Evaluation of different management strategies to control Tuta absoluta (Lepidoptera: gelechiidae) in tomato

Tomato leaf and fruit miner (Tuta absoluta) is a destructive pest of tomato and other Solanaceae plants in the world. The pest is problematic in open field and in greenhouses and can cause 80% to 100% yield loss if not properly managed. It was first reported in Sri Lanka during July 2017 on tomato in some poly-tunnels in Badulla District and later spread to many other areas in the country. As the pest is new to the country, no recommended insecticides or control measures were available at the time of initiation of this study. Therefore, experiments were carried out in poly-tunnels and in open fields for five consecutive seasons started from 2017 Yala to identify appropriate management strategies to control the larvae, and trapping methods to monitor and control of adults. Eleven insecticides were tested in poly-tunnels and four insecticides viz., Spinetoram 25% WG (2.5 g/10 L), Emamectin benzoate 5% SG (4 g/10 L), Indoxacarb 150 g L^-1 EC (4 mL/10 L) and Abamectin 18 g L^-1 EC (6 mL/10 L) were selected for further studies based on larval mortality recorded 24 hrs after application. Simultaneously, eight different traps including light, sticky, insecticidal and pheromonal were evaluated for mass trapping of T. absoluta adults in greenhouses. Results revealed that selected chemicals were effective in managing T. absoluta larvae in greenhouse tomato whereas only Spinetoram 25% WG (2.5 g/10 L) was effective for the same in the open field. The CFL light traps were suitable for mass trapping of T. absoluta adults in greenhouses. Pheromone traps can be used to monitor adult population.