Evaluation of Some Insecticides for the Control of the Citrus White Fly (Dialeurodes Citri Ashmead)

Dialeurodes citri is the most important pest of citrus in the hills of Uttar Pradesh. The effectiveness of several insecticides was evaluated against the eggs, nymphs and pupae of this insect on the trees of sweet orange variety Malta Common (Citrus sinensis Osbeck). Lime sulphur diluted with 20 or 25 parts of water and Esso tree spray oil (miscible oil) 1 per cent and 0.5 per cent were found highly effective against the eggs. DDT 0.2 per cent and endrin 0.02 per cent gave the best results in causing the mortality of nymphs. Dimethoate 0.03 per cent and formothion 0.03 per cent also proved effective against the nymphs. DDT 0.5 per cent consistently proved best in killing the pupae while fenitrothion, diazinon, parathion and methomyl all at 0.1 per cent also gave satisfactory control.