Comparative Efficiency of Selected Chemical and Bio Pesticides against some Stored Grain Insects

Abstract

Stored grain insect pests cause a high risk to the grains and seeds in storage such as weight loss, less germination, and reduced nutrition values of grains. Heavily use of synthetic insecticides resulted in a lot of problems for humans and the environment. Therefore, the present study aimed to evaluate new approaches for controlling certain stored product insects. In this respect, the following approaches were investigated: Acutely toxic chemicals, mostly of natural origin, i.e. Avermectins and pyrethrins against stored insect pests. In addition to Azadirachtin, the main constituent of neem kernels is a feeding deterrent. Some toxicological and environmental aspects of some tested chemicals were also evaluated. The results showed considerable and remarkable insecticidal activity. Avermectins, in particular, Ivermectin exhibited a noticeable insecticidal potency against the stored grain insects (i.e. cowpea weevil, Callosobruchus maculatus F., and khapra beetle, Trogoderma granarium E.) under storage conditions (viz. lacking direct light and other weathering factors). yrethrins revealed a long residual toxicity when applied on grains. Azadirachtin, the principal phytochemical of neem kernels, has markedly antifeedant properties. Also, Azadirachtin showed considerable feeding deterrent effect against larvae of khapra beetle, T. granarium at concentrations  125 mg/kg grains. Moreover, the results showed that Abamectin was highly effective. The present study was planned to evaluate the insecticidal potency of Abamectin, ivermectin pyrethrins, Malathion and Azadirachtin against cowpea weevil, khapra beetle adults and its larvae through some bioassay methods included contact toxicity, residual toxicity, and anti-feedant activity.