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.