented resistance to 49 pesticides and is one of the most polyphagous and cosmopolitan pest species. 

This species of Lepidoptera is found in Asia, Australia, New Zealand, Europe, Africa and South America. The adults emerge from the soil in the first 3 weeks of May and 2-6 days later oviposition begins. This is a period lasting between 5-24 days. Within this time frame, a female may lay up to 3180 eggs, up to 457 in 24 hours singly and mainly at night on various crops.

Including, chickpeas, cotton, maize, okras, tobacco, tomatoes; when temperatures rise to 25°C, the eggs will hatch in 3 days and larvae immediately begin crop infestation and devastation. When fully fed, the larvae descend to the soil after 1-7 days pupate in an earthen cell 2-8 cm below the surface.

Pesticides – of which there are many used to control Helicoverpa armigera including, Lambda Cyhalothrin, Chlorpyriphos, Cypermethrin Acetamiprid and Profenos Cypermethrin. But as stated previously this pest has documented resistance to 49 pesticides. Moreover, we have pointed out many pests and disease cannot be eradicated.

In 2020 global pesticide usage was estimated to increase from 2 million tonnes to 3.5 million tonnes with China being the main user 1,763,000 tons followed by America 407,779 tons, Brazil 377,176 tons and Argentina 196,009 tons. One may argue that pesticides are beneficial for crop production, but extensive use of pesticides can possess serious consequences because of their bio-magnification and persistent nature.

Diverse pesticides directly or indirectly pollute air, water, soil and overall ecosystem which cause serious health hazards for living beings. One only has to look at the tens of thousands of lawsuits filed against Monsanto (now part of Bayer) over their chemical ‘Roundup’. Until next time, BW, Nik.

Hi welcome to Taiga Bonzai, in this post we look at the points of view of others whom have various opinions on how to tackle the ever increasing problem of pests and disease. However, the course of action taken by individuals, communities and/or sovereign nations, results in stiff opposition and the threat of sanctions. Due to bureaucracy and petty mindedness.

Introduction – thus far we have highlighted the many factors responsible for the present situation, that we now face all of which are of our own making. The financial cost of it all to date has been phenomenal and will continue to rise exponentially. Meeting our own needs without compromising the ability of future generations, will be difficult; bringing us to the point of no return.

United Nations FAO – at a conference in Rome 3rd April 2019, Bukar Tijani assistant director general for the Food and Agriculture Organisation of the United Nations (FAO) Consumer Protection Department stated that. “With increased trade and travel, the risks of plant pests spreading into new areas across borders is now higher than ever before. Each day we witness a shocking number of threats to the well-being of our plants and by extension to our health, environment and economy.”

The FAO estimates that annually between 20 to 40 percent of global crop production is lost to pests. Each year plant diseases cost the global economy around $220 billion and invasive insects around $70 billion. “Many farmers and governments grapple with warding off highly destructive pests and diseases that are – on top of everything else – also new to them. The International Plant Protection Convention IPPC provides them with the tools and knowledge to keep their plants healthy and prevent pests from jumping borders.” added Tijani.

New IPPC standards adopted – 1. fumigation methods, this is in response to growing concerns over fumigants that can be harmful to human health and the environment. The standard requirements for temperature, duration, fumigants and quantity have been set.

2. Diagnostics protocols that describe procedures and methods for the official diagnosis of six pests. Including the oriental fruit fly Bactrocera dorsalis and Xylella fastidiosa, ensuring a correct diagnosis is essential to catalyse rapid actions to manage the pests.

B. dorsalis has affected trees such as avocado, banana, guava and mango in at least 65 countries. In Africa, import trade bans due to oriental fruit fly infestations cause annual losses of around $2 billion. Xylella fastidiosa is a deadly bacteria that attacks economically important crops such as olive, citrus, plum trees and grapevines.

Since 2015, it’s been rapidly spreading from the Americas to Europe and Asia. Once the disease infiltrates a plant, it is there to stay, it starves the plant of water until the plant dies or becomes too weak to grow fruit.

