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Pests damage tea bushes in Assam

- Caterpillar migrated from West Bengal a few years ago
A butterfly which metamorphosed from the looper caterpillar. Telegraph picture

Jorhat, July 22: A caterpillar, believed to have migrated from West Bengal, is devouring tea leaves with a vengeance in the gardens of Upper Assam, triggering concern among planters.

The “new pest in town”, looper caterpillar (hyposidra talaca), has severely infested the Doomdooma belt of Tinsukia district with Bordubi, Hukonguri, Dikom and Mohanbari gardens bearing the brunt of the attack.

Romesh Boruah, head of the Tea Research Association’s Upper Assam Advisory Centre at Dikom in Dibrugarh district, told The Telegraph today that the hyposidra talaca was common in West Bengal, where it had first hit the gardens about seven to eight years ago.

It was noticed in Upper Assam a couple of years ago but its attack has been severe this year, making it a menace to the tea bushes of late, he added.

Boruah said although a few other caterpillars of the hyposidra species were common in Upper Assam gardens, the hyposidra talaca had been noticed on such a large scale for the first time this year.

The senior tea scientist said the biggest problem with this pest was that it devoured tea leaves on a large scale and in a very short time, unlike the others of its kind which are common in the area.

“This particular caterpillar has a short life span of about 30-35 days, unlike the other caterpillar pests which have a life span of about 72-75 days as it devours tea leaves at a much faster rate and on a larger scale compared to other tea pests,” he said.

Another problem with this particular pest, Boruah said, is that spraying of chemicals is not the only solution to tackle the menace.

“It requires chemical, physical and mechanical practices,” he said.

Chemicals have to be sprayed in cracks, crevices and holes of trees that provide shade to tea bushes where the hyposidra talaca lays eggs and on the ground to control young caterpillars.

Lime coating has to be put on the trunks of such shade trees which grow to a height of 2-3 metres from the ground, and surviving mature caterpillars have to be hand-collected.

“Apart from all these methods, torches have to be lit at night to kill the moths,” he added.

Another pest which has attacked the tea bushes in Upper Assam this time, though not as severely, resulting in crop loss, is the aulacaspis rosarum.

This pest damages tea bushes by sucking out the juice from the leaves.

“Although the attack in not as severe as the caterpillar, this pest can severely damage plants heavily infested by it, resulting in major crop loss,” another tea scientist said.