Comparative efficacy of insecticides and Beauveria bassiana in management of Helicoverpa armigera (Hiibner)

摘要

Among chemical insecticides, spinosad 45% ES @ 0.40%, dichlorvos 76 EC @ 0.60% and imidacloprid 200 SL @ 4ml/litre concentration were found to be most effictive. Plots with these chemicals had fruit damage percentage viz. 0.53%, 1.00% and 1.04%, respectively. Spinosad 45% ES @ 0.40% was most efficacious. However, the efficacy of dichlorvos and imidacloprid were non-significant with each other. The treatments with biopesticides viz. Beauveria bassiana @ 4.16 g / lit were also effective resulting 1.5%fruit damage percentage compared with control plot (3.8%). Population of Helicoverpa armigera increased and reached its peak level of 3.8% / plant during 3rd week of March (standard week 11*). The highest fruit yield of 367.3 q/ha was registered in spinosad followed by B. bassiana 328.7 q/ha and low as 203.0 q/ha was recorded in untreated control. The best cost benefit ratio was obtained with spinosad 45% ES @ 0.04% (1:11.19) followed by B. bassiana (1; 10.83), chlorpyriphos 20 EC @ 0.04 % (1:9.60), dichlorvos 76 EC (1:9.52), imidacloprid 200 SL @ 4ml/litre (1:7.38), cypermethrin 25 EC (1:7.08) and monocrotophos 36 SL @ 0.04% (1:6.91).