North Bengal Tea Gardens Battle Dual Threats: Pests Devour Crops Amidst Climate Chaos

Prof. SANTANU BASU

North Bengal's iconic tea industry, a lifeline for thousands of families and a significant contributor to the state's economy, is confronting an unprecedented crisis. A devastating surge in looper caterpillar infestations, combined with erratic weather patterns fuelled by climate change, are threatening to cripple tea production and plunge the region's lush gardens into ‘progressive decline’.   This dual assault is not only severely hampering daily tea plucking but also raising fears of a significant drop in overall production, jeopardizing livelihoods and the future of a cherished industry.

The emerald expanses of the Dooars region, the heart of North Bengal's tea cultivation, are now a battleground against the voracious looper caterpillar. Tea planters are issuing dire warnings, predicting a minimum 10% drop in production for the 2025 season alone. This comes on the heels of an alarming 21% decline in West Bengal's tea output by July 2024 compared to the previous year, with further losses feared as the looper invasion continued into July even. The scale of the threat is immense; nationally, pests like looper caterpillars already cost India's tea industry approximately 147 million kg of tea annually, translating to a staggering loss of about Rs. 2,865 crore. With the advent of early monsoon in the country, the workers hoped for washing out the pests from the leaves  but consecutive dry spells in North Bengal ‘helped’ thriving the pests dealing the veritable blow to the workers and planters alike.

The situation on the ground is grim. At Gathia Tea Garden in Nagrakata, in Alipurduar district,the Manager,Navin Mishra, reported a drastic drop in daily leaves collection,  hovering a usual 25,000 kg to a mere 15,000 kg. Similar battles are being waged at Kurti Tea Garden, where manager Rajesh Rungta struggles against the relentless caterpillar onslaught. Workers at Karbala Tea Garden, like Himadri Banerjee, are resorting to desperate measures, handpicking loopers from the bushes in a futile attempt to save the crop.

The workers, in a note of severe depression, showed sack full of caterpillars instead of leaves. The damage is widespread, affecting numerous gardens across Alipurduar district, including Ranichera, Lish River, Oashabari, Dimdima, Hantabari, Subhashini, Bich, Barobari, and many others in Kalchini, Malbazar, Dalgaon, and Kumargram block along Sankosh river in the eastern parts of dooars bordering lower Assam.

But Subhasishini Tea garden in Kalchini with acres after acres land faced the worse attack from Greenfly Helopeltis looper and other harmful bacteria. In this garden which was famous for its product, is now confronted a dire reality – production is apprehended to come down by not less than 72% compared to previous two years. In 2021, this garden registered a record yield in North Bengal; the  yield  would now be lowered by 92% compared to 1991.

On an average the Dooars gardens are set to lose 22% of the yield, according to Ram Avatar Sharma, Secretary of Indian Tea Planters Association, Dooars chapter. The loss of production left the workers into despair and distress, now deprived of daily wages; till 7 June, two fortnight’s wages turned arrear. Unlike other gardens where workers are ups in arms for wages, the workers of Subhashini Tea Gardens bearing the ordeal with the planters wait for resumption of tea leaves plucking and production and desisted from demanding the daily wages.

The looper caterpillar, primarily Hyposidra talaca and H. infixaria, along with species like Biston and Ectropis, has been a persistent menace in Assam and North Bengal since 2009. These pests, in their larval stage, relentlessly devour tea leaves, particularly during the crucial March–June (pre-monsoon) period and again in winter.

Compounding the pest crisis is the alarming impact of climate change. The Dooars region has endured erratic rainfall, extended dry spells, and unusually warmer winters – conditions that create an ideal breeding ground for looper populations to explode. A century-long weather study confirms a distressing increase of 1–1.2°C in winter minimum temperatures, and the shrinking forest cover further exacerbates these pest outbreaks, disrupting natural ecological balances.

This year's rainfall statistics paint an equally gloomy picture. June 2025 saw only half the rainfall compared to the previous year, despite June and July typically being the peak of the rainy season. The Indian Meteorological Department (IMD) Sikkim Chapter reported that June 2024had registered 721.1 mm of rainfall, while June 2025 recorded a mere 321.3 mm. Similarly, July, which experienced heavy downpours last year, has seen only sporadic and insufficient rain this year across North Bengal. This prolonged dry spell, an unusual phenomenon for the region, has caused widespread concern. Even if torrential rains arrive in the coming days, experts believe the deficit cannot be fully recovered. Rain meters installed in various tea gardens confirm significant shortfalls compared to previous years, with rain-fed days in June decreasing from 25 to 18, and overall maximum temperatures in Dooars rising by an alarming 2 degrees Celsius.

