Abstract: Volatile blend of cotton leaves extracted in Steam distillate was found to play some decisive role in insect attractions when evaluated through various field and laboratory bioassays. TLC and GC-MS analysis and identification of steam distillate of highly susceptible cotton variety S-12 and resistant variety Ravi showed some qualitative and quantitative differences. Susceptible varieties indicated the presence of greater potential of mono-terpenes ( -pinene myrcene, limonene and ocimene etc), while resistant variety Ravi possessed more -pinene. An unidentified compound showed 96% peak intensity in S-12 and 34% in Ravi. Cis form of caryophyllene was present in S-12 while Ravi possessed trans- caryophyllene and -terpeniolene was only present in Ravi.