Insecticidal activity of botanical oils and other neem-based derivatives against whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) on cotton

Abstract

The insecticidal and phytotoxicity activities of oils from castor (Ricinus communis), pongamia (Pongamia glabra), sesame (Sesamum indicum), neem (Azadirachta indica) and neem based formulations in combination with a detergent Powder as a surfactants (0.1%) were studied against adults of Bemisia tabaci at their peak activity period during 2016–17 and 2017–18 seasons under laboratory and field conditions. Among the oils, castor oil caused a reduction of whitefly populations by 55.4 & 64.2 and 40.5 & 42.8% under laboratory and field conditions, respectively during both the years, pongamia oil 58.4 & 51.7 and 44.9 & 39.2%, sesame oil 45.5 & 56.4 and 30.8 & 36.9%. Neem oil and its formulated products were reported to be comparatively less effective in reduction of whitefly population after chemical treatments i.e. difenthiauron 50 WP (76.2 & 81.5 and 63.5 & 55.2% under laboratory and field conditions, respectively). Phytotoxicity observed after application of recommended doses of castor, pongamia, sesame and neem oil and its formulated products did not cause any problem on tender cotton leaves. The detergent based solutions were difficult to mix and oily layers appeared after mixing, hence mixing the oils and detergent solutions with sticker Triton-X-100 @1.0 ml/l is more effective and easy to apply on cotton plants.