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UK - Department for Business, Energy and Industrial Strategy

Improving food safety by reducing pesticide residues: developing a pheromone alternative to insecticides for control of thrips on legumes in Kenya

Disclaimer: The data for this page has been produced from IATI data published by UK - Department for Business, Energy and Industrial Strategy. Please contact them (Show Email Address) if you have any questions about their data.

Programme Data Last Updated: 23/03/2022

IATI Identifier: GB-GOV-13-FUND--GCRF-BB_P022391_1


Cowpea is rarely eaten in the UK, but it is a major crop across Africa south of the Sahara, where it is estimated that 38 million households (194 million people) grow it and harvest a total of 6 million tonnes per year. Cowpea is mainly grown by smallholder farmers and is an important source of protein to the urban and rural poor who cannot afford meat, fish or milk products. Unfortunately, many smallholder farmers apply chemical insecticides too frequently while struggling to control pests, so that crops for domestic consumption often contain unacceptably high levels of pesticide residues. In contrast, produce for export to Europe is required to have minimal residues, so access to pesticide-free produce is not equitable. The main pest of cowpea in Kenya is the bean flower thrips, which is a very small insect that breeds fast and is resistant to many insecticides. Smallholders end up spraying the crop repeatedly with insecticides, and this misuse and overuse by smallholder farmers has negative consequences for local consumers, particularly as cowpea is a staple food. The aim of the project is to provide an alternative to insecticides for managing the bean flower thrips in cowpea and other similar crops in Kenya. This will reduce the amount of pesticide used and so improve food safety. It will also lead to higher yields, better safety for farm workers, reduced environmental impact and more sustainable agriculture. Male thrips form aggregations for mating. They do this by releasing special chemicals (pheromones) that attract males and females. We have previously identified two male-produced chemicals in the bean flower thrips and preliminary experiments show that they attract males and females. We will synthesise these chemicals and then test them in the laboratory and in crops to understand how they affect thrips behaviour. We will then exploit the pheromone in various ways to develop a control method for the bean flower thrips. The use of the pheromone will be developed to attract large numbers of thrips to sticky traps for mass trapping and to disrupt and prevent mating. Another approach we will test is the use of the pheromone to attract thrips away from the crop to areas that can be spot-sprayed with insecticide. Although this still uses insecticide, it uses far less and it is not sprayed on the crop, which avoids residues. We will also develop the use of the pheromone for a method known as ""lure and infect"" in which we will attract thrips to a device where the thrips pick up spores of a naturally occurring fungus that kills thrips. The thrips then disperse with the spores and spread them to other thrips on the crop. The research will involve researchers from Keele University and Harper Adams University in the UK, working with researchers from the International Centre of Insect Physiology and Ecology, known as icipe, in Kenya. This will build the capacity for thrips research in Kenya and provide an opportunity for student placements and exchanges between Kenya and the UK.


Crops for domestic consumption in Kenya frequently contain unacceptably high levels of pesticide residues because many smallholder farmers misuse and overuse chemical insecticides while struggling to control insect pests. The current crop management systems of many smallholder farmers need to change. Cowpea is widely grown in Kenya and the rest of sub-Saharan Africa and is a staple food that is important in subsistence farming. The bean flower thrips is a major pest of cowpea and other legumes, causing crop losses of 20-80%. It is difficult to control because it has resistance to insecticides and this leads to frequent insecticide overuse. Alternative control methods for thrips on cowpea are therefore a priority for improving food safety. The development of effective alternative control methods will reduce insecticide use and so make food safer by reducing levels of pesticide residues. Alternative methods will also increase crop yields, improve safety for farm workers and reduce environmental impact. The aim of this proposal is to develop alternative control methods for the bean flower thrips on cowpea and other legumes in Kenya, using aggregation pheromone, which can be used cheaply and safely by smallholder farmers. Our ability to do this is currently limited by gaps in our knowledge of thrips aggregation pheromones and how they work. Objective 1. To synthesise the pheromone components previously identified from adult male bean flower thrips (Megalurothrips sjostedti). Objective 2. To determine the effects of the pheromone components on the mating behaviour of the bean flower thrips. Objective 3. To test the pheromone components in the field for their effects on trap catches and aggregation, and test their efficacy for control of the bean flower thrips by (a) mass trapping, (b) mating disruption and (c) spot treatment away from the crop. Objective 4. To test the efficacy of the pheromone components in ""lure and infect"" autoinoculation devices with spores of the fungus Metarhizium anisopliae (strain ICIPE 69) for control of the bean flower thrips. Objective 1 is laboratory-based at Keele and is essential to allow progress on Objectives 2-4. Objective 2 is laboratory-based in Kenya and Objectives 3 and 4 are field-based in Kenya.

Status - Post-completion More information about Programme status
Programme Spend More information about Programme funding
Participating Organisation(s) More information about implementing organisation(s)

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