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Delivery of Semiochemicals within Plant-Pest-Natural Enemy Systems - PS2105

The main objective of this project is to develop the most appropriate methods for delivering semiochemicals to the crop environment to achieve the intended effect on target plant-pest-natural enemy systems and to test for potential effects on non-targets. By influencing the colonisation of crop plants and subsequent pest population dynamics, semiochemicals can thereby be used to disrupt or direct pests away from the crop and attract them to areas where they can be controlled (the “push-pull” strategy). Semiochemicals act through behavioural mechanisms rather than by toxicity and thus offer benign means of crop protection with which to minimise, supplement, or in the long-term replace, use of broad-spectrum pesticides in Integrated Pest Management (IPM). To demonstrate effective manipulation of plant-pest-natural enemy systems, semiochemicals arising from the previous Defra programme (and in future PS2101), successful representative complexes (cereal aphids, oilseed rape beetles, pea and bean weevil and comparable aphids and dipterous stemborers or midges) will be used.
In order to quantify the effects of semiochemicals and related plant stress chemicals, when deployed at more environmentally realistic and biologically complex spatial scales, research will be conducted in a tiered structure starting with laboratory and extended laboratory experiments (eg field simulator cages). Then, semi-field trials will be conducted in large field cages and polytunnel arenas which allow experiments to be done under more realistic field conditions while still retaining the ability to control and manipulate biological factors within the test systems. Finally, the most promising semiochemical systems will be tested under yet more realistic conditions in small plot field trials.
The research is intended to ensure that the behavioural and biological effects of semiochemicals recorded during highly controlled laboratory bioassays, using equipment such as olfactometers and wind tunnels, still pertain under more realistic and complex conditions and at greater spatial scales. This is essential before strategies for deploying the semiochemicals within integrated pest management systems are tested in expensive larger scale field trials in Project PS2107, which requires the development of rather different approaches to the testing techniques for conventional pesticides.
The research will contribute to Defra’s policy objectives of minimising the use of conventional pesticides and promoting sustainable, adaptable and cost-effective arable and horticultural crop production methods which meet consumer requirements for a safe food supply chain and environmentally-responsible growing systems.

1. Identify optimal delivery systems for plant activators (typified by cis-jasmone) and assess impact on representative crop/pest scenarios (initially cereal aphids, extending to oilseed rape and legume systems)2. Determine methods for exploitation of host plant recognition and avoidance cues by pests in novel crop protection strategies3. Evaluate the potential of rhizosphere allelopathy in pest control approaches4. Investigate the effects of semiochemicals from objectives 1-3 on tritrophic interactions and non-target organisms
Project Documents
• Final Report : Delivery of Semiochemicals within Plant-Pest-Natural Enemy Systems   (481k)
Time-Scale and Cost
From: 2003

To: 2006

Cost: £1,076,250
Contractor / Funded Organisations
Rothamsted Research (BBSRC)
Arable Farming              
Crop Pests              
Fields of Study
Pesticide Safety