Evaluation of plant powders <i>Azadiracta indica</i> and zingiber officinale against the bean weevil, <i>Callosobrucus maculates</i> (fab.) (coleoptera) in storage of bean grain

Abstract

The study was carried out to investigate the efficacy of two botanical powders Azadiracta indica (A Juss) leaves and Zingiber officinale (Roscoe) rhizome in the control of Callosobrucus maculatus (Fabricius) damage on stored beans seed (Vigna unguiculata L. Walp). The two botanicals were applied at the rate of 0, 2, 4, 6 and 8 grams respectively for the control of C. maculatus, against a standard pesticide. The botanical powders were introduced into 50 g of clean beans and thoroughly mixed together by agitating the vials manually, 20 unsexed adult C. maculatus were introduced into each vial and kept under ambient conditions (27 ± 3 0 C and 80 ± 10 RH) for a period of 96 hours in July 2016. Each set of experiment was laid out in a completely randomized design comprising six treatments with each treatment having four replicates. Results from the data analyses showed that treated bean grains in storage recorded significantly higher (p<0.05) mean mortality of adult C. maculatus than the untreated controls. Batches treated with higher doses (4, 6, 8 g) had comparatively higher and significant total mortality of adult C. maculatus than those treated with smaller dosages (0 and 2 g).

Keywords: Botanicals, Azadiracta indica, Zingiber officinale, Efficacy, Vigna unguiculata Callosobrucus maculatus