Extreme heat forecast into next week for southern Illinois isn't likely to help corn and soybeans stressed by weeks of drought.

University of Illinois crop expert Emerson Nafziger says triple-digit heat will send plants into a sort of survival mode.

National Weather Service forecasters say parts of southern Illinois could see highs of 100 or more through July 4th.

Nafziger said corn in some areas may already be damaged enough to trigger insurance payments to farmers.

The Illinois Department of Agriculture said earlier this week that almost a quarter of the state's corn crop is in poor or worse condition.

The U.S. Drought Monitor indicates most of Illinois is experiencing at least moderate drought.