New strategy required for delaying insect resistance to Bt crops

Kenyan farmer Mary Ngare in her maize field damaged by stem borers © CIMMYT (CC BY-NC-SA)

Kenyan farmer Mary Ngare in her maize field damaged by stem borers © CIMMYT (CC BY-NC-SA)

Transgenic Bt crops have been grown around the world since the 1990s and have contributed to increased yields by controlling agricultural pests. Due to the importance of this technology, there has been continuous study into the development of resistance to Bt crops and how best to avoid this happening. A recent investigation into the rapid spread of Bt resistance in South Africa has revealed one of the more surprising discoveries to date, that the maize stalk borer (Busseola fusca) has evolved Bt maize resistance inherited as a dominant trait for the first time. This has significant impacts on the management of Bt crops, as current methods for sustaining susceptibility rely on the recessive inheritance of Bt resistance.

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Slicing Into The Bread Wheat Genome

Bread wheat (Triticum aestivum) is a globally important crop that accounts for 20% of the calories consumed by the world’s human population. Major work is underway to increase wheat production by expanding knowledge of the wheat genome and analysing key traits, however due to the large size and great complexity of the bread wheat genome progress has been slow. Now scientists from a number of organisations including the Centre for Genome Research at the University of Liverpool, the University of Bristol, University of California and the US Department of Agriculture’s Agricultural Research service have been working to sequence the genome and identify several classes of genes involved in crop productivity. The analysis provides a resource for improving this major crop by identifying variation in useful traits such as yield and nutrient content, thereby contributing to sustainable increases in wheat production.

Wheat (Triticum aestivum), one of the world's most important food crops © David Monniaux via Wikimedia Commons (License CC-BY-SA 3.0)

Wheat (Triticum aestivum), one of the world’s most important food crops © David Monniaux via Wikimedia Commons (License CC-BY-SA 3.0)

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Coffee Production in Hot Water- The Impacts of Climate Change on the Future of Coffee Crops

Roasted Arabica coffee beans. Arabica coffee is highly prized as having the best flavour and quality of all coffee varieties, but the future of Arabica coffee is threatened by the impacts of climate change © Sage Ross, via Wikimedia Commons (License CC-BY-SA 3.0, 2.5, 2.0, 1.0)

Coffee (Coffea) is the one of the world’s favourite drinks and the second most traded commodity after oil, accounting for annual retail value of US$ 90 billion. The two main species used in the production of coffee are Arabica coffee (Coffea arabica), which accounts for 70% of coffee production, and Robusta coffee (Coffea canephora). The productivity of Arabica and the distribution of many coffee pests and diseases are strongly linked to climate and seasonality. A series of recent studies have forecast the predicted effects of climate change on both the present and future distribution of Arabica coffee and the effects of climate change on the distribution and lifecycle of the world’s worst coffee pest, the Coffee Berry Borer (Hypothenemus hampei).

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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

Colorado Potato Beetles Left With A Sour Taste As Clover Is Found To Be As Effective As Pesticides

An adult Colorado Potato Beetle (License CC-BY-NC 2.0. via Flickr)

Eggplant or aubergine (Solanum melongena) is a crop often attacked by the Colorado Potato Beetle (Leptinotarsa decemlineata), a major insect pest of  plants from the Solanaceae family including potato, tomato and eggplant throughout North America, Europe and Asia. This insect pest is exceptionally destructive to crops and readily develops resistance to a wide variety of chemical insecticides, making research into alternative control methods vital. Now new research has revealed that the use of clover cover crops in agricultural fields of eggplants may provide an economically and ecologically viable method of Colorado Potato Beetle management that is as effective as chemical insecticides in regulating the beetle populations.

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Plant Pest Interactions: How Soybean Aphids Trick Soybean Plant Defences

An Adult Soybean Aphid © Ho Jung Yoo, Purdue University (via Wikimedia Commons)

Following on from a previous blog on the interactions between soybean plants and soybean pests,  new research on soybean (Glycine max) responses to the soybean aphid (Aphis glycines) published in Molecular Plant-Microbe Interactions has revealed some of the complex and fascinating interactions between pests and their plant hosts.  This recent research led by Dr Gustavo Macintosh and Matthew Studham from Iowa State University has shown that soybean aphids can suppress the natural plant defense response of soybean plants to the aphids through the activation of what is known as an antagonistic decoy response. For example, the aphid will induce a plant defense that is not particularly effective against the pest (the ‘decoy’ defense) while suppressing the effective defense in order for it to continue feeding on the plant.  It has further been found that aphids can actively suppress the effective defence responses of the plant while at the same time ‘hijacking’ the plant metabolism to improve the nutritional value of the plant for their own benefit. Soybean aphids do this by inducing asparagine synthase transcripts which improve the nutritional content of the phloem sap from which they feed. 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

Plantwise plant clinics – Pest diagnosis for a farmer in Barbados

A farmer, Pedro Welch, attended the Plantwise plant clinic at this year’s Agrofest 2012, the annual agricultural show in Barbados. He described the problems he was having on his lime tree, and the plant doctor diagnosed the problem straight away, giving advice on how to manage the pest. Watch the video below to see a plant clinic in action.

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Coffee Berry Borer thriving due to Climate Change

A newly published paper has found that temperature increases are benefiting coffee berry borers in East Africa. The insects are causing more damage to coffee crops and it has also been reported that their distribution range has also expanded. The researchers behind the study also predict that the damage caused by the borers will worsen in the future.

Adult Coffee Berry Borer. Georg Goergen/IITA Insect Museum, Cotonou, Benin

The coffee industry is worth $90 billion dollars and involves around 25million coffee farmers across the tropics. It is an important crop for many farmers in developing countries and all efforts need to be taken to reduce pest damage.

The coffee berry borer, Hypothenemus hampei, is the most important pest of coffee worldwide. The Plantwise distribution map shows over 150 areas in which it has been reported. Read more of this post

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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