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Further work on semiochemical tools for use within plant pest natural enemy systems in ICM - PS2114

The overall objective of the proposed strategic research is to identify and provide semiochemicals (i.e. chemicals that control pest or natural enemy behaviour and development or act as signals to switch on defence in plants) as alternatives to conventional pesticides. 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 (e.g. 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). Chemically-based interactions between plants and other plants or micro-organisms can similarly suppress weeds or diseases. In lower input systems, including organic farming, the use of semiochemicals complements the greater exploitation of biological control agents, selective pesticides and pest-resistant cultivars.

This continuation project combines and focuses the output from projects PS2101 ‘Identification and provision of potential semiochemical tools for use in integrated crop management’ and PS2105 ‘Delivery of semiochemicals within plant-pest-natural enemy systems’. As such it amalgamates the Objectives from these two projects and condenses the key areas in four new Objectives. It will continue to investigate new semiochemicals and plant stress chemicals as alternative plant protection technology, provide all semiochemical materials and 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-target species.
The research is intended to identify new plant stress signals that can act as plant activators, and investigate the combined role of pheromones and other semiochemicals in host plant location and avoidance of unsuitable potential hosts, for pests and their natural enemies. It will also determine the potential value of exploiting rhizosphere allelopathy (interplant beneficial e.g. to crop plants or detrimental effects e.g. to weeds) to develop a broader semiochemical approach to crop protection, including suppression of diseases, weeds and pests. Plant varieties that respond optimally to pest damage, plant activators and allelopathic interactions will be exploited in breeding programmes, e.g. via LINK, to be of practical benefit in UK agriculture and to reduce significantly pesticide use
To demonstrate effective manipulation of plant-pest-natural enemy systems, representative complexes (e.g. cereal aphids, oilseed rape beetles, pea and bean weevil and comparable aphids and dipterous stem borers 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 (e.g. 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 'A framework for the practical use of semiochemicals in field crops’, which requires the development of different approaches to the testing techniques for conventional pesticides.
New strategies for exploiting insect predators and parasites, via semiochemical tools, will be taken forward through arable and horticultural LINK programmes.

The research will contribute to Defra’s policy objectives on developing alternatives to pesticides thereby 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.
This is a continuation of the Defra funded projects PS2101 and PS2105, which have been combined for year 4. For the fourth year milestones, the four Objectives of each of these projects have been combined as follows;

1. Focus on the identification of new plant stress signals to extend the practical range already obtained with cis-jasmone. These will act as plant activators for which optimal delivery systems will be devised and impact on representative crop/pest scenarios, determining effects up to the third trophic level, will be assessed.

2. Identify semiochemicals associated with host plant location and avoidance of unsuitable potential hosts by representative pest species. Determine methods for exploitation of host plant recognition and avoidance cues by pests in novel crop protection strategies.

3. Determine and evaluate the potential of exploiting rhizosphere allelopathy, in controlling pest/plant interactions, and suppressing competitive weeds.

4. Identify new strategies for exploiting insect predators and parasitoids via semiochemical tools.

Project Documents
• Final Report : Further work on semiochemical tools for use within plant pest natural enemy systems in ICM   (3010k)
Time-Scale and Cost
From: 2006

To: 2007

Cost: £486,000
Contractor / Funded Organisations
Rothamsted Research (BBSRC)
Crop Pests              
Pest and Weed Control              
Pest Control              
Pesticide use              
Plants and Animals              
Fields of Study
Pesticide Safety