Through the 1980s and 90s, the bollworm caterpillar seemed intent on destroying the crops and livelihoods of millions of India鈥檚 cotton farmers. Bollworms were becoming increasingly resistant to insecticide, and hundreds of suicides by farmers prompted several government inquiries, the latest in 1998.
Now, thanks to a relatively low-tech approach to managing insecticide use that combines understanding of insect biology with that of human nature, cotton is once again profitable for tens of thousands of farmers.
The nationwide programme tells farmers which type of insecticide to use and when best to use it, so that during each of four month-long 鈥渨indows鈥� of the growing season, only one type of insecticide is used. The life cycle of the bollworm (Helicoverpa armigera) is about one month, so the offspring of any resistant insects that survive one round of insecticide are killed by a different one the next month.
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A network of 27 regional labs test which insecticides kill local bollworms, and district officers work out a spraying plan using software called Helibase. Farmers put the plan into action only when damage exceeds a certain threshold. Because farmers鈥� spraying habits tend to be heavily influenced by their neighbours, the scheme is introduced to whole villages at a time.
鈥淲e expect it to be sustainable because there are immediate benefits for farmers. Existence in India is too hand-to-mouth to expect people to do things for the public good,鈥� says Derek Russell of the University of Greenwich, UK, who masterminded the programme with Keshav Kranthi, of the Central Institute of Cotton Research in Nagpur, India.
鈥淭he biggest gain has been in human health,鈥� Kranthi says. A 2004 survey found that under the programme the number of farmers poisoned by insecticides had decreased roughly 10-fold, as they spray less insecticide and no longer use several kinds at once.
By 2005, three years after the programme was introduced across India, it had halved insecticide use by the 45,000 farmers then enrolled; 90,000 are now signed up, and thousands more follow the recommended practices. Yields were up by 11 per cent, and profitability by 75 per cent. In the Wardha district of Maharashtra, where the programme was introduced in 1997, common insecticides once again kill bollworms easily. Similar shifts in resistance are happening nationwide, but it is not known how much is due to the programme and how much to the growing awareness of resistance. The results are to be published this month by the US-based International Cotton Advisory Committee.
鈥淚nsecticide resistance management is very difficult on small farms in the Third World because of the numbers of farmers you have to contact, many of whom are not that well educated,鈥� says Alan McCaffery of Syngenta in Bracknell, UK, chairman of the Insecticide Resistance Action Committee, an international industrial body. 鈥淭his programme is the first one to have made an impact.鈥�
Russell and his colleagues have also introduced aspects of the programme in China and Pakistan via national farming information services. In Uganda, they have taken a different approach. 鈥淭here is no effective support structure in Uganda, so we are running 9000 demonstrations per year. By the end of 2007 we will have contacted every cotton grower in Uganda,鈥� he says.
