INSECTICIDAL EFFICACY OF <i>Balanite aegyptiaca</i> (L.) SEED OIL IN THE MANAGEMENT OF <i>Callosobruchus maculatus</i> (F.) (COLEOPTERA: BRUCHIDAE) ON FRESHLY INFESTED COWPEA GRAINS

Abstract

Protection of grains against infestation and damage by diverse storage insect pests is an age-long practice that ensures agricultural produce and guarantees food security. This paper reports the insecticidal efficacy of Balanite aegyptiaca (L.) seed oil in reducing and/or inhibiting damage and loss in cowpea grains infested with freshly laid eggs. The experiment involved weighing ten grams (10 g) of cowpea grains from four different varieties into a 200 ml bottle in four replicates for both untreated and four levels of Balanite aegyptiaca treatments (0, 0.2, 0.4, 0.6 ml). The number of grains from each replicate was counted and recorded. Three pairs of 0-48 hrs old male and female C. maculatus were used to infest the grains of each replicate for both untreated and the four treatment levels. After seven days, the bruchids were removed and the number of eggs laid was counted. The four levels of B. aegyptiaca treatments were then applied to the eggs laid on the cowpea grains. The number of adults that emerged from the grains in each replicate was counted daily throughout the first filial generation (F1). All data were subjected to analysis of variance at a 5% level of probability, and significantly different means were determined using the least significant difference. The results indicated statistical significance (P<0.05) between treated and untreated grains of each variety. This demonstrated the bio-efficacy of BSO in salvaging freshly infested grains by C. maculatus. Success was mainly due to the oil’s larvicidal/suppressive or inhibitory effect on early larval instars, thereby reducing and/or inhibiting the damaging effect of C. maculatus.