“The main worry is the stagnation in productivity at an average of 500 kg lint per hectare for the past five years. The gains have been unaffected by the sharp increase in area of Bt cotton, from 5.6 per cent in 2004 to 90 per cent in 2010,” [chief of the Central Institute for Cotton Research, Keshav Kranthi] warns. The yield was 463 kg per ha when the Bt cotton area was 5.6 per cent in 2004 and reached a mere 506 kg per ha when the area under Bt cotton increased to 9.4 million ha [...] More worrying, says Kranthi, is the increasing problems of sap-sucking insects, such as leaf hoppers, aphids, whiteflies and thrips, on the vast majority of susceptible Bt hybrids. [...] Insect populations of mealybugs, gall midges, mosquito bugs and safflower caterpillars, hitherto unknown are new concerns.