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 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.

Statement – towards the end of 2024 we stated that our desire was to move to a new platform, after being with WordPress since 2016. (9 years) We have the new platform and already have been posting articles there. A platform where journalists and academics can post their content with ease. The platform is Substack.com – Taiga Bonzai.com we will post this article on WordPress then we will cease.

Hi welcome to Taiga Bonzai, in this article we revisit the article 62 – ‘New diseases’ 2 due to the comments received and the request for further information.

Introduction – the above mentioned article focussed it’s attention on Fusarium solani, a complex species of at least 26 closely related filamentous fungi in the division Ascomycota, family Nectriaceae. It is the anamorph of Nectria haematococca and a common soil inhabiting mold.

Fusarium solani is implicated in plant diseases as well as in serious human diseases such as fungal keratitis (Summerell, Brett A.; Laurence, Matthew H.; Liew, Edward C. Y.; Leslie, John F. (14 September 2010). (“Biogeography and phylogeography of Fusarium: a review.“)

History and taxonomy – the genus Fusarium was described in the 1930s, by Wollenweber and Reinking who organized the genus Fusarium into sections, including Martiella and Ventricosum, Lesli, John., Summerell, Brett, A. (2006) ^{The Fusarium Laboratory Manual. Ames: Blackwell. pp. 250–254.}

In the 1940s, these were collapsed together by Snyder and Hansen to form a single species, Fusarium solani; one of nine Fusarium species they recognized based on morphological features. 

The current concept of F. solani is as a complex species consisting of multiple, closely related and morphologically poorly distinguishable, “cryptic” species with characteristic genetic differences. There is a proposed concept for the entire genus – widely subscribed by specialists – that would include this complex. (Geiser, David M; Al-Hatmi, Abdullah; Aoki, Takayuki; Arie, Tsutomu (2020-11-17)

Like other species in its genus, Fusarium solani produces colonies that are white and cottony. However, instead of developing a pink or violet centre like most Fusarium species, it can become blue-green or bluish brown. (as shown below) 

On the underside, they may be pale, tea-with-milk-brown, or red-brown. Yet, some clinical isolates have been blue-green or ink-blue on the underside. Colonies are low-floccose, loose, slimy, and sporadic. When grown on potato dextrose agar (PDA), this fungus grows rapidly, but not as rapidly as Fusarium oxysporum. In PDA, F. solani colonies reach a diameter of 64–70 mm in 7 days.

F. solani is found in soil worldwide. However, a given species within the complex may not be as widespread and may not have the same ecology as others in the complex. In general, as a soil fungus, F. solani is associated with the roots of plants and may be found as deep in the ground as 80 cm. It is frequently isolated in tropic, subtropic, and temperate locations, and less frequently isolated from alpine habitats. 

The pH of soil does not have a significant effect on F. solani, but soil fumigation causes an increase in occurrence. F. solani is typically sensitive to soil fungicides. F. solani has been found in ponds, rivers, sewage facilities, and water pipes. 

F. solani has it’s chlamydospores that overwinter on plant tissue/seed or as mycelium in the soil. The pathogen enters the host through developing roots, where it can infect it. After infection, F. solani produces asexual macro and microconidia which are dispersed via the elements. The pathogen can persist in the soil for a decade and if left unchecked can cause complete crop loss.

The fungal pathogen rots the roots of its host plant. It also causes soft rot of plant tissues by penetrating plant cell walls and destroying the torus. It is implicated along with Pythium myriotylum, in pod rot of the pods of groundnuts. 

It can cause damping off, corn rot, and root rot, as well as sudden death of soybeans (SDS). It is a very generalistic fungal species and has been known to infect peas, beans, potatoes, and many types of cucurbits. Symptoms include general plant decline, wilting, and large necrotic spots on tap roots. Recently the pathogen has also done serious damage to olive trees throughout the Mediterranean region.

F. solani is largely resistant to typical antifungal agents. The most effective antifungals in treating F. solani infections are amphotericin B and natamycin; however, these agents have only modest success in the treatment of serious systemic infection.

Effect on humans – as of 2006, there has been increasing evidence that F. solani  can act as a causal agent of mycoses in humans, it has been implicated in the following diseases: disseminated disease, osteomyelitis, skin infection, fungemia, and endophthalmitis. 

Half of human disease involving Fusarium is caused by F. solani and is involved in most cases of systemic fusariosis and corneal infections. In immunocompromised patients, F. solani is one of the most common agents in disseminated and cutaneous infections.

In the southern USA, fungal keratitis has been most commonly caused by F. solani, as well as F. oxysporum. Cases occur most frequently during harvest season as a result of corneal trauma from dust or plant material. Fungal spores come into contact with the damaged cornea and grow.

Without treatment, the hyphae can grow into the cornea and into the anterior chamber of the eye.^] F. solani is also a major cause of fungal keratitis in HIV positive patients in Africa.

An investigation into a meningitis outbreak of 79 cases since October 2022, that had killed 35 people (34 of them women who had undergone cesarean section) in Durango (Mexico city) revealed the contamination of bupivacaine with Fusarium solani in 4 batches, used by an anesthesiologist.

As of June 1, 2023, a multistate outbreak of meningitis due to F. solani was ongoing among patients who underwent epidural anesthesia at two clinics in the Mexican city of Matamoros, Tamaulipas a Mexican state, with a total of 212 residents in 25 US states identified as being at risk, two of whom had died.

There will be more scholarly on new plant disease be it fungal pathogens borne on the wind or wing, or via entomology invasion. We will continue to add them on our new platform Substack.com where you can find us using our name Taiga Bonzai.com. We thank our readers and followers from around the world whom have been with us since 2016, until next time, BW, Nik.