X. fastidiosa costs $104 million per year in wine losses in California and in Italy the bacteria has led to the decline of 180,000 hectares of olive groves, destroying many centuries-old trees. A loss of €390 million over three years. X. fastidiosa constitutes a threat not only to Italy but to all the Mediterranean region’s economy.

X. fastidiosa is not known to be in the UK however, there have been outbreaks of the disease in mainland Europe in France, Italy and Spain. Portugal confirmed its first case in 2019 on lavender. Hence, the UK Government is concerned on how to prevent the disease being accidentally brought into the country on imported plants. In 2020 Lord Framlingham a Conservative peer asked the Government what the UK’s regulations are regarding X. fastidiosa.

UK regulations – measures were to strengthen the protection of plants from certain pests and diseases, including Xylella. They were made under article 52 of the EU Plant Health Regulation. Allowing the UK to take additional temporary national measures, providing they inform the European Commission and put forward a technical case to request EU measures against a specific pest. But those measures have not or will not be introduced in time to mitigate the risk concerned.

Moreover, the UK Government has argued that current EU emergency measures on Xylella do not address risks highlighted in the UK’s pest risk analysis on the disease.

In particular, it is not clear if or when the EU emergency measures will be reviewed to address these risks and ensure a greater degree of assurance of disease freedom. In relation to plants of those species being moved in the EU and introduced from third countries. As such, there remains an unacceptable level of pest risk and this instrument introduces national measures under article 52, in the absence of EU requirements.

The European Commission’s response – on 4 June 2020, the EU said that it informed the UK the new national measures. “That go beyond the existing requirements, are not supported by most recent scientific justification and are disproportionate.” It stated that the UK “should amend it’s official control regulations of 2019, by removing the amendments concerning X. fastidiosa and Ceratocystis platani which were made to those regulations by the UK in 2020.”

On 19 June 2020, Department for Environment, Food and Rural Affairs (Defra) stated that the UK disagreed with the European Commission’s conclusions and that it was disappointed. “The opportunity has not been taken to extend the UK measures across the EU, providing enhanced protections for the EU’s member states.” Defra argued “that the biosecurity threat regarding the pests had not changed and the rationale for introducing stronger requirements remained.”

The department said it continued to encourage stakeholders and industry to “employ risk management practices which maintain the robust protection and assurance that the Defra regulations provide.” 

Defra also stated that The Animal and Plant Health Agency and the devolved administrations will continue to carry out intensive inspections of imported plants. Taking account of risk factors such as origin, presence of insect vectors and suspect symptoms. “We will keep the need for any further actions under review in light of the ongoing risk situation, including developments in the EU and the results of our own surveillance.”

The Royal Horticulture Society (RHS) is also in agreement, plant health is increasingly under threat. Climate change and human activities have altered ecosystems, reducing biodiversity and creating new niches where pests and diseases can thrive. At the same time, international travel and trade has tripled in volume in the last decade. The result is that pests and diseases can quickly spread around the world causing great damage to horticulture, crops and the environment.

New statutory controls on importing plants and plant products into the UK to safeguard plant health. “Meaning that plant material entering the UK will require a phytosanitary certificate (PC); the EU plant passport is no longer valid in the UK.” 

The U.S. DEPARTMENT OF AGRICULTURE – (USDA) state that world trade has significantly increased over the years to meet the growing demand and at this moment in time, America is the only country to import more than it exports.

USDA researchers Michael Livingston, Craig Osteen and Donna Roberts argue “That this increase in agricultural imports raise the risk of inadvertently introducing foreign pests and diseases.” which has been proven to be the case. For example, the emerald ash borer and Asian long horned beetle introduced in the 1990’s are creating serious damage to trees in the Northeast and Great Lakes States.

More recently Ralstonia solanacearum, a bacterial pathogen that damages potatoes, eggplant, tomatoes and other horticultural products was detected on greenhouse geraniums imported from Kenya and Guatemala. “The cost of foreign pests and diseases can also include the temporary loss of export markets, such as when Japan, Korea and other countries suspended imports of U.S. beef when bovine spongiform encephalopathy (BSE) was detected in an imported cow in December 2003.”

