Evaluation of neonicotinoid insecticide against whitefly, Bemisia tabaci (Gennadius) in okra ecosystem

AbstractField experiment was conducted at RPCAU, Pusa, Samastipur, Bihar during the Spring-Summer season, 2023. Ten treatments consisting of thiamethoxam 30% FS (@ 1.7, 2.6, 3.4 g ai kg-1 seed; T1, T2, T3) and thiamethoxam 25% WG (@ 25.0, 37.50, 50.0 g ai ha-1; T4, T5, T6), pyriproxyfen 10 EC @ 50 g ai ha-1 (T7), imidacloprid 17.8 SL @ 20 g ai ha-1 (T8), standard check of dimethoate 30% EC at 600 g ai ha-1 (T9) were evaluated against whitefly, Bemisia tabaci (Gennadius). Among the various doses of foliar application of thiamethoxam 25 WG sprayed twice at an interval of 10 days on okra, the treatments T6, T5 and T 4 were statistically at par in terms of their effectiveness (86.6, 84.0, and 82.2% reduction over untreated control) followed by T8(78.1%), T9(73.7%) and T7(69.0%). The okra seed treated plots with thiamethoxam 30% FS formulation were also found to be effective against B. tabaci upto 45 days from seed treatment. Foliar application of thiamethoxam (50 g ai ha-1) gave highest yield and ICBR and it was in line with the application of thiamethoxam 37.5 and 25 g ai ha-1. All the tested insecticide formulations were found to be safe for coccinellid beetles, except dimethoate 30 EC @ 600 g ai ha-1, which have negative effect on coccinellid beetles. Results also showed that none of the insecticide formulations have phytotoxicity effect in okra ecosystem.