Integrated effect of insecticide and sex pheromone on the tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae)

The tomato leafminer, Tuta absoluta (Meyrick), is currently a major threat to tomato globally. Growers in Ethiopia rely on insecticides to control the pest, which is not sustainable because of the insect's ability to develop resistance fast. The rational use of pesticides is useful to delay pesticide resistance. The integrated effect of sex pheromone and insecticide in the population of the tomato leafminer and its damage on tomato was investigated for two seasons between 2020 and 2021 at Melkassa center of the Ethiopian Institute of Agricultural Research (EIAR). Treatments consisted of trapping using sex pheromone alone, insecticide use alone and a combination of trapping using sex pheromone and insecticide (integrated treatment) along with the untreated control. Four fields, each with three replicates of plots for each treatment were used by keeping each field wide apart to minimize the movement of adult population of the insect. Treatment effects were assessed by counting the immature stages of the insect and damage both on the leaves and tomato fruits. Treatments differed significantly for mining larvae but not for the number of eggs. Leaf damage was significantly higher in the untreated control than in the rest of the treatments. In both years, similar trends of results for the percentage of damaged fruits were observed, which was lowest in the integrated treatment followed by insecticide alone, pheromone trap alone and untreated control. Results from this study suggest the need to integrate pheromone traps with in-secticides to achieve better protection from Tuta absoluta damage on tomato.

Automated summary

The tomato leafminer, Tuta absoluta, is a global threat to tomato crops. In Ethiopia, insecticides are currently used to control the pest, but their effectiveness is limited due to the development of resistance. This study investigated the combined effect of sex pheromone and insecticide on the tomato leafminer's population and the damage it causes to tomato plants, and found that integrating pheromone traps with insecticides provided better protection against Tuta absoluta damage.