GM food

Pests worm their way into genetically modified maize

Broadening of rootworm resistance to toxins highlights the importance of crop rotation.

Even with biotech crops, farmers still need to make use of age-old practices such as crop rotation to fight insect pests. That’s the lesson to be drawn from the latest discovery of resistance to the pest-fighting toxins added to maize — also known as corn.

According to a team led by Aaron Gassmann, an entomologist at Iowa State University in Ames, in some Iowa fields a type of beetle called the western corn rootworm (Diabrotica virgifera virgifera LeConte) has developed resistance to two of the three types of Bacillus thurinigiensis (Bt) toxin produced by genetically modified maize. Resistance to one type of Bt toxin has cropped up in the worms in recent years, but now there is a twist — the researchers have found that resistance to that type of Bt toxin also confers protection against another, more recently introduced type. Read more in Nature.