TOXICITY OF COMMONLY USED CHEMICAL INSECTICIDES ON MANGO HOPPER

Mango production in Bangladesh is enormously affected by the infestation of hopper which punctures and sucks sap from tender shoots, inflorescences, and leaves of mango tree, causing non-setting of fruits and dropping of immature fruits. Control of mango hopper in recent days is solely done by synthetic insecticides. This study was conducted in the laboratory during January to October 2022 to know the toxicity of four commonly used insecticides, namely Desis 2.5 EC (Deltamethrin), Ripcord 10 EC (Cypermethrin), Relothrin 10 EC (Cypermethrin), and Sumithion 50 EC (Fenitrothion) on mango hopper. The doses of Desis 2.5 EC, Ripcord 10 EC and Relothrin 10 EC were prepared as 1200, 1000, 750, 500 and 100 ppm, and Sumithion 50 EC solutions were 2500, 2200, 1500, 1000 and 500 ppm. Results showed that the tested insecticides with their recommended doses revealed 51.4±2.5 to 70.6±1.8% mortality of hopper at 4 hours after treatment where Desis 2.5 EC showed the highest mean mortality of the insect. Desis 2.5 EC also showed the lowest LC50 and LC95 values (426.0 and 4331.4 ppm, respectively at 4 hours after treatment) signifying its higher effectiveness compared to other tested insecticides.