The disputes have left some proposed plants waiting, mired in lawsuits; a few have given up.

“There is a campaign of sorts that is seeking to slow and preferably to stop the growth of the ethanol industry,” said Matt Hartwig, a spokesman for the Renewable Fuels Association, a trade group based in Washington. “We have to get through a barrage of mud pies to get our message out.”

These are not the better-known philosophical opponents to ethanol, those who question the efficiency of corn-based ethanol as an energy source, blame ethanol for rising food prices, or disagree with the federal subsidies that have long held up the industry.

These people are farmers. Or they know a farmer. Or their grandfather was a farmer and, as in so many farm families, ethanol has meant new hope for the fading towns built on corn fields. The biggest complaints are cousins of the gripes brought about by proposed paper mills, landfills, prisons and the like: an increase in noise, traffic, odor, emissions and demand on the water system.

“No, no, no, we’re not against ethanol production whatsoever,” said Lonnie Nation, who lives near New Castle, Ind., where he and others have posted signs, filed a lawsuit and were going door to door this month to stop a new plant. “But if you put it where they want to, you’re going to be squeezing all our homes between an ethanol plant and a prison. What will that do to home values?”

Some experts say the local protests reflect a new anti-ethanol mood spurred by a slow but steady drumbeat of negative attention on the industry. Across the Midwest, questions about ethanol have been raised by environmental advocates, livestock owners have complained about soaring prices for corn feed and farmers have fretted about how expensive some farmland has become.