Efficacy of Ampligo and Cyperfos against Fall Army Worm Spodoptera frugiperda (J E Smith) Larvae

Abstract

A laboratory study was conducted to determine the efficacy of Ampligo and Cyperfos insecticides at three concentrations each against fall army worm Spodoptera frugiperda (JE Smith) larvae on maize. Using three concentrations of Ampligo: 0.13, 0.23 and 0.3 ml/ l water and Cyperfos 0.5, 1.0 and 1.5 ml/ l water bioassays were conducted with third instar larvae at 30°C± 5°C. Each treatment was replicated three times. The toxic effect was evaluated at 24, 48 and 72 hr following insecticides application. The results showed that both insecticides caused over 50% mortality; Ampligo caused 100% mortality at both recommended and higher concentrations in 48 hr similar to the higher concentration of Cyperfos. At 72 hr, 100% mortality was achieved by both Ampligo (lower concentration) and Cyperfos (recommended concentration); while Cyperfos lower concentration achieved 88.9% mortality. Ampligo outperformed Cyperfos in terms of overall effectiveness with time. This study found that Ampligo and Cyperfos can be used to effectively control S. frugiperda in Botswana.