Testing Efficacy of Selected Insecticides against Spodoptera litura (Lepidoptera: Noctuidae) in Fodder Crops and Effects on Beneficial Insects

Abstract

The armyworm, Spodoptera litura Fab. (Lepidoptera: Noctuidae) is an economically important insect pest of vegetables, ornamentals and other agricultural crops. Synthetic insecticides have remained primary means for the management of S. litura than any other management tool. We tested the effectiveness of some insecticides against different larval instars of S. litura in laboratory as well as in field on the prevailing instars in two fodder crops lucern/alfalfa, Medicago sativa L. and jantar/sesbania, Sesbania sesban L. In the laboratory, emamectin benzoate provided the most control 69-91% followed by lufenuron 70-85% of all larval instars after 48 hours of application. In the lucern field, emamectin benzoate reduced the larval population of S. litura up to 79.32% and with the application of lufenuron 73.55% reduction occurred. Similarly, in jantar crop, lufenuron and emamectin benzoate proved to be more toxic against S. litura population. The abundance of ladybird beetle, Coccinella septempunctata L. (Coleoptera; ‎Coccinellidae), honeybee, Apis mellifera L. (Hymenoptera; Apidae) and green lacewing, Chrysoperla carnea Stephen (Neuroptera; Chrysopidae) were found higher in emamectin and lufenuron treated plots compared to methoxyfenozide and chlorpyrifos. These results indicate that new chemistry insecticides; emamectin benzoate and lufenuron have a potential for the management of S. litura and are relatively safer for beneficial insects as compared to conventional insecticides, methoxyfenozide, and chlorpyrifos.