Herbicide Resistance Gene In Black-Grass and Rye-Grass Identified

Black-grass (Alopecurus myosuroides), a serious weed of arable fields that is widley resistant to herbicides © Bas Kers, via Flickr (CC-BY-NC-SA 2.0)

Black-grass (Alopecurus myosuroides), a serious weed of arable fields that is widley resistant to herbicides © Bas Kers, via Flickr (CC-BY-NC-SA 2.0)

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.

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Monitoring and Management of Desert Locusts in Africa

An adult Desert Locust © AtelierMonpli via Wikimedia Commons (License CC-BY-SA-3.0)

An adult Desert Locust © AtelierMonpli via Wikimedia Commons (License CC-BY-SA-3.0)

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.

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Watermelon Genome Could Hold the Key to Improved Varieties With Fewer Pest Problems

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.

Watermelons suffer large yield losses due to many pests and diseases and it is hoped that new genetic research can be used to improve varieties to make them less susceptible to pathogens ©Steve Evans via Wikimedia Commons (License CC-BY-2.0).

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Bean and Gone – Controlling the Coffee Berry Borer Using Integrated Pest Management

Coffee is one of our most popular drinks, but coffee production worldwide is threatened by the Coffee Berry Borer, a tiny beetle which affects the yield and quality of coffee beans © Frank Gruber, via Flickr (License CC-BY-NC-ND 2.0)

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. Read more of this post

The Soybean Gene: Scientists Discover the Key to Nematode Resistant Soybeans

Scanning electron micrograph of a soybean cyst nematode and egg © Ethan Hein via Flickr (License CC-BY-NC-SA 2.0)

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. Read more of this post

Fungi just as effective as pesticides at controlling crop pest

Leatherjackets are amongst the crop pests being targeted with biocontrol © Rasbak (CC BY-SA licence)

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. Read more of this post

Down the pan

How about I start this week’s blog with a question……what is the common link between the newly-constructed toilet block in Kithimu market place and Maize streak virus (MSV)?

Left: The toilet block at Kithimu market (Credit: Claire Beverley ©CABI) and Right: Maize Streak Virus (Credit: AgBioForum)

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Is citrus greening coming your way?

Mexico is the latest to succumb to the inevitable spread and establishment of huanglongbing (HLB) – the devastating disease of citrus crops. Mexican authorities in the states of Jalisco, Michoacán and Colima have warned growers that HLB – otherwise known as citrus greening – is here to stay.

HLB was first detected in Mexico in July 2009 and it’s clear now that it won’t be going away. Some estimates suggest HLB could affect 60% of Mexico’s citrus industry, an industry which provides employment for 70,000 farmers. SENASICA, the National Service for Animal and Plant Health, Food Safety and Quality, has invested over US$20 million to control the disease. An economic impact assessment report prepared this year by consultants specializing in the economics and finance of plant health programmes indicated total losses to the Mexican economy could amount to almost $7000 million.

Mexico’s not the first to report the alarming consequences of HLB infection. The disease has been known in Brazil for some years and is spreading throughout the region. Florida first reported the disease over 5 years ago and data from 2010 showed 18% of trees in Florida are infected – for more information on the disease in Florida click here. HLB was first reported in Nicaragua and Honduras in 2010 and in Costa Rica in February this year. A recent outbreak in the Dominican Republic is said to have destroyed 34,000 trees and left 5000 unemployed.
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Pest-fighting Anthocyanins

U.S. Department of Agriculture (USDA) scientists in Illinois, USA, are investigating the role of anthocyanins in pest-control. They believe that the plant pigment can adversely affect crop pests such as the corn earworm caterpillar and the cabbage looper caterpillar that feed on it.

Cabbage looper caterpillar. Copyright A. Shelton.

Anthocyanins are a plant pigment which give blackcurrants and flowers, such as petunias, their blue and purple colour. They absorb blue-green and UV light, protecting plant cells from high-light stress.

In the experiments the scientists used corn earworm caterpillars (Helicoverpa zea). H.zea damage is usually serious and costly because of the larval feeding preference for the reproductive structures and growing points which are rich in nitrogen.

The caterpillars were forced to feed on blue areas of petunia petals which contained higher levels of anthocyanins than the white areas. It was found that these individuals gained less weight than other individuals which were fed on only the white leaf areas. Further experiments found that isolated anthocyanins slowed the caterpillar’s growth rate.

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Plant Clinics boost fight against diseases and pests

“Plant clinics boost fight against diseases, pests” – this was the title of a story that appeared in the newspaper Business Daily last week. It was one of many positive articles that were written after a group of journalists were taken to visit some Plant Clinics in Kenya.

The article includes examples where the Plant Clinics have helped farmers in Kenya.

Karanja Kinyanjui, a farmer from Kikuyu District, who supplies Nairobi’s Wakulima Market says he spent Sh10,000 on pesticides prescribed by agro-vets for his potatoes and spinach to no avail. Following this, diagnosis from the plant doctors encouraged him to spray wood ash onto his crops, which, within a week wiped out the disease.

“It still pains me to imagine that the agro-vets fleeced me of my meagre earnings,” he said.

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