The fall armyworm, Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), is an invasive insect pest attacking maize in Pakistan. In the present study, we observed the effect of insecticides on feeding behavior, food consumption and survival of S. frugiperda. Chlorantraniliprole (125 ml/ha), Spinetoram (200 ml/ha), Emmamectin benzoate (500 ml/ha), Indoxacarb (440 ml/ha), Lambda-cyhalothrin (620 ml/ha), Flubendiamide (60 ml/ha) and Novaluron (750 ml/ha) concentrations were used to observe super-lethal, lethal, median-lethal and sub-lethal effects. Results revealed that Chlorantraniliprole showed the highest mortality (94%) followed by emamectin benzoate and flubendiamide (79%), spinetoram (77%), lambda-cyhalothrin (71%), indoxacarb (68%) and novaluron (23%). It was observed that an increase in concentrations was directly proportional to mortality, but a decrease in concentrations led to a decrease in mortality. No feeding rate or food consumed by larvae due to the highest toxicity of chlorantraniliprole but in the case of novaluron maximum food consumed by larvae due to less toxicity level. The result indicates that insecticide formulations had a significant effect on 2^nd instar larval mortality, food consumption, weight gain, development time, the weight of ingested food (WIF), relative consumption Rate (RCR), final weight gain (FWG), relative growth rate (RGR), the weight of feces, approximate digestibility (AD), ingested food to body substance (ECI), the efficiency of conversion of digested food into growth (ECD) and assimilation rate (AR). Maximum larvae survival and food consumption and weight were observed in control. In the case of super-lethal and lethal doses of all treatments, S. frugiperda larvae showed maximum mortality and less food consumption as compared to median-lethal and sub-lethal treatments.

Keywords Fall armyworm, Mortality, Insecticides, Feeding, Survival.