Potential for insecticide resistance on Kenyan populations of Tuta absoluta

Research poster
Denis Nyamu
Luis Canas
Department of Entomology

Tomato (Solanum lycopersicum) is one of the most important vegetable crops marketed in East Africa. In Kenya, most tomato growers are small scale farmers, practice open field cultivation and are faced with invasive pest species. Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), known as the South American tomato moth, is a major invasive pest species in Kenya threatening tomato production. Traditionally this pest has been controlled using conventional insecticides in many parts of the world where it has been introduced. Several classes of insecticides have been used in the management of this pest including organophosphates, pyrethroids, diamides and spinosyns.
In Kenya T. absoluta was introduced in 2014. Since its introductions, it has spread to all the tomato producing regions in the country. Management of this pests can best be achieved through integrated pest management (IPM). For this study we developed a survey to understand how farmers currently manage T. absoluta. We conducted the survey using tablets formatted with questionnaires using Kobo toolbox software in three major tomato producing counties. The results indicate that T. absoluta is the second most important tomato pest. Furthermore, insecticides are the major control tactic used, with diamides being the most widely used insecticide group. Most Kenyan farmers use insecticides registered for the control of this pest. Despite its huge potential IPM is still a foreign term among farmers. Future studies should focus on evaluating the efficacy of these insecticides as well as possible development of insecticide resistance.