Efficacy of Anacardium occidentale and Cymbopogon citratus as Biopesticides against Maize Weevils (Sitophilus zeamais Motsch.) on Stored Maize

An experiment on the insecticidal potency of Anacardium occidentale and Cymbopogon citratus against maize weevils (Sitophilus zeamais Motsch.) on stored maize was evaluated at 1.0g, 1.5g and 2.0g doses per 20g maize grain in 300ml rearing jars. Toxicity in terms of mortality, oviposition, F1 generation emergence, grain damage, and grain weight loss were all noted. Data collected was subjected to Analysis of Variance (ANOVA) using SPSS version 16.0 at 5% level of significance (P>0.05). When compared with the control (untreated maize), significant difference (P>0.05) in the potency of the biopesticides was observed in the parameters measured. A. occidentale performed significantly lower than C. citratus as it recorded higher (18.75±9.68) grain damage at 1.0g dose, as well as grain weight loss (0.58) at 1.0g and 1.5g treatment doses respectively. This suggests that although the plant products were tested to possess insecticidal potency against the maize weevils, C. citratus performed significantly (P>0.05) better than A. occidentale in the control of S. zeamais on stored maize. Hence, it could be used sustainably in the control of insect pests on stored products.