بررسی اثر بازدارندگی دو فرمولاسیون نانو ذرات سیلیکا بر تخم‌ریزی سوسک چهار نقطه‌ای حبوبات Callosobruchus maculatus F. (Coleoptera: Bruchidae)

Legumes are important source of protein for humans in the world. Leguminous food is mostly attacked in storage environment by bruchid beetles. Callosobruchus maculatus F. (Coleoptera: Bruchidae) is considered as the main pest from bruchids. It is a field and storage insect pest, but most of the damage is done during storage. Chemical insecticides and fumigants are the main method to control stored product pests. These compounds have many serious problems such as: pest resistance, environmental hazards, health threat to users, and increasing costs. It is in the light of the above problems that the need to develop alternative control strategies that will be effective, biodegradable, cost-effective, and without any adverse effect on non-target organisms. Nano particles are the new generation of these safe products. In this study we evaluated the efficacy of two formulations of silica nano particles, Aerosil 200® and Nano Silica® on oviposition deterrence of the cowpea weevil by 5 pulse seeds of Vigna unguiculata, Vigna radiate, Vigna mungo, Cicer arietinum, Lens culinaris. Experiment carried out at 30±2°C, 55±5% R.H. and a photoperiod of 12:12 hours light: dark conditions. Five concentrations of each formulation viz. 20, 50, 100, 200, and 300 mg/kg along with a control group were applied in nine replicates. Ten grams of seeds after treatment were exposed to 3 pairs of one-day old adults. Five days after introducing the weevils, oviposited eggs in each replicate were counted. In all pulses, Aerosil 200® significantly showed higher oviposition deterrence in comparison with Nano Silica® except for lentil (P= 0.001). A direct relationship between mean percentage of oviposition deterrence and concentrations was observed at two nano particls (P= 0.001). The interaction between nanoparticles and concentrations was significant (P= 0.001). Aresil 200® with 300 mg/kg had the highest effect on black gram, chickpea, green gram, and cowpea with 91.3, 84.29, 83.33, and 76.19 mean oviposition deterrence percentage, respectively. Nano Silica® with 300 mg/kg showed the most oviposition deterrence on Lentil with mean of 96.81%. Our findings showed that Aerosil 200® exhibited strong oviposition deterrence on C. maculatus.