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.