Evaluating the impact of biogenic nanoparticles and pesticide application in controlling cotton leaf curl virus disease (CLCuD) in cotton (Gossypium hirsutum L.)

Cotton leaf curl virus disease (CLCuD) is one of the major concerns for cotton growers. The traditional approach to managing CLCuD involves the control of the vector (whitefly) population through the use of pesticides. This study compares the efficacy of zinc oxide, iron oxide, copper and silver nanoparticles with conventional pesticides. Nanoparticles dose was optimized by evaluating their phytotoxic threshold in our previous study. In this study, optimized doses of nanoparticles such as zinc oxide (100 ppm), iron oxide (50 ppm), copper (50 ppm) and silver nanoparticles (25 ppm) were applied in a field trial of cotton against cotton leaf curl virus disease (CLCuD). Morphological parameters (height of stem, monopodial branches, sympodial branches, staple length, boll weight and number of bolls), yield parameters (seed cotton yield and ginning outturn), chlorophyll content (chlorophyll a, chlorophyll b, carotenoids and total chlorophyll), biochemical parameters (superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), hydrogen peroxide (H2O2) and electrolyte leakage) and disease parameters (reduction infection, disease severity and disease incidence) were determined in this study. The incidence of cotton leaf curl virus was confirmed by triple antibody sandwich–enzyme-linked immunosorbent assay (TAS-ELISA). The pesticide Imidacloprid significantly reduced the infection by 79.3%. However, in comparison to pesticide, application of nanoparticles also reduced the infection. ZnO NPs reduced the infection by 42.33%, FeO NPs by 41%, Cu NPs by 34.7%, and Ag NPs by 44.8%. Moreover, these nanoparticles also improved the plant growth parameters as compared to control treatment. ZnO NPs enhanced morphological, yield parameters, and chlorophyll content by 36%, 22%, and 29%, respectively. FeO NPs showed improvements by 38%, 21%, and 29%; Cu NPs 39%, 25%, and 29%; and Ag NPs 31%, 19%, and 18%, respectively. Although treatment pesticide showed the least disease incidence compared to nanoparticles, nanoparticles are eco-friendly and safe as compared to pesticides. Farmers can apply these nanoparticles at their optimal thresholds through foliar application as an alternative to traditional pesticides. It is concluded that nanocomposites and hybrid modes may be used for managing CLCuD efficiently in the future.