Evaluation of Cymbopogon flexuosus and Alpinia zerumbet essential oils as biopesticides against Callosobruchus maculatus.

This study aimed to investigate the effects of the essential oils of Cymbopogon flexuosus and Alpinia zerumbet in the treatment of cowpea [Vigna unguiculata (L.) Walp.] grains under storage conditions for the management of Callosobruchus maculatus. Measurements of the effects of these essential oils were based on contact, fumigation, and repellency tests. The lethal concentrations (LC50) obtained from the contact tests were 0.65 and 11.23 µL/20 g for the essential oils of C. flexuosus and A. zerumbet, respectively. The impact on F1 offspring increased with increasing concentrations of essential oils. The LC50 values obtained from the fumigation tests were 2.34 and 8.69 µL/L of air for the C. flexuosus and A. zerumbet, respectively. Regarding repellency, both essential oils were classified as neutral. C. flexuosus was more toxic than A. zerumbet in the contact test; however, there was no difference in their toxicities found in the fumigation test. The essential oils of C. flexuosus and A. zerumbet presented a great insecticidal potential against C. maculatus, therefore, can be an environmentally sustainable alternative to synthetic chemical fumigants. [ABSTRACT FROM AUTHOR]