Isolated findings of resistant rootworms in Iowa emphasize that planting a refuge is more critical than ever for maintaining the durability of Bt corn, a Purdue Extension entomologist says.
Bt corn does not kill all larva that feed upon it, and very slight feeding damage from corn rootworm is typical, said Christian Krupke. But after researchers at Iowa State University were alerted to high levels of feeding damage in some fields, they began to test Bt corn hybrids that expressed the Cry3B1 toxin. They found that rootworms from those fields were able to survive exposure in the lab.
“This is not a cause for alarm for Indiana producers, and it was something that we suspected would occur eventually,” Krupke said. “Producers should keep doing what they are doing for now as the vast majority of Bt continues to perform well for producers. This is more of a warning to be vigilant”
Currently, other Bt toxins appear to be effective against the pest.… Continue readingRead More »