Contact toxicity and feeding deterrent activity of Dennettia tripetala Bak. and Jatropha curcas L. leaf extracts against Spodoptera frugiperda J. E. Smith

Abstract

Abstract Background Maize (Zea mays L.) is an important annual cereal crop with nutritional benefits, but its production is constrained by activities of insect pests. The fall armyworm (Spodoptera frugiperda) is one of the important economic pests that limits the production of maize, causing several damages on maize fields. Synthetic insecticides are commonly used to manage fall armyworm, but they have undesirable side effects on human and the environment. This study aimed to evaluate the contact toxicity and feeding deterrent activities of ethyl acetate and methanol leaf extracts of Dennettia tripetala and Jatropha curcas against fall armyworm. Results In the contact toxicity of Dennettia tripetala and Jatropha curcas extracts, larval mortality increased with an increase in exposure time and concentrations. The extracts possessed significant contact insecticidal effects that ranged between 20.00 ± 13.94% and 100.00 ± 0.00%. Also, in the feeding deterrent activity test, extracts revealed significant differences (p 0.05) in the pupal mortality and pupal weight among the treatments. Jatropha curcas ethyl acetate and Jatropha curcas methanol extracts had high flavonoid content, and tannin and phenol content was higher in Dennettia tripetala ethyl and methanol extracts. Conclusions From this study, ethyl acetate and methanol leaf extracts (75% and 100% v/v concentrations) are effective as contact and stomach poisons against fall armyworm and suitable replacements for synthetic pesticides.

Keywords

• Fall armyworm
• Tannin
• Flavonoid
• Dennettia tripetala
• Jatropha curcas
• Leaf extracts