Before U.S. farmers even began planting this year's corn crop, agriculture economists and grain traders predicted it would be a volatile growing season. And, it has been. We're only about a month into the season and corn futures prices are already swinging wildly at the Chicago Board of Trade.

Traders attribute the volatility to the dreaded "D" word. In this case, "D" means drought. A severe drought that is centered over Alabama is creeping farther north, into Indiana and Ohio. Illinois is now abnormally dry.

But, the threat of a drought isn't the only reason corn prices are bouncing up and down like popcorn. Ethanol is the other. Increased production of the corn-based fuel has been nudging corn prices higher for months. With enthanol pushing demand for corn higher, economists have been warning what could happen if the nation's corn crop is threatened by bad weather or disease. That is what we are seeing right now.

At this point, farmers could still harvest a big crop this fall. Growers planted about 15 percent more corn this spring than last. On top of that, there is still about one billion bushels of corn left over from last year. But, we are now living in a time when food producers and fuel producers are vying for the same commodity. So, anything that even threatens that commodity will up its price.

Some energy analysts that I have interviewed over the past couple of years have seriously questioned the idea of trading food for fuel. They argue that whatever savings ethanol might bring to consumers will be offset by higher food prices.

Terry Francl, chief economist for the American Farm Bureau Federation, thinks corn yields this fall will be lower than originally expected. How low those yields will be and how high corn prices could go remains to be seen. So, too, is the reaction consumers might have to higher prices at the grocery counter.