Pink Bollworm Resistance to GM Cotton in India

Pink Bollworm In Cotton In India (2009 – Ongoing)
In 2009, Monsanto entomologists detected and, ultimately confirmed, pink bollworm resistance to our first-generation single-protein (Bacillus thuringiensis) Bollgard® I cotton in four states in Western India. We worked closely with farmers to contain the resistance and implement effective insect resistance management programs. Today, Bollgard II – a second-generation cotton seed that contains two different Bt proteins – has replaced Bollgard I in all of our cotton seed markets. It provides additional and more robust protection against the bollworm, and no instances of insect resistance have been observed.


Monsanto’s first-generation single-protein Bollgard I cotton (MON531) uses a naturally occurring Bt protein (Cry1Ac) to control insect pests. While resistance is natural and expected, the detection of pink bollworm resistance to Bollgard I in 2009 posed a significant threat to the nearly 5 million farmers who were planting the product in India.

We quickly equipped a team of experts to help farmers contain resistance to the Bt protein in Bollgard I cotton and to monitor the impact throughout India.

During testing, researchers determined that pink bollworm resistance to the protein was confirmed in four districts in the Indian state of Gujarat – Amreli, Bhavnagar, Junagarh and Rajkot. Among the factors that may have contributed to pink bollworm resistance are limited refuge planting and the early use of unapproved Bt cotton seed, planted prior to GEAC approval of Bollgard I cotton, which may have had lower protein expression levels. No insect resistance to Bollgard I has been confirmed outside these districts, and extensive monitoring throughout all of India continues to find that the resistance has been contained successfully.

The findings in Gujarat reaffirm it is essential to regularly monitor and scout fields throughout the season for insect presence and plant appropriate non-Bt refuge when planting Bt cotton seeds.

Measures to delay resistance are critically important. Adopting measures such as need-based application of insecticide sprays during the crop season, and proper management of crop residue and unopened bolls after harvest will help limit insects in cotton fields. Examples of such practices include tillage and cattle grazing to minimize the survival and spread of pink bollworm.

Research shows that pink bollworms are completely susceptible to the combination of two proteins expressed in second-generation in Bollgard II, which most Indian farmers choose to plant today.

We know it is imperative to stay ahead of insect resistance, and research continues to determine best management strategies to ensure the planting of refuges for Bollgard II and future products. In addition, we are committed to developing new high-performing products to give farmers a wider choice of insect-control technologies. We are currently working on a three-protein Bt cotton technology, and are open to collaborating with other technology providers in India to develop products that use the best available technologies for the benefit of Indian farmers.