Helping plants to help themselves
2 June 2010
With the need to feed an ever increasing world population, we must reduce crop yield losses in new, sustainable ways. A paper published in the journal Food Security by Dr Toby Bruce from Rothamsted Research (an institute of BBSRC), emphasises the need to reduce crop losses caused by pests.
The Food and Agriculture Organisation, predicts that by 2050 global food production needs to increase by 70%. As an alternative to agrochemicals, natural plant defence could be induced with activators. Toby Bruce said, "Natural plant immunity is likely to become more important in the future; this is an approach which exploits natural chemicals as treatments to modulate defence responses." Signals released by damaged plants activate the defence mechanisms of neighbouring plants and make them more resistant to the impending insect attack. According to Dr Bruce, such signals could be used as alternative treatments to replace synthetic insecticides which could then be reserved for particularly bad pest infestations. Furthermore, by encouraging natural enemies of pests, plant activators are compatible with integrated pest management systems.
In 2009 the European review of pesticide approval passed a new directive (EC/91/414) which reduced the number of active ingredients authorised for use in pesticides. Scientists predict that this could ultimately reduce agricultural productivity. The new directive will necessitate finding new ways to minimise crop losses due to insect pests.
An example of this, in Africa, is a mixed cropping system known as push-pull. This system, devised at Rothamsted Research with collaborators from the International Centre of Insect Physiology and Ecology (icipe), Kenya, optimises yields and is already working effectively in over 30,000 smallholder farms. The intercrop, planted with the main crop, releases signals (semiochemicals) that repel pests out of the main crop (push) but attract the natural enemies of the pests into the crop. A trap crop is planted around the outside which attracts the pests of the main crop (pull). This method has collateral benefits as the companion plants (the intercrop) produce animal fodder and improves soil quality.
Although several different techniques show potential for reducing crop losses, there is not one simple solution. Dr Bruce emphasises that 'we cannot rely on one method alone since that would increase the likelihood of pests adapting to become resistant'. The limited number of pesticides now available increases the chance of resistance developing and more research into crop protection is urgently needed to provide effective control alternatives. There is sometimes a 10-20 year lag time between initial experiments and commercial use, partly due to stringent regulatory requirements.
Development of resistant crops could provide a good way forward. If the genes responsible for resistance to pests could be identified, they could be bred into specially selected crops by either conventional or GM methods. GM crops that are resistant to pests have already been proven to be an important tool in developing sustainable alternatives to chemical pesticides. GM is not the only option we have available for crop protection, but given the challenges we face in securing future food supplies all technologies need to be considered, keeping possible social, economic and policy implications in mind.
Notes to editors
This research is published in the current issue of Food Security (Food Security: Volume 2 (2) (2010):133, http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s12571-010-0061-8.) as "Responding to the threat to food security caused by crop pests in the new millennium" by Toby J. A. Bruce. Rothamsted Research receives grant-aided support from the Biotechnology and Biological Sciences Research Council (BBSRC) of the UK.
About Rothamsted Research
Rothamsted Research is based in Hertfordshire and is one of the largest agricultural research institutes in the country. The mission of Rothamsted Research is to be recognised internationally as a primary source of first-class scientific research and new knowledge that addresses stakeholder requirements for innovative policies, products and practices to enhance the economic, environmental and societal value of agricultural land. The Applied Crop Science department is based at Broom's Barn, Higham, Bury St. Edmunds. North Wyke Research is located near Okehampton in Devon. Rothamsted Research is an institute of the Biotechnology and Biological Sciences Research Council.
icipe is a tropical organisation established in Kenya in 1970 to research tropical insects and their impact on food security and health. icipe's mission is to help alleviate poverty, ensure food security and improve the overall health status of peoples of the tropics by developing and extending management tools and strategies for harmful and useful arthropods, while preserving the natural resource base through research and capacity building. See www.icipe.org
BBSRC is the UK funding agency for research in the life sciences. Sponsored by Government, BBSRC annually invests around £470M in a wide range of research that makes a significant contribution to the quality of life in the UK and beyond and supports a number of important industrial stakeholders, including the agriculture, food, chemical, healthcare and pharmaceutical sectors.
BBSRC provides institute strategic research grants to the following:
- The Babraham Institute
- Institute for Animal Health
- Institute of Biological, Environmental and Rural Sciences (Aberystwyth University)
- Institute of Food Research
- John Innes Centre
- The Genome Analysis Centre
- The Roslin Institute (University of Edinburgh)
- Rothamsted Research
The Institutes conduct long-term, mission-oriented research using specialist facilities. They have strong interactions with industry, Government departments and other end-users of their research.