Efficacy of thiamethoxam against whitefly, Bemisia tabaci (Gennadius) under open field conditions in okra

Abstract

A field experiment was conducted at Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar, India during the summer season, 2021-22 to evaluate a neonicotinoid, thiamethoxam against whitefly, Bemisia tabaci (Gennadius) along with other new molecules. Among the various doses of foliar application thiamethoxam, sprayed twice at an interval of 10 days on okra, resulted in 87-90 per cent reduction over untreated control. Seed treatment with thiamethoxam 30% FS formulation was also effective against B. tabaci upto 45 days from seed treatment. Foliar application of thiamethoxam (50 g a.i. per ha) gave highest yield and ICBR ratio and it was in line with the appliaction of thiamethoxam 37.5 and 25 g a.i. per ha. All the tested insecticide formulations were found to be
safe for coccinellid beetles, except dimethoate 30 EC @ 600 g a.i. / ha, which have negative effect on coccinellid beetles as recorded in the okra ecosystem in comparison to the higher dose of thiamethoxam 25 WG (double dose @ 50 g a.i.ha-1). Results also showed that none of the insecticide formulations had phytotoxicity effect in okra ecosystem.