As farmers approach late middle age, they are less likely to plant corn that produces Bt, a protein that kills corn rootworms and European corn borer insects that feed on plant tissues, said lead researcher Corinne Alexander, a Purdue agricultural economist.

The study also found farmers experienced in biotech crops are more likely to plant Bt corn hybrids.

"What we found was that age was a significant predictor in Bt corn

adoption," Alexander said. "We found as producers get older and gain

experience they are more likely to adopt Bt corn rootworm, but once they reach about age 48 they become less likely to adopt the technology."

The findings are published in AgBioForum.