Characterization of Azadirachta indica synthesized silver nanoparticles and its toxicity against Dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera:Lygaeidae)

Dusky cotton bug Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae) is a serious polyphagous pest of cotton including other crops. To consider the necessities of growing world population, the use of pesticides have been increased which have resulted insect resistance besides several side effects. Dusky cotton bug (DCB) like other pests also showed resistance to most of the pesticides. To overcome the adverse effects of pesticides, scientists have diverted their attention to develop an ecofriendly approach to combat harmful pest. Nanotechnology is considered as an alternative and an innovative technique for pest control strategy. In the current study characterizations of Azadirachta indica based green synthesized silver nanoparticles (AiAgNPs) have been carried out to investigate the toxicity against 4th, 5th nymphal instars and adult DCB. The AiAgNPs were synthesized by standard protocol and characterized by using various techniques like UV-Vis spectrum, Dynamic light scattering (DLS), Zeta potential, Fourier Transform Infra Red (FTIR) spectrometer, Scanning as well as Transmission Electron Microscopy which confirmed the AiAgNPs biosynthesis. Tukey’s HSD test revealed that AiAgNPs nanoformulation at 1250 ppm showed maximum mortality against DCB 4th instar (38.42, 69.21 and 91.95%) followed by 5th instar (34.14, 60.98 and 84.40%) and adult (27.76, 53.88 and 83.15%) post exposure period of (24,48 and 72 h) respectively for each DCB stage as compared to other concentrations used. Probit analysis showed LC 50 of tested AiAgNPs 376.04, 485.60 and 560.23 for the 4th, 5th nymphal instars and adult DCB respectively after 72 h post exposure which was positively correlated with older one. The biogenic AiAgNPs proved to be most effective compound and can be used successfully ecofriendly way in IPM program for the management of dusky cotton bug.