Field persistence of certain new insecticides and their efficacy against black cutworm, Agrotis ipsilon (Hufnagel)

Abstract

BackgroundChemical control is used as a rapid and reliable method for insect control. Still, there is an ongoing need to replace older conventional insecticides with new insecticides to maintain efficacy and environmental protection. Emamectin benzoate, indoxacarb and chlorantraniliprole are broad-spectrum insecticides with a novel mode of actions. The effects of these compounds on some biological aspects of the black cutworm, Agrotis ipsilon, and their field persistence residues were estimated.ResultsThe results showed that egg hatch was affected by high concentrations (50 and 100 ppm) of the tested compounds. Larvae that hatched from treated eggs were significantly affected at concentrations of 25 ppm and higher. 1st-instar larvae were the most susceptible developmental stage. There was strong suppression of adult formation; 65 and 91% at 25 and 50 mg L−1, respectively. Profoundly affected larvae died before pupation; slightly affected ones reached pupation 2–4 days later, were smaller than larvae in the untreated control, and were sometimes unable to develop into normal adults. Comparatively high concentrations (50 and 100 mg L−1) of the test compounds were necessary to affect adults by ingestion. According to the results, the tested insecticides could be arranged according to their potency descendingly as follows: emamectin benzoate, indoxacarb, and chlorantraniliprole, respectively. Based on the field application, emamectin benzoate proved to be the most effective in initial and residual activity, causing 100% mortality while indoxacarb was least effective. Data also indicated that emamectin benzoate had the longest half-life (Lt50) while indoxacarb recorded the shortest one.ConclusionsThe results obtained in this study indicate that emamectin benzoate, indoxacarb and chlorantraniliprole are potent compounds for controlling A. ipsilon. Therefore, these compounds are promising materials that can be used as alternative components in integrated pest management programs to reduce as possible the harmful of using conventional insecticides under field conditions.