An ambiguous decision by Frito-Lay Inc. not to accept genetically modified corn is putting new pressure on farmers at the brink of the planting season, even though the snack food giant is not willing to promise consumers that its products will be GM-free.

While Frito-Lay's decision will not have a significant impact on the size of the market for Bt corn, farmers contacted by BioCentury find the move disturbing if not hypocritical. Nevertheless, many said they would lower the acreage they devote to Bt corn this year, even if going back to conventional corn means resuming heavy use of pesticides.