Survey Reveals B.t. Use Age Bias

A Purdue University study found that as farmers’ approach late middle age they are less likely to plant corn that produces Bacillus thuringiensis (B.t.) toxin, which kills corn rootworms and European corn borers that feed on plant tissues.  The 2004 study, based on surveys and discussions with about 1,000 Indiana farmers who grew at least 200 acres of corn, also revealed farmers experienced in biotech crops are more likely to plant B.t. hybrid corn, while some growers are less inclined to use these varieties because they find planting parts of their fields in non-B.t. refuge corn a hassle.  As young farmers become more comfortable with biotechnology their adoption of genetically modified corn seed increases.

Older farmers who've never planted B.t. hybrids aren't likely to start.  "What we found was age was a significant predictor in B.t. corn adoption," said Corinne Alexander, the study’s main researcher.  "We found as producers get older and gain experience they are more likely to adopt B.t. corn, but once they reach about age 48 they become less likely to adopt the technology."  The reasons, Alexander said, include time and profit potential.  "For those farmers who are much closer to retirement, they receive a much smaller benefit from trying something new because they are only going to be farming for, say, another five or 10 years."   

Indiana is an interesting case study for genetically modified corn adoption because the state has areas with severe, moderate and low corn rootworm problems.  "How a farmer controls corn rootworm in Indiana really depends on what sort of pest pressure they face," Alexander said.  "In southern Indiana, most farmers wouldn't treat for it at all because there are very few corn rootworm larvae in that part of the state.  In the moderate region in northeast and central Indiana, farmers may use soil insecticides or seed treatments for control.  In the high pressure northwest corner of Indiana, most farmers use soil insecticides and some use seed treatments."  Twenty-one percent of Indiana's corn was planted in biotech varieties in 2004 compared to 47 percent nationally, according to the U.S. Department of Agriculture.  "Producers now have four options" in the corn rootworm fight, Alexander said.  "They've got the no treat option.  They've got the seed treatment option.  They've got the soil insecticide option.  And, now, they have the B.t. corn rootworm option." 

The Purdue study also found that preventing non-B.t. corn from being pollinated by nearby B.t. corn crops is a factor in producer adoption of the biotech seed.  In addition, some farmers indicated that the extra effort in planting non-B.t. refuges in or near their Bt corn crops discourages them from planting the corn rootworm-resistant seed.  "We also did a series of focus groups with producers.  We asked them to agree or disagree with the statement, 'I will not plant a corn rootworm resistant variety because of the refuge requirement.'  What was surprising was farmers who strongly agreed with the statement were also significantly less likely to adopt corn rootworm corn."  Farmers who plant B.t. corn are required by the U.S. Environmental Protection Agency to plant 20 percent of their acreage within, around or adjacent to those biotech crops in non-B.t. corn hybrids.  (www.aganswers.net,  2/17/06).

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