Sequential Use of Insecticides for Pectinophora Gosssypiella Affects Bemisia Tabaci and Natural Enemies’ Population in Cotton

Whitefly (Bemisia tabaci Genn.) and Pink Bollworm (Pectinophora gossypiella Saund.) are two major challenges in cotton (Gossypium hirsutum L.). Overdue use of synthetic pesticides especially pyrethroids flare up the whitefly population in cotton. The current study emphasizes the impact of different sequential spray schedules with special reference to pyrethroids against the B. tabaci and beneficial insects’ population in cotton during 2019 and 2020. Four sequential schedules were used i.e. Sch-1: Spinetoram→Abamectin→Triazophos (SAT), Sch-2: Chlorantraniliprole→Spinetoram→Abamectin (CSA), Sch-2: Gamma Cyhalothrin→Lambda cyhalothrin→Abamectin (GLA), Sch-4: Bifenthrin→Bifenthrin→Bifenthrin (BBB). Results revealed that maximum mean population of B. tabaci was observed in BBB treated plots which were 60.77 & 51.75 per leaf during 2019 & 2020 respectively with minimum population of beneficial insects. Highest population of natural enemies and lowest B. tabaci mean population 11.48 & 18.22 per leaf was observed in CSA treated plots followed by SAT treated plots. PBW infestation percentage was found highest in untreated plots followed by BBB and minimum infestation found in treatment CSA and SAT respectively. The results suggested that new chemistry insecticides with selective mode of action are effective on target pest and safer for the beneficial fauna when compared with old chemistries and pyrethroids. Pyrethroids used for PBW had knockdown effect and blindly kill the beneficial insects resulting a flare up of sucking insects in cotton. A wise selected sequence of pesticides can help to manage the population of P. gossypiella without resurgence or flare up of B. tabaci