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

Field 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.