Biopesticidal Potentials of some Essential Oils on Cowpea Weevil, Callosobruchus maculatus (L.) Fecundity on stored cowpea (Vigna unguiculata L Walp) in Sudan Savanna, Nigeria

Abstract

An experiment was carried out to determine oviposition deterrence effect and determine bioactive compounds in some Essential Oils (EOs) on cowpea weevil (Callosobruchus maculate L.) on stored cowpea (Vigna unguiculata L Walp). The research was conducted in the Biology Laboratory, Department of Biological Sciences, Federal University Dustin-Ma between March to May 2025.Three EOs obtained from balanite, black seed, and neem; a synthetic insecticide and a control alongside three local cowpea cultivars (Dan Misra, Kwankwasiya, and Kananado). Data were measured on adult mortality, oviposition and progeny emergence. Pesticidal bioactive constituents were also determined. Data were subjected to analysis of variance (ANOVA) and significant means were separated using Duncan’s Multiple Range Test (DMRT) at 5% probability. Adult mortality was significantly (P<0.05) recorded in insecticide treated cowpeas 24 hours after infestation which was followed by balanites oil. Black seed and neem oils were statistically at par but were significantly effective than the control. Complete oviposition deterrence was recorded in insecticide treated cowpea but was not significantly (P>0.05) different with EOs. Balanite oil however recorded the least number of eggs among the EOs. Significantly (P<0.05) lower progeny emergence was obtained in EOs, but was however at par with insecticide treated and was significantly (P<0.05) different with the control. Bioactive compounds with insecticidal and repellant properties were identified using Gas Chromatography Mass Spectrometry (GC-MS) method. Tetradecane, oleic acid, Octadecanoic acid, Tetradecanoic acid 2,4-Di-tert-butylphenol, Tetradecanoic acid in black seed and Balanites oils respectively. According to these results, essential oils, especially balanite and black seed oils, can be used as environmentally benign substitutes for synthetic pesticides in the control of bruchids and sustainable cowpea storage in the study area.

Keywords: Essential oils, Callosobruchus maculatus, oviposition, deterrence, Sudan savanna