Bt cotton is not

Bt cotton is a genetically modified plant whose genes have been altered bythemanipulations to make it insect resistant through the introduction of Bt toxin gene. Bt toxin is produced by a bacterium called $Bacillus$ $thuringiensis$ (Bt). Bt toxin gene has been cloned from the bacteria which is expressed in plants to provide resistance to insects. Some strains of $Bacillus$ $thuringiensis$ produce proteins that kills certain insects like lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans(flies, mosquitoes). Bt cotton is made resistant to certain taxa of pests only (as mentioned above). It is quite likely that in future, some other pests may infest these Bt cotton plants.