A farm manager checks for Tuta absoluta on tomato crops in Kajiado County, Kenya

A farm manager checks for Tuta absoluta on tomato crops in Kajiado County, Kenya (Copyright CABI).

CABI has joined forces with world-leading biological control specialists Koppert Biological Systems to step-up a more sustainable fight against the tomato farmer’s worst enemy – the tomato leafminer, known scientifically as Tuta absoluta – which in Kenya alone causes 50-80 percent yield loss if no control method is applied.

Since 2014, Tuta absoluta has become the most serious threat to the sustainable production of tomato in Kenya with nearly 98 percent of all farmers affected. CABI research shows that even where 96.5 percent of farmers apply pesticides, only 27 percent report that the treatment has been successful.

Now, CABI is working with Koppert Biological Systems, as part of a Memorandum of Understanding signed last year to collaborate on making more sustainable biological controls available in the fight against invasive pests and weeds in less developed countries, to implement a two-pronged attack against the prolific tomato leafminer in Kenya.

By implementing an Integrated Pest Management (IPM) approach with farmers in Nairobi and Kajiado Counties – using the predatory mirid Macrolophus pygmaeus (MIRICAL) and the pheromone trap system (Tutasan + Pherodis) – it is hoped that such a strategy will result in significant reduction in pesticide use and far greater yields compared to conventional farmer practices.

A recent study by Koppert Biological Systems, for example, on the impact of using an IPM approach by large commercial growers in greenhouse tomato production demonstrated up to a 95 percent reduction in pesticide use and around a 133 percent yield benefit – though their research did not take account of open field smallholders who are the majority producers in Kenya.

Tuta absoluta can devastate tomato crops and farmers’ livelihoods (Copyright CABI).

Tuta absoluta can devastate tomato crops and farmers’ livelihoods (Copyright CABI).

Dr Ivan Rwomushana, Senior Scientist (Invasive Species Management) working on the project and who co-authored the CABI evidence note ‘Tomato leafminer (Tuta absoluta): impacts and coping strategies for Africa’, said, “Tuta absoluta is a significant pest not only for Africa, where it has spread to 41 of 54 African countries since arriving in 2008, but also to other parts of the world including the Middle East and Asia.

“The early detection, correct identification of pest and damage and the use of threshold levels is key to controlling this pest using an IPM strategy that involves the biological control options that Koppert Biological Systems have already demonstrated to be effective in greenhouse conditions. Previously, the use of the predatory mirid and the pheromone trapping have been used singly, and this project attempts to integrate the two options for better management of this pest.

“We’re looking forward to working with Koppert Biological Systems and our other partners to help tomato farmers in Nairobi and Kajiado Counties grow more and lose less to this devastating pest.”

The work, which will involve deploying the two IPM techniques in small-scale greenhouses and open fields, builds upon previous work conducted by Koppert Biological Systems and Kenyatta University to validate the use of pheromone and traps for Tuta absoluta.

The new project, funded by the Dutch Ministry of Agriculture, Nature and Food Quality (MinLNV), will also see CABI and Koppert Biological Systems working alongside Latia Agribusiness Solutions, community-based organisations in the project area and the county extension departments of Nairobi and Kajiado. In addition to the application of the biological control approaches, the partnership will also implement an education and awareness campaign using video and other materials to help farmers combat the pest, and establish the cost-benefit of using IPM methods.

Additional information

Project page

Learn more about how CABI is working with Koppert Biological Systems in Nairobi County and Kajiado County combat Tuta absoluta from the dedicated webpage.


When Kilimanjaro becomes ‘unscenic’: The Tuta absoluta menace. Read more about the project in this blog written by Ivan Rwomushana and Monica Kansiime

Farmer case study

CABI is working with a range of donors and partners to help farmers, like Geoffrey Omollo, a smallholder from Nyaraha village in Western Kenya, fight crop pests including Tuta absoluta. Read more about his story in the article Helping farmers fight tomato pests, earn better incomes and build brighter futures.’


See in this video on CABI’s YouTube channel how other farmers, including Robert Maina from the Mount Kenya region, has been impacted by Tuta absoluta.

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