A controversy has broken out in the Indian tea industry over the Central Insecticide Board (CIB) permitting the use of dimethoate, which was banned by CIB in 2020, to overcome the problem caused by the tea mosquito bug (Helopeltis theivora) in tea plantations.

As per the minutes of the 446th meeting of the Registration Committee (RC) of CIB (CIB-RC) held recently, an ad-hoc approval for the use of dimethoate, considered to be a highly toxic organophosphorus compound, to counter the spread of tea mosquito bug has been accorded for one year.

The committee has, however, directed the industry to submit the residue data which would then be examined by the concerned technical experts to justify the continuance of usage.

Also read: Farm sector’s pesticide dilemma

The move to allow the controversial chemical comes on fears of India’s tea production dropping significantly following a sharp spike in incidences of major pests including tea mosquito bug (Helopeltis theivora) and Looper Caterpillar.

The Tea Board of India is advocating the adoption of an integrated pest management strategy which includes chemical and non-chemical methods and best agricultural practices proposed by the Tea Research Association (TRA).

According to estimates close to 147 million kg (mkg) of the crop is lost every year, causing annual losses to the tune of ₹2,865 crore to the Indian tea industry. The CIB-RC has permitted the chemical allegedly at the behest of a section of the industry.

Saurav Pahari, Chairman, Tea Board of India, said the long-term sustainable solution would be to adopt an integrated pest management strategy to address the problem.

“At the behest of a section of the tea industry, the CIB-RC has allowed the use of this chemical for a period of one year. There has been a significant amount of crop loss that has been reported due to incidence of pest attacks. We have always advocated integrated pest management strategy and best agricultural practices proposed by TRA. We routinely send out advisories through our field officers,” Pahari told BusinessLine.

Industry worried

A section of the industry has raised concerns over allowing the usage of dimethoate and its impact on the environment as well as human beings.

According to PK Bezbaruah, former Chairman of Tea Board, it would be regressive going back to the usage of a pesticide which was banned in 2020. The industry should work towards adopting best cultural practices by going in for regular pruning of bushes, increasing the nutrition status of bushes etc to address the issue of pest.

“Attempting 100 per cent control of pests would be catastrophic to the environment. One has to accept that in production some amount of crop will be lost to certain environmental factors. Our task as scientific agriculturists should be to minimise this while ensuring that there is less harm to the environment and to people consuming the product,” he said.

One of the solutions to overcome the pest attack would be to go in for early plucking. But that would require an adequate number of people to pluck leaves. However, in some gardens, particularly in south India, there are not enough people to do this so the plucking cycle is fairly long, said N Lakshmanan, a senior planter in a south Indian estate. The industry should go in for machine plucking or robotic plucking to overcome the problem, he said.

However, some of the planters feel that so long as the time interval of plucking post spraying the pesticide is maintained, it should not be an issue and the industry should be allowed to use certain chemicals to tackle the growing menace and virulence of some of the pests. “It should be understood that nobody will use chemicals unless we are pushed to the wall as it is expensive and entails a high cost for application/spraying. But sometimes you need such chemicals once a while to break the cycle of attacks,” said Vikram Singh Gulia, MD & CEO, Amalgamated Plantations.  

Allow new-gen chemicals

Rising temperatures and prolonged rainless periods due to climate change have created the perfect conditions in North India estates including Assam and West Bengal, for large-scale attacks of pests and diseases in the tea plantations.

The cost of plant protection in tea plantations in north India has increased manifold over the past two decades reaching to as high as ₹25,000-30,000 per hectare. This has had a negative impact on the viability of operations leading to lower exports and global competitiveness, said a statement by TRA.

The Indian tea industry uses pesticides which are approved by the CIB along with the guidelines issued by the Tea Board of India through its Plant Protection Code and Good Agricultural Practices listed by the Tea Research Association. “Currently there are only seven pesticides which are approved for use in India by CIB’s RC, making it difficult for tea growers to effectively control tea mosquito bugs and tea looper. The availability of a narrow range of limited chemicals has led to resistance build-up in pest populations. Additionally, there are restrictions on the use of pesticides in tea due to revision of MRLs in the EU, creating barriers to trade or processed teas from India to the EU,” TRA said.

TRA Tocklai has, therefore, recommended integrated pest management strategy, which includes chemical and non-chemical method, for both pests. Plant protection scientists at TRA have been evaluating several new molecules/pesticides against the major pests through products available with the Indian pesticides manufacturers and have submitted bio-efficacy and residue studies through the manufacturers to the CIB’s RC. “We have been asking for (allowing usage of) new generation chemicals, which are basically green molecules. We have proposed four such chemicals of which one has already been approved and the remaining is likely to receive approval in the next two-to-three months,” said Joydeep Phukan, Secretary, TRA.