The chequered history of Bt cotton in India — marked by pest resistance and farmers' suicides — has polarised opinions over the technology, reports TV Padma. 'Bt and the beast' is how cotton scientist Keshav Raj Kranthi refers to the controversial genetically modified cotton so widely planted in India. The 'beast' is the American bollworm — a moth larva that devours cotton bolls — while Bt is its nemesis, a protein crystal from the bacterium Bacillus thuringiensis.