North Bengal’s lush tea estates, especially in the Dooars region, are facing a serious crisis. A massive outbreak of looper caterpillars, a pest known for damaging tea leaves, has spread across nearly all gardens in the area. Tea planters warn that this could lead to a 10 per cent drop in production in the 2025 season alone. West Bengal’s tea output fell by 21 per cent by July 2024 compared to the previous year.
And with the looper invasion continuing into August, further 10 per cent losses are feared. Nationally, pests like looper caterpillars cause India’s tea industry to lose nearly 147 million kg of tea each year, costing about Rs. 2,865 crore. Already the gardens are mired with multiple problems, including climate change, erratic rainfall and nonreplacement of age old bushes, but the looper pest attack with no sign of a let up poses another threat for the gardens of North Bengal. In Gathia Tea Garden (Nagrakata), the situation has taken a grim turn. Manager Navin Mishra reported that they are now able to collect only 15,000 kg of leaves daily, down from the usual 25,000 kg.
At Kurti Tea Garden, manager Rajesh Rungta is also battling the caterpillar crisis. The looper caterpillar – mainly Hyposidra talaca and H. infixaria – along with similar insects like Biston and Ectropis species, have been a recurring problem in Assam and North Bengal since 2009. These pests go through a full life cycle, but it is during the larval stage that they eat through tea leaves, especially during March–June (pre-monsoon) and again in winter. Climate change has made things worse. The Dooars region has seen erratic rainfall, long dry spells, and warmer winters, all of which help looper populations grow quickly. A 100-year weather study shows that winter minimum temperatures have increased by 1–1.2 °C, and forest cover loss has also contributed to these pest outbreaks.
Tea gardens now use up to five or six types of pesticides in rotation to control pests like loopers, thrips, and tea mosquito bugs. But with only two approved insecticides under the Plant Protection Act, the results are poor. Many pests are becoming resistant to these chemicals. Dr. Trina Mandal of the Tea Research Association says one of the approved insecticides is nearly useless now, and the other is proving ineffective too. Ram Avatar Sharma, Secretary of the Dooars Branch of the Indian Tea Planters Association, agrees that traditional solutions are no longer working.
Workers at Karbala Tea Garden say they have no choice but to handpick the loopers from the bushes. The damage is widespread. In Alipurduar district, both northern and southern areas have been hit. Severely affected gardens include Ranichera, Leesh River, Oashabari, Dimdima, Hantabari, Subhashini, Bich, Barobari, and many more across Kalchini, Malbazar, Dalgaon, and Kumargram blocks. To fight back, Jaydeep Phookan, Secretary of TRA, has urged the Tea Board of India to approve a new pesticide, Solomon, under emergency rules. TRA has also recommended biological control methods, such as using natural fungi like Beauveria bassiana and Metarhizium anisopliae, which have shown up to 90 per cent pest mortality in lab tests. However, the financial burden on tea gardens is increasing. Labour costs already make up 60 per cent of total production cost, and rising pesticide expenses are making things worse.
Though prices have gone up Assam tea saw a 15 per cent rise, and West Bengal tea rose by 7 per cent – this is not enough to balance the sharp fall in output and rising costs. The Tea Association of India has written to state labour ministers, seeking help to support workers and planters during this crisis. The looper caterpillar outbreak, fuelled by climate change, overuse of chemicals, and ecological imbalance, is now a serious threat to the economic future of North Bengal’s tea industry. Without urgent support, updated policies, and scientific solutions, thousands of workers and planters risk losing their livelihood – and one of India’s most iconic industries could face long-term decline.
(The writer is a former professor, Chanchal College, Malda.)