Studies by the National Plant Board, the Government Accountability Office, the Office of Technology Assessment and others, report that foreign pests and diseases cause billions of dollars of economic losses to U.S. agriculture each year, while also adversely affecting ecosystem values and services.

These cost estimates include sizable public expenditures, including emergency funding to address new pest or disease threats and outbreaks. Today, 21 Federal agencies are responsible for some aspect of managing foreign pests and diseases in the United States.

USDA’s Animal and Plant Health Inspection Service (APHIS) has by far, the leading role accounting for about $9 out of every $10 that the Federal Government spends annually on prevention and control of foreign pests and diseases. Annual expenditures for APHIS programs ranged from $1.1 to $1.5 billion between 2003 and 2007, including emergency expenditures for programs such as increased BSE surveillance in 2004-06 and the introduction of import bans.

In evaluating such bans, economists try to measure the benefits of imports against the management production market and/or resource costs that might be associated with an outbreak of a disease or pest. Studies show that this varies on a case-by-case basis. Import bans have reduced total welfare in some cases, because the cost of disease establishment was out weighed by the consumer benefits from imports.

For example, APHIS estimated that the annual net benefits of replacing a long standing ban on imports of Mexican avocados with more targeted phytosanitary measures totalled about $70 million. Providing analysis support for USDA’s decision to grant Mexico full access to the U.S. market in 2007.

A recent study by an ERS economist, which examined options for policies to reduce the risk of entry of the Mediterranean fruit fly, (medfly) illustrates how economic analysis can inform public decision making. The medfly is a serious pest for many fruit and vegetable crops and is known to exist in 65 foreign countries. (hereafter referred to as quarantine countries)

APHIS allows imports of fresh produce from these countries only if they have been treated to eliminate medfly larvae. Currently, eight treatments are approved for the medfly. One of the most widely used is cold treatment, under which produce imported for fresh consumption must be refrigerated according to specific schedules (temperature-duration combinations) before allowed entry into U.S. markets.

In the next article we look at how other nations are dealing with the problems of pests and disease. Until next time, BW, Nik.

Hi welcome to Taiga Bonsai, in this article we continue our discussion with a look at what other nations are doing to prevent the spread of pests and disease.

Introduction – in Australia pests and disease are a significant social, economic and environmental burden for the nation. They affect primary production, productivity, access to export markets, public health and amenity. In addition, conservation of biodiversity, natural and built environments suffer.

These effects can reveal themselves through increased costs of production, loss of or restrictions to export trade, reduced tourism, loss of biodiversity, greater public health costs and reduced public amenity.

Some introduced pests and diseases for example, animals (rabbits, foxes, carp) are often infected with Johne’s disease, a chronic, contagious and often fatal disease of cattle, sheep and goats, caused by the intestinal bacterium Mycobacterium. Plant pests including blackberry and mimosa are infected with the potato cyst nematode that has become established over time in Australia with no prospect of eradication.

Some of these pests and diseases are reported to have economic, environmental or social impacts of national significance. Consequently, a nationally coordinated approach may be required. Given the shared responsibilities for their management among stakeholder groups. The effective management of nationally significant threats requires clarity of policy direction, priority, roles and responsibilities.

Governments at the national, state and territory levels; industry and individual landholders, have invested jointly in pest and disease management over many decades. These investments have been made across the biosecurity continuum onshore, at the border and offshore.

Managing biosecurity is critical to a sustainable and productive agricultural sector and healthy environment. It protects farmers and the environment from the impacts of serious pests and diseases. Which can significantly increase the costs of production and market access, domestically and internationally and affect the native flora and fauna. Effective management of established pests and diseases also assists Australia to meet its obligations with respect to international trade.

Under the Coalition of Australian Governments Intergovernmental Agreement on Biosecurity of 2012, states are implementing reforms to strengthen the national biosecurity system. The aim is to deliver more effective and sustainable biosecurity outcomes for all. One focus of this agreement is to establish a national framework for managing established pests and diseases of national significance. Consistent with emerging policy across numerous portfolio areas, there are opportunities to:

• “move away from government enforcement as a primary means of managing the impacts of established pests and diseases
• adopt approaches in which the nature and magnitude of investment is determined by the extent and balance of public and private benefits
• focus public investments on strategic functions including addressing market failure
• promote more collaborative working arrangements between government and those stakeholders directly affected by established pests and diseases rather than have stakeholder groups acting in isolation.”

