Bt cotton contains a gene from a common soil bacterium, Bacillus thuringiensis, that produces an insecticidal protein in the plant that kills major cotton pests such as the cotton bollworm and the pink bollworm. These are serious pests that affect not only cotton, but maize, vegetables and other crops. With a variety of hosts and the ability to migrate over long distances, large outbreaks are common. The cotton bollworm is estimated to cause losses of as much as $2 billion annually.
Around the world nearly 13 million smallholder farmers are now growing Bt cotton. Burkina Faso, the largest cotton producer in Africa, adopted Bt cotton on a commercial scale in 2008. A year later with yields up to 50% higher than conventional cotton varieties, it also reduced the number of sprays required from an average of 8 down to at most 2. From 2003 – 2005, Bt cotton was reported to increase farm incomes within the range of $79 to $154 per hectare depending on seed costs and year and improved yields by about 21.3%. By 2012, cotton farmers in Burkina Faso grew Bt cotton on more than 300,000 hectares. Reviewing the benefits of Bt cotton in Argentina, Brazil, Mexico, India and South Africa, the World Bank found that yields increased between 11% and 65%, and and profits grew as much as 340% with significantly reduced pesticide use and pest management costs.