n-hexane fraction of Zingiber officinale and Moringa oleifera interferes with biological parameters of Callosobruchus chinensis (L.) (Coleoptera: Bruchidae)

The development of insecticide resistance, high cost, misuse, dearth of technical expertise, and restrictive legislation associated with synthetic insecticides have necessitated the development of alternatives. Lessons from plant-insect interactions demonstrate that plant terpenes are worthy probes for insecticidal exploration. Hence, this study screened n-hexane fractions of Zingiber officinale and Moringa oleifera oils as protectant against Callosobruchus chinensis and revealed their chemical profiles using Gas Chromatography Mass Spectrometry (GC-MS). M. oleifera (LC50; 0.007 microlitre) was found to be more toxic than Z. officinale oil (LC50; 0.055 microlitre) to C. chinensis. The oils showed a positive correlation with concentration at 24h (r = 0.959), 48h (r = 0.977), 72h (r = 0.915) and 96h (r = 0.924). GC-MS revealed 21 and 15 volatile compounds in Z. officinale and M. oleifera oils, respectively. The most dominant were 5-(1, 5-dimethyl-4-hexenyl)-2-methyl-1,3-Cyclohexadiene (13.64%) and 8-Octadecenoic acid, methyl ester (34.52%) in Z. officinale and M. oleifera oils, respectively. The plant fractions reduced the oviposition potential, egg hatching rate, and adult emergence of C. chinensis. Taken together, the results demonstrate possible developmental and inhibitory effects of the oils against C. chinensis and points to its possible inclusion in Integrated Pest Management (IPM) practices for C. chinensis.