Lethal and sublethal effects of flubendiamide and spirotetramat against the leaf worm, Spodoptera litura (Fabricius) under laboratory conditions

The leaf worm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) is a notorious insect pest of many economically important cultivated crops like cotton, maize, tobocco and vegetables causing severe economic losses from 50-100%. In most crops, damage arises due to voracious feeding by the larvae and leads to the skeletonizing of leaves. Toxicological studies were performed to estimate lethal and sublethal levels of flubendiamide and spirotetramat against S. litura. Effects of these estimated values were assessed on different biological traits of S. litura including life duration, survival and next generation potential. Both flubendiamide and spirotetramat showed toxic responses against second instar larvae of S. litura under laboratory conditions. Larval duration and survival rate of S. litura to were significantly different. Exposure to test insecticides resulted in negative effect on the demography of S. litura as longer life cycle and decreased fecundity. Changes in net reproductive rate and intrinsic rate of increase also helped to decide the fate of these insecticides. Low reproductive potential and low hatching percentage due to exposure to test insecticides can help to manage next generation of target pest. These two new chemistry insecticides can be recommended for their effective and long-term utilization against this important leaf feeder which may help its management and decrease economic losses faced by the growers. Their impact on larval duration and low survival rate at lethal levels guides about their potential in pest control.