By JIM SUHR

Associated Press

ST. LOUIS (AP) -- The corn harvest is in the homestretch in several key Midwest farming states where the nation's worst drought in decades is now clouding the prospects for the winter wheat crop.

The U.S. Drought Monitor's weekly update released Thursday shows that nearly two-thirds of the lower 48 states remained mired in some form of drought during a seven-day period ending Tuesday.

Conditions in Iowa, the nation's biggest corn producer, remained unchanged, with three-fourths of the state still in the extreme or exceptional drought -- the two worst classifications. Nearly all of Nebraska still falls under those two categories.

The U.S. Department of Agriculture says 69 percent of the nation's corn crop has been brought in from the fields. That's more than double the average rate of the previous five years.

Copyright 2012 The Associated Press.