World Trade Organisation (WTO) – Kamal Saggi and Mark Wu in their World Trade Review Volume 16 Issue 2nd April 2017, pp. 279 – 302, state “Global exports of agricultural goods exceeded $1.7 trillion in 2014, with food accounting for over 80% of the total value.” “Such cross-border movement of food and agricultural goods helps ensure the sustenance and economic well-being of billions around the world. Yet, trade rules for agriculture remain an extremely sensitive issue. This is particularly the case when agricultural imports carry the threat of disease.”

“Not surprisingly then, under the rules of the World Trade Organization member countries are allowed to restrict the importation of agricultural products from diseased regions. However, if governments could do so without limitation then this freedom could quickly devolve into a protectionist excuse that has the potential to seriously thwart trade liberalisation in the agricultural sector.”

Saggi and Wu argue that relevant WTO rules therefore, “must seek to balance two competing objectives providing sufficient flexibility for sovereign governments to regulate imports from diseased regions,” while simultaneously culling out protectionist measures for which the threat of diseased imports simply serves as an excuse for keeping imports at bay.

“Getting this balance right is tricky, in 1994, Uruguay Round negotiators drafted the Agreement on Sanitary and Phytosanitary Measures (SPS Agreement) to spell out in detail the requirements that a WTO member must follow when seeking to ban or restrict imports of agricultural goods.”

We know that every country has its own endemic pest and disease problems, some have invaded other lands by wind and wing a natural phenomenon and also by the hand of man resulting in consequences on a catastrophic scale. which we have little chance of eradicating.

Because (a) we cannot see the problem until it is too late and (b) we lack the technical knowledge of how to arrest the situation. Yes there are many chemical solutions that can be used, but not all are effective especially with the many of pests and diseases we have mentioned in these articles. Moreover, these chemicals are not only dangerous to human health they eek into the soil killing microbes, earthworms, nematodes and other much needed creatures.

It can be agreed that commerce is an important factor in the modern world, but our attention to detail has been lackadaisical to say the least. Countless goods have been exported in infested packaging worldwide – the pests and disease have escaped multiplying in their millions ravaging agriculture and forestry. Many nations are now spending billions to eradicate pests and disease and the cost is escalating, whilst poorer under developed countries whose national GDP is practically non-existent suffer in silence and starve.

As stated “whatever course of action deemed necessary taken either by individuals, communities and/or sovereign nations, there will always be stiff opposition and the threat of sanctions of one description or another.” Yet nations continue to blame each other instead of looking closer to home. It is imperative that we find common ground to seek solutions to curb the never ending invasion of pests and disease world-wide, failure to do so will result in devastating consequences.

As a species we rely on an array of factors vital to our very existence including technology, transport, housing, energy, education, medicine, clean water, forestry and agriculture for our immediate needs. If these are not protected then we face the inevitable – a world of devastation, dire water scarcity, where famine and pestilence rampage amok. Is this a world we want our children’s children and their descendants to inherit?

We wrote this series of articles to highlight the problems mankind has created and battled with for aeons, a predicament that is now escalating unprecedentedly. In the next article we look at the possible reason and cause why we have arrived at this juncture. Until next time, BW, Nik.

Hi welcome to Taiga Bonzai, in this article we discuss some of the possible reasons of why we are unable to stem the onslaught of pests and disease.

Introduction – the increasing problem of invading pests and disease devastating agriculture, horticulture, natural woodlands and forests across the globe. A problem that is now making headlines around the world.

The decline – over the last few decades there has been an increasing decline in the insect population. Disappearing are many helpful predators including, Ladybugs Coccinellidae, Green Lacewings Chrysopidae, Honey Bees genus Apis, Praying Mantis family Mantidae, Spiders family Arachnida, Ground Beetles family Carabidae, Soldier Beetles family Cantharidae, Assassin Bugs family Reduviidae and Robber Flies. Asilidae

These insects are part of the food chain they eradicate unwanted pests including aphids, scale, mealy bugs and saw fly and in turn are the main resources for many birds, small mammals, fish, reptiles and other creatures.

