The advantages of using Bt cotton over non-Bt varieties are huge. Since introducing it over a decade ago, there has been an 80% reduction in the use of chemical pesticides previously required to control bollworms. This not only means safer working operations for growers but is beneficial for the environment as well.
But a recent US-French study published in the journal Nature Biotechnology indicates that harmful crop pests are becoming resistant to the most popular type of genetically-modified, insect-repellent crops.
The researchers reviewed data from 77 studies across eight countries and found five of 13 examined pest species have a degree of in-field resistance to the bacterial insecticide. In 2005, it was just one.