According to Dr. Shyam Varghese, Chief Advisory of the Tea Research Association (TRA), North Bengal Chapter, the eastern parts of Dooars are most severely affected by the dry weather and intense pest attacks, leading to a 10% to 25% lower yield in gardens like Madarihat-Birpara, Kalchini, and Kumargram. Beyond loopers, other pests such as Helopeltis, Red Spider Green Fly, and Thrips are also widely attacking the gardens putting both the workers and planters into dire strait.  Furthermore, diseases like bacterial blight, fusarium die-back, brown blight, and red rust are hitting the gardens hard. Dr. Trina Mandal, a Tea Research Association (TRA)  terrain branch officer, estimates that June's production alone is expected to be lowered by no less than 25% due to the combined impact of warming temperatures and pest attacks, as the sustained high temperatures hinder the flourishing of buds and tea leaves.

The TRA's latest report squarely attributes the decline in tea yield to climate change. In June, Dooars registered a decline of 6.65 lakh kgs, standing at around 58 lakh kgs, while the hills saw a yield drop of 1 lakh kgs, settling at 15.20 lakh kgs instead of 16.26 lakh kgs. Although some Darjeeling Himalayan tea growing zones have shown a marginal improvement in tea yield compared to their Dooars counterparts, planters remain frustrated by the declining quality of the prized first flush, a direct consequence of climate vagaries.

In a desperate bid to control the pests, tea gardens are now rotating up to five or six types of pesticides, targeting loopers, thrips, and tea mosquito bugs. However, with only two approved insecticides under the Plant Protection Act, their efforts are largely ineffective, and many pests are developing resistance. Dr. Trina Mandal notes that one approved insecticide is "nearly useless," and the other is also proving ineffective. Ram Avatar Sharma, Secretary of the Dooars Branch of the Indian Tea Planters Association, concurs that traditional solutions are no longer working.

Jaydeep Phookan, Secretary of TRA, has urgently appealed to the Tea Board of India to approve a new pesticide, Solomon, under emergency rules. TRA has also advocated for biological control methods, such as the use of natural fungi like Beauveria bassiana and Metarhizium anisopliae, which have demonstrated promising results, showing up to 90% pest mortality in lab tests.

However, the financial burden on tea gardens is escalating relentlessly. Labour costs already constitute a staggering 60% of total production expenses, and rising pesticide expenditures are further exacerbating the crisis. While tea prices have seen a modest increase—Assam tea by 15% and West Bengal tea by 7%—this rise is insufficient to offset the sharp fall in output and mounting operational costs. The Tea Association of India has written to state labour ministers, seeking immediate assistance to support both workers and planters during this dire period.

The North Bengal tea industry, already grappling with challenges like erratic rainfall, the need for bush replacement, nature’s betrayal, the impact of the Russia-Ukraine war, and the influx of counterfeit tea from Nepal, now faces its gravest threat yet in the form of this rampant looper caterpillar outbreak, exacerbated by climate change and ecological imbalance. Already, 14 of Darjeeling's 87 tea gardens have been forced to close, with the former President of the North Bengal Tea Producers Association, Satish Mitruka, actively seeking prospective buyers for these sick units. The renowned tea gardens in Dooars straddling both in Alipurduar and Jalpaiguri district, namely Sonali, Raipur, Ramjhora, Dalsingpara, Lankapara, Madhu and Turturi, have been closed since past while several others known for higher quality of teas,  namely Ambutia, Rangmuk, Cidar, Mundakothi, Nageri, Duteria, Balason, Peshak, and Singtam  in Darjeeling Himalayas have also been closed.

Without urgent support, updated policies, and robust scientific solutions, thousands of workers and planters in North Bengal risk losing their livelihoods. The City of Joy's famed golden brew and one of India’s most iconic agricultural sectors are at a critical juncture, facing the very real possibility of long-term decline unless immediate and decisive action is taken. The time to act is now, before the economic future of North Bengal's tea industry is irrevocably withered.

(Views are personal. Email: santanub12@rediffmail.com)