Moreover, they are an important key for human food production because, many crops depend on insects for pollination leading to fruit and seed production. Insects play a very important role in decomposing organic matter allowing nutrients to return to the soil and support the on coming crop season. Therefore, in terms of insect ecological importance, a sharp decline in their abundance is of great concern.

The arguments – here are the points view from others whom are mindful of this issue. Will de Freitas asks if we are facing insect Armageddon he states that, “A recent study found that German nature reserves have seen a 75% reduction in flying insects over the last 27 years. The researchers involved made stark warnings that this indicated a wider collapse of the general insect population that would bring about an ecological catastrophe if left unchecked.” (article – October 25, 2017 – The Conversation)

Damian Carrington Environment editor for The Guardian in his article (10th February 2019) argues that “The world’s insects are hurtling down the path to extinction, threatening a catastrophic collapse of nature’s ecosystems.”

“More than 40% of insect species are declining and a third are endangered, the analysis found. The rate of extinction is eight times faster than that of mammals, birds and reptiles; the total mass of insects is falling by a precipitous 2.5% a year, according to the best data available.”

In the February 2020 journal Biological Conservation no, 242 (a leading international body of scientists in the discipline of conservation science) Editor in chief Vincent Devictor of the Institut des Sciences de L’Evolution de Montpellier, France stated that. “We are causing insect extinctions by driving habitat loss, degradation and fragmentation, use of polluting and harmful substances. The spread of invasive species, global climate change, direct over exploitation and co-extinction of species dependent on other species.”

Devictor goes on to say that “With insect extinctions, we lose much more than species. We lose abundance and biomass of insects, diversity across space and time with consequent homogenization, large parts of the tree of life, unique ecological functions and traits and fundamental parts of extensive networks of biotic interactions. Such losses lead to the decline of key ecosystem services on which humanity depends.”

According to http://www.magnificentmeadows.org.uk “The UK’s remaining rich grasslands now cover a minute fraction of the area they once covered, even relatively recently in the early 20th Century. There were once natural wildflower meadows in every parish – today only 2% of the meadows that existed in the 1930’s remain. Nearly 7.5 million acres of wildflower meadow have been lost so far and they are still being destroyed.”

The blame game – these are but a few of the arguments from scientists and conservationists from the many we have researched and from these points of view it appears we have a major situation on our hands. There are many theories as to the decline in insect populations they include, habitat destruction by intensive farming and urbanisation, pesticide use, introduced species, climate change, eutrophication from fertilisers, pollution and artificial lighting; the latter used in huge polyethylene tunnels for intensive crop production.

Yet, despite the scientific evidence provided, globally our performance in instigating effective insect conservation is below par, we need to realise this fact and act accordingly. This would involve more inclusive education, better decisions with land managers and government officials in maintaining unique habitats, across the globe. To have more expansive sustainable agriculture and forestry, improved regulation and prevention of environmental risks and greater recognition of protected landscapes.

But the frailty and idiosyncrasy of human nature is what it is, the world’s heads of state congregate at summits and conferences to find ways to solve problems, each pointing the finger blaming the other for their misgivings when they themselves are equally responsible for the same actions. It is fickleness, bureaucratic hypocrisy by the asinine in an attempt to maintain ‘stability’, (economic, environmental and social or profits, planet, and people) a mind set proposed for the wealthy not the masses.

As the world’s population increases so does the demand for more sustainability in food production. We know that pests and disease from all corners of the globe are a major threat to all countries, resulting in irreversible changes to environments.

Insects are a major component of the tapestry of life and failure to protect them will have dire consequences. Moreover, they are our natural defence in stemming the increasing onslaught. It is now time for heads of state and their minions to refrain from ‘putting their heads in the sand’ and listen to the scientists to prevent a ‘Bug apocalypse.’

Thus far we know the present situation and the problems we now face, but how did it get to this stage? In the next article we look at some of the causes that have created this catastrophe during the last 70 years, until next time, BW, Nik.