No-tiller's yields dropped as much as 14 bushels per acre when rootworms were not controlled.

It pays to control corn rootworm pests, at least in the fields of no-tiller Gary Sommers. He has been part of a University of Wisconsin Extension service study monitoring fields near Clinton in south central Wisconsin to help determine if corn rootworm treatments are worth the expense.

"The first year that they monitored yields and compared treated vs. untreated fields, we noticed an 8-bushel-per-acre advantage on the treated fields," says Sommers, who added the second-year data was even more dramatic. "Last year, the data showed a 14-bushel-per-acre advantage on the treated fields."

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Knowing precisely how much rootworm damage was costing him helped Sommers justify his seed treatments.

"Sometimes it's difficult to quantify how much yield loss is due to rootworm damage," he says.

With corn prices at the time of the study around $3 per bushel, the yield advantage seen by Sommers justified the treatment costs. In fact, at corn prices of $5 per bushel, the yield advantage Sommers saw in the 2 years of the study would have helped him gross $40 to $70 more income per acre to use toward a corn rootworm product, whether an insecticide or in-plant trait.

"In the 2 years that the university has collected data in fields using soil-applied insecticides in corn, it has proven that it pays to protect my corn from rootworm damage," he says.

Sommers no-tills 1,500 acres of mostly corn and soybeans…