Toxicological Effects of Silver and Zinc Oxide Nanoparticles on the Biological and Life Table Parameters of Helicoverpa armigera (Noctuidae: Lepidoptera)

Abstract

American bollworm Helicoverpa armigera (Hubner) is a notorious pest of different agronomical and horticultural crops. Different synthetic insecticides are recommended to control H. armigera but widespread and repeated use has led to pesticide resistance in this pest. It is, therefore, necessary to develop a novel strategy to manage the population of H. armigera. Nanotechnology is the most effective and eco-friendly approach to mitigate this problem. In the present study, the bioefficacy of green synthesized nanoparticles and two different silver and zinc oxide nanoparticles with different concentrations, viz. 100, 125, 150, 175 and 200 ppm were used against the larvae. UV-vis spectrophotometer, SEM and EDX were used for nanoparticle characterization. Data were recorded daily. The result showed that in silver nanoparticles maximum larval mortality was 97%, while in zinc oxide nanoparticles, 82% was recorded against the 3rd, 4th and 5th instar of H. armigera. The effect of nanoparticles on demographic parameters was also evaluated, which increases the net reproductive rates, mean generation time and intrinsic rate in the control group compared to the treated population. After bioassay, larval and pupal duration was prolonged in the treated population compared to the control. The longevity of males, females and fecundity was also reduced. This technique will be a valuable tool in integrated pest management regimens.