Surinder Sud: Nibbling away at yield, profit

The menace of whitefly and other pests on cotton crops is exacerbating for want of appropriate technical guidance to farmers as well as the wrong choice of pesticides and seeds

It is not the first time that the whitefly, a pernicious pest, has ravaged cotton crop in northern states, especially in Punjab, Haryana and surrounding areas. Nor is it the only enemy of this cash crop. Many pests and diseases hit the crop at various stages of its growth. Bollworms, notably the American bollworm (Helicoverpa armigera), which used to inflict heavy damage in the past, were tamed by developing the transgenic Bt-cotton hybrids. But other pests such as jassids, aphids and thrips have continued to attack the crop. Cotton growers, therefore, have to remain vigilant against the pest build-up and initiate appropriate remedial measures when their population crosses the threshold level.

However, the pest control measures have to be strictly according to the advice of farm experts. Otherwise, these can turn counterproductive, as has been the case this year. Most farmers sprayed the crop with whatever insecticides were recommended by the pesticide dealers. Many of them sprayed the chemicals more often than it was necessary - even 10 to 12 times - or used spurious or wrong pesticides. They also did not adopt the correct method of spraying. To kill whiteflies, the chemicals need to be applied on the underside of the leaves where these insects dwell, and not on top, as is usually done. As a result, whiteflies remained unaffected.

According to cotton scientists, repeated application of insecticides during the early and mid-season of the crop cycle often leads to a resurgence of whiteflies. For, such indiscriminate spraying tends to destroy even the useful entities such as spiders, which are natural enemies of whiteflies and other pests. The scientists recommend a judicious mix of bio-pesticides and other pest-control measures to achieve best results. Neem oil, fish oil resin soap and neem-seed kernel extract provide a relatively more effective control of whiteflies, they say.

The Nagpur-based Central Institute for Cotton Research (CICR) has designed some novel, easy-to-operate devices that trap whiteflies. These include the Whitefly Adult Suction Trap and the Yellow Sticky Trap. The suction trap, for which the CICR has applied for a patent, is a power-operated, shoulder-mounted, adjustable contraption that sucks and entraps adult whiteflies present on the underside of cotton leaves. It does not harm either the cotton crop or the predators and other natural enemies of the whitefly.

The sticky trap is an effective scouting mechanism to alert farmers on the impending pest menace, apart from capturing the insects. When tied to the trouser on the outer thigh of the person engaged in routine weed control or other field operations, it draws whiteflies and holds them to the adhesive strip.

The menace of whitefly or, for that matter, other pests, notably the sucking pests, seems to be gradually exacerbating, chiefly for want of appropriate technical guidance to the farmers as well as the wrong choice of pesticides and seeds. The findings of a survey conducted by the CICR in 18 major cotton-growing districts of Maharashtra between 2012 and 2014 bears this out. Although over 300 transgenic Bt-cotton hybrids are available in the market, farmers normally opt for those recommended by the dealers or private companies, rather than the ones best suited for them. Some of the available Bt-hybrids are also relatively less vulnerable to the whitefly. But farmers are either unaware of them or unable to access their seeds. Unsurprisingly, therefore, nearly 64 per cent of the respondents of the survey reported that the selected hybrids were not giving expected yields.

However, regardless of the high risk of losses due to pests, unfavourable weather, price fluctuations or other factors, cotton growers are disinclined to stop growing this crop as it remains more lucrative than its alternatives. The Commission for Agricultural Costs and Prices has observed in its kharif price policy report for 2014 that out of the 14 major kharif crops, cotton yielded the highest returns, estimated at Rs 31,790 per hectare. However, the situation might change if the problems facing the cotton cultivation are not suitably addressed.
surinder.sud@gmail.com