Illegal herbicide-tolerant Bt (HTBt) cotton now accounts for about one-fourth of India’s cotton acreage, particularly in Central India, hurting the legal seed business and driving a black market for glyphosate, a study has found.
Seed associations and experts have called for the immediate legalisation of HTBt technology, saying it could help farmers improve productivity and support the seed industry.
The study, titled "Unauthorized Cultivation of HTBt Cotton in India: Extent, Drivers & Implications," found that 98.2% of field samples carried at least one genetically modified trait. Of these, 41.9% contained "quadruple stacks" with four transgenes, including Vip3A, an insect-resistance gene that has never been approved in India.
The study said high manual weeding costs and labour shortages have driven some cotton farmers to illegally cultivate HTBt cotton. The genetically modified crop is tolerant to glyphosate, allowing farmers to spray the herbicide to control weeds without harming the cotton plants. Non-HTBt cotton, in contrast, requires manual weeding, significantly increasing production costs.
Unauthorized cultivation of HTBt cotton covered 6.5 to 7.2 million acres during the 2025-26 Kharif season, accounting for 24% to 30% of India’s total cotton area. This has sustained an informal seed market estimated at Rs 1,500 crore, according to a field study conducted by the South Asia Biotechnology Centre (SABC) with support from the Federation of Seed Industry of India (FSII) and the National Seed Association of India (NSAI).
The findings suggest that farmers are bypassing formal channels and paying a premium "technology fee" in the black market to ensure operational survival and crop insurance.
"Unchecked use of unapproved genes and unmonitored glyphosate spraying could lead to the emergence of resistant pests and weeds that devastate cotton productivity," stated Dr C.D. Mayee, President of the Indian Society for Cotton Improvement and SABC. "Stewardship is only possible when the technology is legal."
The study identified labour shortages as a major factor behind the shift to HTBt. Glyphosate use costs approximately Rs 750–850 per acre, compared with Rs 12,000–15,000 for manual weeding. Glyphosate use increased by 26% in a year, from 27,721 kilolitres in 2024-25 to 35,642 kilolitres in 2025-26. Much of it is now sold through underground networks in 20-litre drums. Meanwhile, sales of legal Bollgard-II seeds fell by 22.3% between 2022 and 2026.
Maharashtra is the epicentre of HTBt adoption, with 58% of farmers using the technology, rising to 76% in Yavatmal. Telangana, at 66%, and Andhra Pradesh, at 49%, are also seeing high adoption, with the figures reaching 82% in Mahabubabad and 75% in Kurnool. Rajasthan has minimal HTBt use but is witnessing rising demand for illegal BG-III seeds to combat pink bollworm.
As the seed is not covered by the Seeds Act and the Seed Control Order, farmers lack quality assurance and recourse when it fails. The study calls for a time-bound policy overhaul and warns that further delays could worsen concerns over biosafety, resistance, seed quality and intellectual property.
