The document, "100 Years of Bacillus thuringiensis: A Critical Scientific Assessment," follows the experience with Bt since it was discovered over 100 years ago as a cause of disease in Japanese silkworms. Bt insecticides, made of bacterial spores and protein crystals, have been applied to crops in spray products since the 1940s. In 1987, researchers discovered that the insecticidal crystal protein (ICP) genes from Bt could be introduced into plants to produce pest-resistant crops. It is now estimated that 12 million hectares, or about 29,652,000 acres, of insect-protected crops with Bt ICPs are planted worldwide each year. Corn and cotton are most common, but the release of Bt rice, soybeans, canola and some fruits and vegetables is expected soon.
Bt crops, the report says, have many positive effects. Reducing insect damage with insecticidal proteins reduces fungal toxins in the food supply, while better crops improve farmers' livelihood. Replacing chemical pesticides has reduced toxic hazards to the environment and to farm-workers. Yet concerns related to Bt crops include the potential for harm to organisms other than the insects targeted by Bt, the development of Bt-resistant insects, the possibility of toxicity or allergenic properties in Bt crops or their pollen, and the consequences of gen
Contact: Andrea Lohse
American Society for Microbiology