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Insect Repellent Wheat Trials Underway

30 March 2012

UK - Scientists from Rothamsted Research are conducting a controlled experiment, combining modern genetic engineering with their knowledge of natural plant defences to test whether wheat that can repel aphid attacks works in the field.

Aphids (also known as greenfly and blackfly) are unwelcome visitors that suck sap from plants. They cause significant damage to agriculture and reduce farmers' yields by damaging crops and spreading plant diseases.

Wheat is the most important UK crop with an annual value of about £1.2 billion. Currently a large proportion of UK wheat is treated with broad spectrum chemical insecticides to control cereal aphids that reduce yields by sucking sap from plants and by transmitting barley yellow dwarf virus. Unfortunately, repeated use of insecticides often leads to resistant aphids and kills other non-target insect species including the natural enemies of aphids, which could have a further impact on biodiversity.

Scientists at Rothamsted, funded by the UK Government through the Biotechnology and Biological Sciences Research Council (BBSRC) have been seeking novel ecological solutions to overcome this problem in wheat.

One approach has been to use an odour, or alarm pheromone, which aphids produce to alert one another to danger. This odour, (E)-?-farnesene, is also produced by some plants as a natural defence mechanism and not only repels aphids but also attracts the natural enemies of aphids, e.g. ladybirds.

Scientists are using biotechnological tools to genetically engineer a wheat plant which produces high levels of this aphid repelling odour, which could help promote sustainable and environmentally friendly agriculture.

This work is sponsored by the UK BBSRC and not a commercial organisation, nor for commercial gain. It forms part of a wider scientific strategy for Rothamsted Research to meet the challenge of increasing food and energy production in a more environmentally sustainable way.

The work is the product of years of studying how insects naturally interact with one another and with the plants that surround them in the ecosystem through their natural chemistry.

The decision to use genetic modification as a tool was after trying other approaches (synthetic dispensers and essential oils with high levels of (E)-?-farnesene) that did not provide effective delivery of the repellent odour.

Release of the repellent from the plant will improve the performance of the repellent as done by the wild potato. Our innovative approach to crop protection is based on an understanding of insect chemical ecology.

Use of insect repellents and attractants delivered by crops has been used successfully in a push-pull companion cropping system in E. Africa which is a non-GM system. Our new GM project will test if it is possible to deliver semiochemicals from crops themselves instead of having to grow additional companion crops.

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