Abstract

                                The study aimed to evaluate the comparative efficacy of six newer insecticidesas a foliar application against the whitefly, Bemisia tabaci on cotton varietyCO17 in two seasons’ field experiments from december 2020 to july 2021at Department of Cotton, Tamil Nadu Agricultural University, Coimbatore.Insecticides were sprayed when the whitefly population reached theeconomic threshold level (ETL) i.e., 4-5/3 leaf. The results revealed thatflonicamid 50% WG @ 75 g a.i. ha-1 recorded 81.99 % reduction in meanpopulation of whiteflies after three rounds of spray at fifteen days interval. Theorder of relative efficacy of test insecticides based on the mean populationof whiteflies were, flonicamid 50% WG 75 g a.i. ha-1 > dinotefuran 20% SG@ 25 g a.i. ha-1 > clothianidin 50% WDG @ 25 g a.i. ha-1 > thiamethoxam 25% WG @ 50 g a.i. ha-1 > pyriproxyfen 10% EC @ 50 g a.i. ha-1 >diafenthiuron50% WP @ 300 g a.i. ha-1 > untreated control. Flonicamid 50% WG @75 g a.i. ha-1 recorded increased yield of 2380 kg ha-1 and 2040 kg ha-1over untreated control (1865 kg ha-1 & 1570 kg ha-1) in first and secondexperiment, respectively.

Key words : Newer insecticides; Bioefficacy; Whitefly; Bemisia tabaci; Cotton; Flonicamid