Behavioural hormoligosis in oviposition preference of Bemisia tabaci Gennadius on egg plant

Abstract

Abstract The study tests the impact of sublethal dose on oviposition preference in Bemisia tabaci (Gennadius) on treated brinjal plant using the multiple-choice test during 2019 and 2020 season. Diafenthiuron 50% WP (150, 210, and 300 g a.i./ha), fenpropathrin 30% EC (50, 70, and 100 g a.i./ha), thiamethoxam 25% WG (25, 35 and 50 g a.i./ha) and deltamethrin 2.8% EC (7.5, 10.5 and 15 g a.i./ha) were repeatedly sprayed on brinjal plants (var. Hisar Shyamal) growing in pots. The effectiveness of these insecticides was assessed based on the preference of B. tabaci (whitefly) for oviposition on treated plants. Additionally, this study tested variations in the biochemical components of treated brinjal leaves and their relationship to the propensity for oviposition. The results revealed that fenpropathrin 30% EC and deltamethrin 2.8% EC treated plants were more preferred by whitefly for oviposition. Maximum number of eggs were laid on sublethal dose of fenpropathrin30% EC treated plants at 50 g a.i./ha (42.93 eggs/ leaf) and deltamethrin 2.8% EC at 7.5 g a.i./ha (39.57 eggs/leaf) followed by fenpropathrin30% EC at 70 g a.i./ha (39.02 eggs/ leaf) compared to untreated control (26.74 eggs/leaf). An almost similar trend of results was observed in the repeated experiment in 2020. The results obtained from biochemical studies revealed that all the insecticidal treatments caused a reduction in total sugars and amino acids except lower dose of fenpropathrin 30% EC, and deltamethrin 2.8% EC. Also, all the insecticides caused a reduction in total phenol content and brought significant changes in crude protein content. Hence, fenpropathrin 30% EC and deltamethrin 2.8% EC treated brinjal plant is nutritionally superior host for whitefly and led to behavioural hormoligosis in oviposition preference by whitefly. The results of this study would benefit agricultural practitoners and farmers.