Calcutta, May 4: Poor rain has raised the spectre of pest attack on tea bushes.
A similar situation had arisen in 2010, though then it was heavy rain that caused pests to attack leaves.
The insects thrive both during drought and heavy rain, both of which leave the bushes weak.
“The problem this time is that we had a late drought. It rained in March and the bushes threw leaves. As it does so, it expends energy and becomes weak also. No rain leaves the bushes weakened and it falls prey to pests,” said C.S. Bedi, managing director of Rossell India.
“In 2010, excessive rains brought in pests. In 1999, we had a similar drought and crop was down 40 per cent. This year, crop could be down 40 per cent in April and May,” he said.
Tea plants in India are attacked by chewing pests such as bunch caterpillar, looper and red slug caterpillar. Sucking pests such as the thrips affect crops between January and July, while helopeltis may attack between February and November. Apart from these, crops are attacked by mites such as the red spider.
“What we are seeing this time is unprecedented. Pests that appear during the rainy season are coming into gardens now. The rain helps wash down most of these pests which is not happening because of the drought. With the underground water layer also going down, irrigation is becoming an issue. The plant roots are also unable to draw water themselves as a result,” said Bijoy Gopal Chakraborty, president of the Confederation of Indian Small Tea Growers Associations.
Timely rainfall also helps in washing away the excess fertiliser sprayed to control bugs. Regulations have been tightened against the indiscriminate use of pesticides to reduce the maximum residue limit in leaves.
The Tea Board has beefed up norms on the use of pesticides to improve the acceptability of the crop in key export markets.
According to Sam Varghese, chief advisory officer, North Bengal Regional R&D Centre of the Tea Research Association, thrips suck on the cell saps, which leaves the plant weakened.
The Tea Research Association has projects underway to create resistant varieties of seeds. Once finalised, the seeds will be multiplied and distributed in the industry.
Darjeeling has fared better against pests because of the higher elevation.