Charlie Nye, Associated Press
Water from the Wabash River engulfs this farm in southern Indiana, another farming area hurt by flood.

NEW YORK — Floods that have inundated the Midwest could reduce world corn supplies and drive food prices higher, at a time when Americans are already stretching their grocery budgets and people in poor countries have rioted over rising food costs.

The U.S. government will report later this month on how many acres of corn were lost to floodwaters. But farmers and agriculture experts already say the toll appears grim, with thousands of acres probably destroyed in the region that grows most of the world's corn.

"It's not a very good picture at all. We're looking at possibly a good reduction in acres if a lot of this crop remains underwater," said Chad Hart, an agriculture economist at Iowa State University. "There's still hope, but it wanes with each rainstorm."

The disaster has drawn comparisons to the 1993 floods that displaced thousands of people and wiped away vast swaths of the heartland's agriculture. At the time, about 18 bushels per acre of corn were destroyed, "and everybody is reporting that this year is worse," said Jason Ward, grains analyst at North Star Commodity in Minneapolis.

The most recent floods have sent corn prices soaring past $7 a bushel for the first time, up from about $4 a year ago. Prices shot to a record for a seventh straight day Friday, climbing as high as $7.37 a bushel on the Chicago Board of Trade.

Floodwaters also hurt soybean crops, sending prices to near all-time highs. Wheat, oats, rice and other food commodities were damaged, too.

Corn prices could jump further if floodwaters don't recede soon, experts say.

"We've got some major price volatility ahead the weaker this crop gets," Hart said.

In Iowa, the country's top corn producer, about 9 percent of the anticipated crop either hasn't been planted because farmers can't get into their fields, or it needs to be replanted because it's waterlogged, said Roger Elmore, a corn expert at Iowa State.

That's about 1.2 million acres of corn — almost 1.5 percent of the country's anticipated harvest — that may produce only a fraction of its potential yield. Rain continued falling in much of Iowa on Friday, and it's already late to be planting corn.

"It's Noah's Ark-like conditions out there...and if you replant now you're going to get much lower yields," said Vic Lespinasse of grainanalyst.com in Chicago.

Corn prices have shot up more than 80 percent in the last year because of rising energy prices and surging global demand for biofuel and livestock feed. But excessive rainfall in the Midwest has pushed prices up nearly 20 percent in the last month alone.

Climbing commodity prices worldwide have hit Americans in their wallets and touched off riots in Haiti, Senegal, Egypt and other poor countries.

A weak corn crop could only make things worse. Livestock owners will probably have to slaughter more cattle, hogs and chickens to offset the rising cost of corn-based animal feed, leading to more expensive beef, pork, chicken, eggs and dairy products.

Other livestock owners may switch to cheaper feed made from barley or wheat, adding to already high demand for those grains.

"In some cases, hog and cattle farmers are seeing feed prices double," said Iowa corn farmer Russell Meade, who also sells hay for livestock. "Those guys are going to be put in a financial squeeze."

It's the same gloomy story for U.S. ethanol producers, who are already being threatened by high corn prices and political pressure to roll back or eliminate federal subsidies.

Many smaller ethanol producers might have to idle plants until corn prices fall, said Michael Swanson, an economist for Wells Fargo & Company.

Farmers were expected to plant 86 million acres of corn in 2008 — an 8 percent drop from last year. After the flooding began, the Department of Agriculture reduced its projected corn harvest to 11.7 billion bushels, a 10 percent drop from last year.

On June 30, the USDA will release an updated estimate on the size of the 2008 corn crop, and many expect it to be significantly smaller than the initial numbers.