Transgenic cottons producing Cry toxins from Bacillus thuringiensis (Bt) were prepared for control of lepidopteran pests and were first commercially grown in Australia, Mexico and the USA in 1996. As of 2007, a total of six additional countries (Argentina, Brazil, China, Colombia, India, and South Africa) now grow Bt cotton on a total production area of 14 million hectares. To control these polyphagous herbivores, farmers routinely use large amounts of broad-spectrum chemical insecticides, killing many non-target arthropods in the process. However, since heliothine caterpillars have a history of developing resistance to almost all the insecticides used for their control, alternative control methods have to be developed. One option is the use of insect resistant genetically engineered (GE) varieties expressing lepidopteran active Cry proteins derived from the soil bacterium Bacillus thuringiensis. So-called Bt cotton plants are grown commercially since 1996. Most of today¿s varieties express the Bt protein Cry1Ac either alone or in combination with Cry2Ab, protecting plants from damage by the main pest Lepidoptera.