Estimation of Loss Due to the Attack of Cotton Jassid (Amrasca Bigutulla Bigutulla (Ishida) On Gossypium Hirsutum. Cotton

Estimation of loss due to the attack of cotton jassid, Amrasca bigutulla bigutulla (Ishida) was done by comparing the yield in the protected and unprotected crop in 22 experiments con-ducted during 1975–80 in hirsutum cotton. It was found that on an average, the jassid caused a reduction of 114kg of seed-cotton/ha which can be saved by spraying the crop with dimethoate (0 18 kg ai/ha) once or twice on the appearance of second grade injury symptoms of yellowing and curling along the margins of the leaves. Loss in yield due to jassid attack varied from 108kg/ha in cultivar F 414 which is highly tolerant, to 160 kg/ha in J 205, which is highly susceptible to the attack of jassid.