Entomotoxic effect of Aerosil 200 Nano Particles against three main stored grain insects

Laboratory experiment was conducted to evaluate the toxicity of fumed silica, Aerosil 200 nano particles (99.8% Sio2) against three main stored grain insects which are cosmopolitan and serious pests of cereals and legumes. These insects are, rice weevil, Sitophilus oryzae, lesser grain borer, Rhyzopertha dominica and cowpea beetle, Callosobruchus maculatus at 28±2 ° c and 65±5 % R.H. Results showed that, at the highest conc., 1gm/kg for C.maculatus, 1.5 gm//kg for R.dominica and 2.5gm/kg for S.oryzae, complete mortality (100%) was observed on 2nd, 3rd & 6th day from treatment with C. maculatus, R. dominica and S. oryzae, respectively. Complete reduction in F1-progeny was recorded at all concentrations with C.maculatus and with R.dominica except the lowest conc. while, reduction in F1-progeny with S. oryzae ranged from (67-100%). Characterization of nano particles by transmission Electron Microscope (TEM) indicates that the original morphology of particles approximately spherical with the diameter varying between 5 to 20 nm.