The tea industry in Assam and West Bengal is grappling with a severe greenfly infestation, which has emerged as a major agronomic threat over the past two years, significantly impacting tea yield and quality. The pest outbreak, now spreading across key tea-growing belts, has raised alarm among planters, scientists, and industry stakeholders.

“This sap-sucking insect has inflicted considerable damage on tea bushes, especially during the dry months,” said Joydeep Phukan, secretary of the Tea Research Association (TRA). “The impact has been staggering, with yield reductions ranging from 11 per cent to as high as 55 per cent in affected gardens.”

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Greenflies primarily target tender, young leaves, crucial for producing high-quality tea, causing visible symptoms like uneven leaf surfaces, downward curling, and browning at the edges. This pattern of damage, known as “rim blight,” compromises both leaf quality and quantity. The situation becomes particularly dire during the second flush season (May to July), a period that accounts for over 30 per cent of the industry’s annual revenue due to heightened demand and premium pricing of second flush teas.

Mr Phukan attributed the pest’s aggressive spread to recent climatic changes, particularly rising temperatures and declining rainfall patterns. “Earlier, greenflies were mainly active between May and July. But now, due to shifting climate conditions, we’re seeing infestations persist throughout the year. This signals an alarming adaptation of the pest to environmental stress,” he explained.

Adding to the concern is the potential emergence of mutated or more resilient greenfly strains, particularly in tea estates located near international borders. Experts fear that these variants may be further intensifying the infestation and complicating control measures.

Despite the application of pesticides approved under the plant protection code (PPC)—including Quinalphos 35EC, Thiamethoxam 25 WG, Deltamethrin 2.8EC, and Thiacloprid 21.7 per cent —results have been largely ineffective. “Greenflies are rapidly developing resistance to conventional pesticides,” Mr Phukan noted. “Planters are left with limited options, and the current solutions are no longer sufficient.”

In response, scientists at the Tocklai Tea Research Institute, under the Tea Research Association, are actively exploring both chemical and biological alternatives. One promising candidate is Chlorfenapyr 10 per cent SC, which has shown effectiveness against greenflies in initial trials. However, the compound is yet to receive a label claim for tea from the Central Insecticides Board, a mandatory requirement before it can be legally used in commercial tea cultivation.

“With no time to lose, the tea industry is urgently seeking new, science-backed pest management strategies,” Mr Phukan said.

“If left unchecked, this infestation could have long-term economic consequences for thousands of tea growers and workers across Assam and Bengal.”