EFFECTS OF AZADIRACHTIN ON CUTICULAR PROTEINS OF SPODOPTERA LITURA (LEPIDOPTERA: NOCTUIDAE) VIS-A-VIS THE MODES OF APPLICATION.

Abstract

Azadirachtin is a known botanical insecticide with multiple modes of action. Whether these effects have any relation with the modes of application, specifically during ecdysis process, has been the objective of the present study and accordingly the impairment, if any, among cuticular proteins of Spodoptera litura (Fab.) was determined. Azadirachtin was applied topically, via injection or oral administration. Azadirachtin administered via injection and topical applications severely impaired the ecdysis by 86.67 and 80.0%, respectively. However, this impairment via oral administration was significantly lower (73.33%). Using SDS-PAGE, the cuticular proteins were determined for treated insects under all the three modes of application. In all cases 6 protein bands (MW 9-34 kDa) were identified using markers as standard. In all treatments 3 induced proteins (MW. ~16, 20 and 23 kDa) and 1 reduced protein (~19 kDa) were observed. In case of the topical treatment a different induced protein of ~18 kDa was identified. The change in cuticular proteins, their possible role in ecdysis impairment vis-a-vis the mode of application of azadirachtin is being correlated. This will help in understanding the mode-of-action at cuticular level and also will allow developing a suitable application strategy under field conditions in insect pest management.