Evaluation of Different Particle Sizes and Rates of Application of Xylopia Aethiopica (Dunal) A. Rich Fruit Powder Against Callosobruchus Maculatus (F.) (Coleoptera: Chrysomelidae) On Stored Cowpea

Abstract

Particle sizes have been known to enhance insecticidal action of botanical powders. This study investigates the manipulation of different particle sizes and rates of application of Xylopia aethiopica (Dunal) A. Rich fruit powder for the control of Callosobruchus maculatus(F.).  Powder of different particle sizes (75 µm, 150 µm, 300 µm and 425 µm) was made from dried fruits of X. aethiopica. They were evaluated at five rates of application (0.2, 0.4, 0.6, 0.8 and 1.0 g/20 g of seeds) against C. maculatus under ambient laboratory conditions of (28 ± 3^oC and 70 ± 5% relative humidity). Adult mortality, number of eggs laid, adult emergence and seed weight loss were the parameters assessed. The experiment was carried out using a completely Randomized Design.  Results showed that the powder of X. aethiopica at different application rates in each of the particle sizes did not significantly (p>0.05) influence mortality of C. maculatus. Mean number of eggs laid, adult emergence and percentage seed weight loss decreased with an increase in application rates and decreased in size of the particle of X. aethiopica powder, with 75 µm particle size significantly (p<0.05) reduced oviposition and adult emergence in all rates of application compared with the control. In addition, X. aethiopica powder with 75 µm particle size was more potent than powder of particle size 150 µm, 300 µm and 425 µm.