Pink Bollworm Threat for Bt Cotton
Science & Technology
31st Oct, 2023
According to a recent study, the Pink Bollworm in India has grown to become worse than the American bollworm and affecting significantly to cotton farmers.
- This is the fourth story in a series about pink bollworm attacks on Bt cotton in the North Zone, comprising Punjab, Haryana and Rajasthan.
Bt Cotton introduction in India:
- Bt cotton was introduced to India in 2002 after its success in the United States and Australia in 1996.
- Before that, the American bollworm had become the biggest threat to cotton crops as it had developed resistance to synthetic pyrethroids, organophosphorus and carbamates (group of insecticides).
- From 1985-2002, it caused heavy economic losses to farmers in all 11 cotton-growing states of India.
What is Bt Cotton?
- Bt cotton is an insect-resistant transgenic crop designed to combat the bollworm.
- The first two generations of Bt have seen introduction of ‘Cry1Ab’ and ‘Cry2Bc’ genes from the soil bacterium, Bacillus thuringiensis (Bt), into the cotton seed, which make the crop resistant to the attack of pink bollworm.
Pests getting resistant to Bt Cotton:
- Indian farmers have faced consistent losses of Bt cotton crops due to pink bollworm attacks since the mid-2000s, when scientists found that the insect had become resistant to the genetically modified variety of cotton.
- Bacillus thuringiensis (Bt) cotton, or Bollgard-I, was introduced to protect the crop against all three species of bollworms (American, spotted and pink bollworms) as it was encoded with Cry1Ac toxin.
- In 2005, scientists with the Indian Agricultural Research Institute started monitoring if pests were growing resistant to Bt cotton. A year later, Bt cotton was encoded with Cry2Ab gene for improved resistance against the American bollworm.
- But in 2008, researchers found unusual survival of pink bollworm in Amreli district of Gujarat, indicative of the pest’s resistance to Bt cotton. Later, through scientific study, in 2009-10, scientists confirmed pink bollworm’s resistance to Cry1Ac gene in four districts of Gujarat.
- In 2017-18, widespread pink bollworm infestation was reported in Maharashtra and the southern states.
- Then in 2021-22, a pink bollworm outbreak was reported in Punjab and Haryana.
- By 2023, resistant populations of pink bollworm to Bt cotton were established in the North Zone including north Rajasthan districts.
About Pink Bollworm:
- The pink bollworm, scientifically known as Pectinophora gossypiella, is a destructive pest that primarily infests cotton plants.
- It is named "pink" bollworm due to the pinkish hue of its larvae.
- These insects feed on the cotton bolls, damaging the cotton crop and reducing its yield and quality.
- Pink bollworm larvae burrow into the cotton bolls, where they feed on seeds and plant tissues.
- In recent years, pink bollworm infestations have posed a significant threat to cotton cultivation in various regions, particularly in India.
- Farmers have faced challenges in managing these pests due to their ability to develop resistance to conventional pesticides.
- To combat the pink bollworm, integrated pest management strategies, including the use of genetically modified Bt cotton varieties and the deployment of sterile insect release programs, have been implemented.
- These efforts aim to reduce the impact of pink bollworm infestations and safeguard cotton production, which is crucial for the textile industry and livelihoods in affected regions.