Written by Melanie Bateman, Integrated Crop Management Adviser, CABI Switzerland
As has been mentioned before in this blog, there are a staggering number of chemicals in the world – estimates go as high as 2 million different preparations for sale. This is a lot for regulators in any given country to assess and monitor for safety concerns, especially given the nature of many of the problems associated with pesticides. While symptoms of acute pesticide poisoning become apparent relatively rapidly after exposure, chronic effects such as cancer can be caused by repeated, low level exposure over extended periods of time. For these chronic problems, it is much more difficult to uncover the connections between the chemical and the disease.
International agreements such as the Rotterdam and Stockholm Conventions provide formal channels for information sharing on these issues between countries.
At a recent workshop on pest management and pesticide risk reduction, Mr David Kamangira, Senior Deputy Director in Zambia’s Department of Agricultural Research Services, offered up a suggestion for a grassroots approach for sharing information and staying informed about pesticides. He shared his experience with the “Pesticides-L” mailing list, an online forum for discussions regarding pesticides management issues. Moderated by Dr Andrea Rother of the School of Public Health and Family Medicine of the University of Cape Town, Pesticides-L is open to anyone with an interest in issues related to pesticides. Posts to the list cover topics ranging from research results on human health and environmental effects to policy debates to meeting announcements. The Pesticide-L mailing list is a rich information source and a valuable tool for linking together a global community of stakeholders such as researchers, NGO’s, chemical companies, policy makers, affected individuals, unions, farmers, community groups and government representatives. To subscribe to this list, email ‘email@example.com’.
BBSRC (Biotechnology and Biological Sciences Research Council) and Syngenta funded scientists at the University of York and University of Durham have discovered a gene called AmGSTF1 that plays a key role in controlling multiple herbicide resistance in black-grass (Alopecurus myosuroides) and annual rye-grass (Lolium rigidum). Now the gene that confers resistance has been identified, it is hoped that chemicals that inhibit the gene may be able to be used in future to make herbicides effective against resistant weeds.
Black-grass and rye-grass are widespread weeds which cause problems in cereal and oilseed rape farming. Management using herbicides is becoming increasingly difficult since both black-grass and rye-grass can acquire a single defence mechanism that confers resistance to multiple herbicides- known as multiple herbicide resistance. The genetics of multiple herbicide resistance have been poorly understood until recently, however scientists have now discovered that a gene producing an enzyme called glutathione transferase (GST) is responsible for multiple herbicide resistance. Scientists created transgenic thale cress (Arabidopsis thaliana) plants with the GST producing gene inserted which were resistant. GSTs are known to detoxify herbicides, but project leader Professor Rob Edwards of the Centre for Novel Agricultural Products at the University of York believes that the gene they discovered works as a kind of ‘master switch’ that activates a range of protective mechanisms in the plant. When resistant plants with the GST gene are sprayed with GST inhibiting chemicals, they become susceptible to herbicides. This demonstrates the potential for using GST inhibiting compounds in future herbicide formulations to manage resistant rye-grass and black-grass. These weeds are currently very difficult to manage due to their widespread herbicide resistance.
The United Nations Food and Agriculture Organisation (FAO) has this month warned that Desert Locust (Schistocerca gregaria) swarms are invading cropping areas of northern Sudan. The swarms originated from winter breeding areas on the Red Sea coastal plains and subcoastal areas in northeast Sudan and southeast Egypt. The situation requires close monitoring as more swarms are expected to form in the coming weeks that could move into parts of Sudan and southern Egypt. If no further rains fall and the vegetation dries out, some of these swarms could move into the interior of both countries and also cross the Red Sea to the coast of Saudi Arabia.
Locusts belong to the Acrididae family (in the order Orthoptera which includes grasshoppers and crickets) and when triggered by certain cues such as increased crowding with other locusts have the ability to change their morphology, behaviour and physiology over several generations. This phase change occurs from a solitary to a gregarious phase, eventually causing the locusts to form dense hopper bands and swarms. One of the most serious locust pests is the Desert Locust.
A research team led by the Beijing Academy of Agriculture and Forestry Sciences have produced the complete genomic sequence of watermelon (Citrullus lanatus). It is hoped that the genomic data from this study will shape future research into watermelon genetics and provide a good resource for crop genetics and future plant breeding projects, resulting in improved watermelon cultivars with a greater degree of pest resistance.
The Coffee Berry Borer, Hypothenemus hampei, is a tiny beetle which is widely considered to be the most damaging pest of coffee plantations in the world. Originating in Africa, it is now found in almost all coffee growing areas in the world as an invasive species, with nearly 160 records from different areas worldwide on the Plantwise Distribution Map. Coffee is an extremely important commodity in many countries, including Brazil, Peru, Columbia, Vietnam, India and Indonesia. CABI is currently running a project led by Soetikno S. Sastroutomo in partnership with the Indonesian Coffee and Cacao Research Institute (ICCRI) and Papua New Guinea Coffee Industry Corporation Ltd (CIC) to address problems with the Coffee Berry Borer in Indonesia, where over 920,000 ha of coffee are infested, 95% of which are farmed by small holder farmers. Papua New Guinea is one of the last two remaining coffee nations without the pest, so the project also aims to prevent the establishment of the pest in Papua New Guinea and save the country’s extensive coffee growing areas. The CABI project is applying knowledge from Coffee Berry Borer management in African and Latin American countries to create a country-specific management program with an emphasis on Integrated Pest Management techniques and training for farmers in order to combat the Coffee Berry Borer. A recent paper published this year highlights the potential for Integrated Pest Management (IPM) programs in the management of Coffee Berry Borer, using a case study from a large coffee plantation in Colombia. Farm managers and harvest workers received training workshops on pest management strategies based on prior research and the recommendations of the National Coffee Research Center in Columbia in order to implement effective IPM strategies. Continue reading →
Soybean (Glycine max) is an important crop that provides a sustainable source of protein and oil worldwide in countries such as the USA, Brazil, Argentina, India and many African countries, including Nigeria, South Africa and Uganda. The soybean cyst nematode Heterodera glycines is a microscopic roundworm that feeds on the roots of soybean and is a major constraint to soybean production. This nematode causes more than US$1 billion in yield losses annually in the United States alone, making it the most economically important pathogen on soybean. For over 50 years the planting of resistant cultivars and crop rotation have been the main management strategy for this pathogen, and only a few resistant plant types are used due to undesirable traits in other resistant varieties of soybean. Moreover, the increase in virulent populations of the nematode on most known resistant plant sources coupled with the very limited knowledge of soybean resistance mechanism makes the development of new approaches for control of soybean cyst nematode a necessity. Continue reading →
Researchers at Swansea University have found a strain of fungi that could replace harmful pesticides in the control of the European crane fly (Tipula paludosa). The effects of 17 strains of entomopathogenic fungi, chlorpyrifos-based pesticides and a nematode worm were compared. The pesticides and fungal strain V1005 Metarhizium robertsii were both found to be 100% effective at controlling crane fly larvae, which are pests to many crop and tree species. The larvae, known as ‘leatherjackets’, feed on cereals, cabbages and lettuces, as well as young tree saplings, resulting in millions of pounds of damage every year in Europe and North America. Continue reading →