Effective eco-friendly chemicals for pest control:study

Ludhiana, May 14: With insects and pests developing resistance to many conventional pesticides, scientists at the Punjab Agricultural University (PAU) are in the process of developing a new cost effective and eco-friendly ''chemistry'' to overcome the problems posed by the 'common' pests and insects.

''A new 'chemistry' is in the offing to control the old time pests and insects as well as reduce the use of insecticides and chemicals'' PAU Entomologist, Dr A K Dhawan who is involved in the research stated when contacted here today.

The process involves applying smaller doses of pesticides that are cost-effective and have long-term effects, he said. Even spray technology is gradually under-going a change in Punjab, as the new pesticides have different ''modes of action,'' climinating the pests in ways different than the traditional pesticides, he added.

According to Dr Dhawan these 'novel pesticides' could prove effective for controlling 'sucking' pests and American bollworm and pink bollworm.

Tracing the insecticide/ pesticide usage scenario in Punjab, Dr Dhawan said that the pesticide umbrella helped increase the food-grain production during the Green Revolution over the years but at the same time caused widespread damage to the enviornment, making the agro-ecosystem vulnerable to a new host of pests and insects and causing pesticide-residue in a variety of food stuffs.

''With the march of time, insect-pest problems have also increased in some crops following application of pesticides. This has resulted in higher consumption of pesticides, otherwise so necessary to maintain higher levels of production'',he added.

Consequently the PAU came face-to-face with a slew of new problems with the insects and pests having developed resistance to many plant protection chemicals,he added.Scientists have encountered the problem of resurgence of new pests, of pesticide-residues, outbreak of secondary pests and toxicity to natural enemies, he pointed out.

''Since agriculture is now in the cusp of change and so is the control of new pests and insects with new technologies'', he stated.

Refering to the widespread use of plant chemicals as indicated in his studies, Dr Dhawan pointed out approximately 55 per cent of food commodities in Punjab were found to be contaminated with pesticide-residues. The percentage of contamination in cereals due to use of DDT was observed to be eight per cent and six per cent, respectively, and percentage contamination due to DDT and Lindane in milk was two and 53 per cent respectively. Pesticide residues were also found in vegetables.

Since major emphasis in the initial years had remained on increasing foodgrain production to meet the country's needs, the consumption of pesticides also increased from 2353 million tones in 1955-56 to 41,020 million tones in 2003-04 in the country. The percentage share of pesticide consumption in Punjab was 17.9 in 2002-03, the studies observed.

''The American bollworm and whitefly during the last decade became very common pests of cotton'', Dr Dhawan stated. Today, with the adoption of Integrated Pest Mangement practices, insecticide usage has been reduced by 55 per cent on cotton crop, there-by cutting the cost of sprays by 38 per cent, but this needs further reduction, he added.

Refering to the presence of BT cotton in Punjab, Dr Dhawan said that it is likely to cause a dip of upto 70 per cent in the pesticide consumption in the Malwa belt. Similarly, in sugarcane adoption of bio-control strategies the pesticide incidence is reduced by 60 per cent and psticide use by 90 per cent.

Dr Dhawan said that even on vegetables several pests have developed multiple resistance to nearly all commonly used insecticides. ''We have regularly recorded several pests on a variety of plants and crops and armyworm has emerged as a pest of wheat, maize and sorghum and stalk-border is a new found pest in sugarcane',he added.

Likewise a new species of 'weevil and toka' are serious pests of wheat in rain-fed areas.'' However, as more area comes under assured irrigation, aphid will become a major problem'',the scientist stated.

UNI