Azadirachtin influences total head protein content of Helicoverpa armigera Hub. larvae

Laboratory experiments were conducted to study the effect of azadirachtin on the head protein levels in Helicoverpa armigera larvae. Azadirachtin at 0.1 µg showed an optimum decline (30%) in protein level up to 72-h in 7-day-old H. armigera larvae. However, the magnitude of reduction (23%) in 20-day-old larvae was observed only 24-h after treatment. Twenty-old-larvae retained the mean protein concentration (22.7 mg/g) over the 72-h period compared to the corresponding control larvae (24.11 mg/g). Medium to low doses of azadirachtin significantly influenced the total head protein profile in H. armigera. Azadirachtin was effective in reducing the protein concentration at 0.1 µg by topical application in the second stadium. However, the treated larvae did not show the same protein concentration up to 72-h compared to the control. Nevertheless, azadirachtin in the sixth day stadium restored protein concentration up to 72-h compared to the control. In addition, azadirachtin did not maintain reduced level of protein for 72-h. Injection of azadirachtin in the fifth stadium in increasing doses, showed a dose-dependent trend in protein level. It also resulted in a maximum decrease in protein level at 0.5 µg.