Laboratory evaluation of freshly prepared juice from garlic (<i>Allium sativum</i> L.) Liliaceae as protectants against the maize weevil, <i>Sitophilus zeamais</i> (Motsch.) [Coleoptera: Curculionidae]

Abstract

Fresh prepared garlic (Allium sativum L.) juice, containing the antimicrobial allicin, was evaluated as a possible grain protectant against the maize weevil, Sitophilus zeamais (Motsch.). Each experiment was set out in completely randomized design (CRD) with four replications and a control treatment. Adult mortality and percentage weight loss were investigated. There was an observed increase in adult mortality following days of exposure in all treatments. Statistically significant (P<0.05) reduced grain loss was also observed in all the treatments when compared with the control. The juice prepared from an indigenous Nigerian garlic cultivar (GUN) was more lethal (causing 93% adult mortality), when applied topically on the freshly emerged S. zeamais adults, compared to the juice prepared from a clove of garlic purchased at a supermarket in Germany (GAG). High performance liquid chromatography (HPLC) analysis indicated that the amount of allicin in GUN was 1883.2 μg/ml while that in GAG was 3500.93 μg/ml. This study highlights the potential of A. sativum containing allicin for biorational control of maize grains against S. zeamais infestation and damage.

Keywords: Allicin, Allium sativum, biopesticide, biorational control, crop protectant, Sitophilus zeamais, stored product

African Journal of Biotechnology, Vol. 13(10), pp. 1123-1130, 5 March, 2014