Insect pest resistance

Resistance is a natural biological response to repeated use of the same control technology. As with weeds, resistance can also occur with insects and is not unique to biotechnology-derived plants.

Bacillus thuringiensis (Bt), is a naturally occurring bacterium that is found in soil, and produces a toxin that can work as an insecticide. Bt has been widely used as an insecticide for farmers, organic and conventional alike, since the 1930’s. In recent years, plants have been developed to produce a Bt protein, which allows the plant itself to resist certain insect pests, which can reduce the need for a farmer to spray their crop with an insecticide.

Bt corn hybrids have been commercially available in Canada since 1997 and have become a valuable tool in controlling key pests, such as the European corn borer and corn rootworm. Scientists across North America, in both the public and private sectors, agree that these two pests could develop resistance to the Bt proteins under conditions of continued use.

Stewardship Plans

In an effort to prevent resistant insect populations in plants that have built-in pesticide genes, the Canadian Food Inspection Agency (CFIA) requires that each Bt corn registrant implement an insect resistance management (IRM) strategy with farmers.

These IRM plans require a refuge strategy, which involves planting a portion of the field with Bt corn plants, while maintaining another part of the field with non-Bt corn (a "refuge"). This promotes the survival of susceptible insect populations, who mate with resistant individuals in the insect population and delay the development of a resistant population. This strategy has been endorsed by leading scientists to reduce the risk of insect populations developing a resistance to Bt corn.

At Syngenta, we work to educate corn growers regarding rootworm control strategies and trait stewardship, including effective agronomic and insect-resistance management practices. These practices include rotating crops, planting refuges as required, and rotating or combining multiple modes of action against the target pest.