Some researchers believe pest monitoring will become more difficult as full-scale commercialization of seed mixtures in transgenic insecticidal corn begins.
“Seed mixtures may make insect-resistance management (IRM) risky because of larval behavior and greater adoption of insecticidal corn,” says David Onstad, a University of Illinois professor.
Block refuges present a different suite of risks because of adult pest behavior and the lower compliance with IRM rules expected from farmers, he adds.
“It’s likely that secondary pests not targeted by the insecticidal corn, as well as natural enemies, will respond differently to block refuges and seed mixtures,” he says.
The risk-management approach to corn pest management has provided tangible benefits to producers, such as the role Bt hybrids have played in reducing European corn borer numbers. But Onstad says that approach tends to ignore many aspects of integrated pest management — such as monitoring pest levels and concentrating treatments when or where appropriate — because there is an assumption that most pests are controlled throughout the season, regardless of pressure levels.
Onstad also believes growers will have fewer choices in what hybrids they grow.