Insecticide bioassay

The insect pests like Helicoverpa armigera Hubner, Spilarctia oblique (walker), Raphidopalpa foveicollis (Lucas), Chauliops choprai and Lipaphis erysimi Kaltenbach cause severe yield losses to hill crops in the Indian Himalayas. Considering the pest severity, a total of 23 insecticides (conventional and novel groups, botanicals and microbials) were screened. The insecticides belonging to diamide, spinosyn and avermectin group were highly toxic against lepidopteran pests. Emamectin benzoate and Flubendiamide recorded lowest LC50 value of 97.49 and 22.8 ppm against the 3rd instars of H. armigera and S. obliqua respectively. Moreover, for management of sucking pests, insecticides belonging to thiourease, neonicotinoid and Pyiridine azomethine group were found to be effective with Difenthiuron recording lowest LC50 value of 20.61 and 0.703 ppm against C. choprai and L. erysimi respectively. For management of R. foveicollis, two insecticides belonging to synthetic pyrethroid group Deltamethrin and Lamdacyhalothrin were found effective with LC50 value 12.97 and 21.33 ppm respectively. However, the botanicals and microbial insecticides did not show promising results as their median lethal values were much higher than other green label insecticides.