Control of Empoasca lybica, de Berg., On Cotton in the Anglo-Egyptian Sudan

Abstract

A short account of the life-cycle and symptoms of damage of the cotton Jassid, Empoasca lybica, de Berg., is given. In the initial cage experiments it is shown that DDT emulsion was superior to the copper compounds used. Experiments on the residual toxicity of DDT and “Gammexane” sprays are described. Tests with DDT emulsion showed that very young cotton is injured by emulsion containing as little as 0·025 per cent. DDT, but that emulsions containing up to 0·5 per cent. DDT can be used with safety on plants which are two months old. A coarse DDT suspension caused severe leaf distortion, but a fine suspension used later was quite safe at the concentration used.