Michal L. Rosenoer, a policy analyst with the environmental group Friends of the Earth, said the end of the tax credit showed that “ethanol is no longer a sacred cow.”

“The end of this giant subsidy is a win for taxpayers, the environment and people struggling to put food on the table,” Ms. Rosenoer said. “Production of ethanol, with its use of pesticides and fertilizer and heavy industrial machinery, causes soil erosion and air and water pollution. And it means that less land is available for growing food, so food prices go up.”

Ethanol proponents eventually accepted expiration of the tax credit without putting up a big fight.

“We may be the only industry in U.S. history that voluntarily let a subsidy expire,” said Matthew A. Hartwig, a spokesman for the Renewable Fuels Association, a trade group for ethanol producers. “The marketplace has evolved. The tax incentive is less necessary now than it was just two years ago. Ethanol is 10 percent of the nation’s gasoline supply.”

In response to a question about how the loss of the subsidy might affect prices and supply, Mr. Hartwig said: “We don’t expect the price of corn to fall or rise just because the tax incentive goes away. We will produce the same amount of ethanol in 2012 as in 2011, or more.”

Representative Jeff Flake, Republican of Arizona, said, “With record deficits and a ballooning national debt, it was ludicrous to expect taxpayers to pay billions to prop up a mature industry that should be able to fend for itself.”

Senator Dianne Feinstein, Democrat of California, said the ethanol industry had enjoyed “a trifecta, a triple crown” of federal support. Federal law requires that certain minimum amounts of renewable fuels like ethanol be blended into gasoline. Refiners received the tax credit for doing so. And the government imposed a tariff on imported ethanol, protecting the domestic industry.

The tariff, like the tax credit, expired Saturday. But the requirement to use increasing amounts of ethanol in gasoline continues.