Resistance Management Curricula
Bt plant hybrids are engineered to produce an insecticidal protein from, Bacillus thuringiensis, a naturally occurring soil bacterium. There are many strains of Bt each toxic to a limited group of insects. For example, one Bt strain may be harmful to beetle larvae but at the same time safe to butterfly larvae. Bt has been used for over 50 years in its topical form by organic farmers and home gardeners. In the 1990's Bt was first engineered into plants to provide protection from insect pests. Due to the increase use of Bt in biotech crops, there was concern that insect pests would quickly become resistant to Bt. Because of Bt’s importance to both organic and non-organic farmers, it was decided necessary to create a set of strategies to reduce the occurrence of resistance in crop pests.
These strategies are widely referred to as Insect Resistance Management.
The most widely accepted strategy of Insect Resistance Management for Bt hybrid crops is refuge management. Refuge management is the practice of planting a percentage of your crop in non-Bt hybrids so that a population of Bt susceptible insects is maintained. Susceptible insects from the refuge mate with the resistant survivors from the Bt portion of the field. Since resistance to Bt is a recessive trait in most target insect groups, the genes for susceptibility will be passed onto their offspring.
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