Leaf reddening problem is intensified in most of the cotton growing states of India.However since introduction of bt cotton,it's incidents are increasing despite the fact that it's existence has been documented even in British rule in India.One major change since last 10-12 years is shifting of farmers from non bt cotton to by cotton cultivation.Does this means that there is something in Bt gene that renders the plant roots relatively less efficient in absorbing nutrients esp magnesium sulphate.May be over exploitation of soils since last 50 years without substitution of Minor elements is one of the reason.In north western India light to medium soils are most prone to this malady which starts only after boll setting i.e 90-100 days after sowing.