Kansas State University entomologists are reminding producers before they plant their Bt corn, to comply to EPA regulations. For Bt corn to remain an effective way to control corn borers, growers have a responsibility to abide by certain management guidelines provided, says Randy Higgins.

"Because Bt corn is so effective in controlling corn borers, there is concern that resistance to Bt could develop quite rapidly unless appropriate non-Bt corn refuge plantings are employed to maintain a susceptible population of corn borers," Higgins said. "As long as there are enough Bt-susceptible corn borers to mate with any potential survivors [potential Bt-resistant individuals] in the Bt corn field, the corn borer offspring are likely to remain susceptible.”

Higgins points to a recent survey that revealed over 70 percent of corn growers appeared to be abiding by Bt corn and non-Bt corn refuge proximity and acreage percentage restrictions. “That means that some are not fully complying with these guidelines based on the 2000 growing season," Higgins said.

Choosing not to implement an acceptable insect management plan means that you could be out of compliance and may make you subject to penalties, the entomologist added. Registrations granted by the EPA also may be withdrawn.

Higgins is urging farmers to abide the following management practices:

• Don't mix Bt corn and non-Bt corn seed in the seed hopper.
• If a split planter arrangement is used to establish the refuge, where some seed hoppers contain Bt corn and some non-Bt corn, refuge areas should be at least six rows wide to minimize the risk of resistance development, because corn borer larvae sometime move from plant to plant.
• Don't treat refuge corn with Bt-based insecticides. You may be treat with non-
• Bt-containing insecticides if economic thresholds are reached or exceeded.
• Your neighbor's corn cannot serve as your refuge.
• WThe refuge should be planted and managed in a manner similar to the Bt corn.