BIO EFFICACY OF MORINGA OLEIFERA SEED OIL AGAINST COWPEA BRUCHID (CALLOSOBRUCHUS MACULATUS) INFESTATION ON A SUSCEPTIBLE COWPEA VARIETY

Sadiya Ibrahim Karaye*, Mas’ud Abubakar, Nura Abdullahi, Muhammad Sani Tajo Tukur and Muhammad Salihu Ibrahim

ABSTRACT

Cowpea (Vigna unguiculata L Walp) is a vital legume crop in sub-Sahara Africa but suffers heavy postharvest losses due to infestation by the cowpea bruchid (Callosobruchus maculatus). In this study, the insecticidal properties of Moringa oleifera seed oil were evaluated against C. maculatus using the most susceptible cowpea variety (IT98K-573-1-1) under laboratory conditions. Moringa seeds were collected and processed to obtain oil through soxhlet extraction. The oil was applied at varying concentrations 2.5, 5.0 and 7.5%v/w, respectively to disinfect the cowpea seeds, with synthetic pesticide (Dichlovos) and untreated controls included. Bioassays revealed significant dose- dependent mortality of adult beetles, achieving 100% mortality within 72 hours at all oil concentrations. Moreover, oviposition and egg viability were substantially reduced, with complete suppression of F1 adult emergence at all treatment levels. The seed oil showed comparable efficacy to the synthetic pesticide but with the added benefit of being natural, readily available, and environmentally safer. These results indicate that M. oleifera seed oil is a potent bio pesticide candidate for managing C. maculatus in stored cowpea. Further phytochemical investigations are recommended to isolate and characterize the active constituents responsible for its insecticidal activity.

Keywords:

Moringa oleifera, cowpea bruchid, seed oil, oviposition, mortality, adult emergence and stored cowpea.

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