After 8 years of field trials, genetically modified cotton seem to be a success in combating pink bollworm. Biotech cotton is genetically modified to include the Bacillus thuringensis Bt gene, also used in maize and rice, conferring resistance to insects. When pink bollworms feed on the cotton, the Bt toxin is released in their gut and they die, bringing insect population under control, which in turn reduce the necessity to use chemical pesticides.

Since widespread adoption of Bt cotton in 1997, insecticide use on Arizona's cotton crops is down 60 percent. The reduction in chemical pesticide use saves growers about $80 per acre. According to the Arizona Agricultural Statistics Bulletin, the value of Arizona's cotton crops for 2004 was estimated at $207 million.

Good for the environment, for sure. But is this a viable solution in the long-term?One concern in using Bt crops is the emergence of resistance in the insect population. In an upcoming issue of the Proceedings of the National Academy of Sciences, scientists from The University of Arizona report the results of their long-term monitoring of the Bt cotton fields to determine if pink bollworm has gotten resistant to Bt. So far, although Bt resistant bollworms were found, they were still rare. The farming practice of planting patches of traditional -wild-type- cotton among the Bt cotton helped curb the emergence of resistance. Team leader Bruce Tabashnik warns,

"It's not that pink bollworm can't beat Bt toxin, but that it hasn't beaten Bt toxin so far."

He adds,

There's a new variety Bt cotton now available that has two different Bt toxins. The team's next step will be to determine how to best use that combination of toxins to stay one step ahead of the pink bollworms.

Monsanto, which funded this research, continue to prove to have all (market) eventualities covered, eh?

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Photo credit: Timothy Dennehy, University of Arizona