Lethal and sublethal effects of different insecticides against the fall armyworm, <i>Spodoptera frugiperda</i> (Lepidoptera: Noctuidae)

The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), which has entered Egypt in the current decade, is considered one of the most destructive pests of economic agricultural crops, mainly maize. This pest is difficult to control without using chemical insecticides because of its rapid spread over fields with severe infestations. In this study, the chemical insecticides indoxacarb, hexaflumuron, profenofos, methoxyfenozide, spinosad, tolfenpyrad, and lufenuron were tested for their acute and latent activity against S. frugiperda. The insect growth regulators lufenuron, methoxyfenozide, and hexaflumuron proved to be the most toxic to S. frugiperda larvae, followed by indoxacarb and spinosad. The tested insecticides affected the biological aspects of the consequent development stages of treated larvae. Hexaflumuron and lufenuron resulted in the lowest pupation percentage. Tolfenpyrad induced the highest percentage of deformed pupae, while methoxyfenozide resulted in the least percentage of normal adults. Based on the outcomes of this study, lufenuron, methoxyfenozide, hexaflumuron, and tolfenpyrad could be effectively used to face the menace of S. frugiperda on host plants.