Oviposition deterrence, progeny reduction and weight loss by Callosobruchus maculatus (F.) in pulses treated with two nanosilica formulations

Legumes are an important source of protein for humans in the world. Leguminous food is mostly attacked in storage environments by several pests. Callosobruchus maculatus (F.) is considered as the main pest of pulses. Chemical insecticides and fumigants are the main methods to control stored product pests. By considering adverse effects of these compounds, it is needed 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, the effect of two silicon dioxide nanoparticles, Aerosil® and Nanosav was investigated on oviposition deterrence of C. maculatus in four concentrations viz. 50, 100, 200, and 300 mg.kg-1 on 5 pulse seeds of cowpea, black gram, green gram, chickpea, and lentil. Pulse seeds after treatment were exposed to one-day old male and female adults. Five days after treatment the laid eggs were counted. The second experiment was carried out to evaluate the effect of two silica nanoparticles on egg hatching and adult emergence of pulse bruchid. For this purpose, the legume seeds each with a one-day old egg were treated with the same concentrations; then the seeds were assessed for hatching eggs and emerging adults. In another experiment, the effect of these formulations was checked out on weight loss and progeny production after 3 months. Declared pulses were treated with the same concentrations and then exposed to 1-day old male and female adults. After 3 months, the percentage of weight loss and the number of produced progeny were recorded. The most oviposition deterrence was on black gram with the mean percentage of 96% in 300 mg.kg-1 of Aerosil®. The least percentage of hatched eggs and emerged adults was on lentil with the mean of 13 and 1% with 300 mg.kg-1 of Aerosil®, respectively.
The least weight loss was on lentil with the mean percentage of 10 with 300 mg.kg-1 of Nanosav. The least progeny production was induced with 300 mg.kg-1 of Nanosav on lentil with the mean number of 40 progeny. The results of this study showed that Aerosil® was more effective than Nanosav, but two silica nanoparticles had enough efficiency against infestation of C. maculatus and can be used effectively in the integrated management of C. maculatus in pulses.