Northern corn rootworm appears to be adapting too well to the conventional corn/soybean rotation. Iowa State University Extension entomologist Marlin Rice reports that about 45-47% of these eggs wait for two years before hatching. This is up from less than 1% having extended diapause in the mid 1960s, he says.

“The exception to the exception now is some eggs not hatching for three years,” he says. “This insect is changing its biology to accommodate our rotations,” he says.