Description

Amongst various species of insect pests attacking the cotton crop, the sucking insect pests always remained a limiting factor. Among these sucking insects Jassid (Amrasca devastans Dist.) has great importance. Jassid is a very serious sucking pest of cotton which causes serious and significant yield reduction in susceptible cotton varieties. There a lot of research is carried out on the Physico-morphic characters and their effect on the sucking insect pests of non Bt-varieties but on the Bt-varieties there is no such type of research is carried out up till now. So it is needed that to carry out the research on the Bt-varieties. The present study will be conducted to know the resistance against Jassid in 10 available Bt-cotton varieties with the objective to know responses of these varieties towards the attack of this sucking insect pest. Physico-morphological characters like hair density, hair length and width of leaf lamina and number of gossypol glands of the plant leaves and along with weather factors i.e. temperature, humidity and rainfall will be correlated with the attack of Jassid on these selected varieties.