Overall, it’s been a very hot and humid week across northern IL as we begin to move out of the heat dome that has been sitting over us for the past five days. This week alone, we’ve added nearly 200 GDUs from the heat wave in DeKalb County, with seasonal totals reaching 959 GDUs. Isolated rainstorms have brought some relief to drought-stricken areas. Some fields are still showing signs of stress with “pineapple” corn, but overall, the corn crop has looked better this past week. With temperatures expected to remain high as we enter July, I expect early-season stunting or growth delays in both corn and soybeans to be largely overcome.

Corn has begun to shoot up across most fields I scouted. Lake County still has some shorter corn, but as you head further west along the I-88 corridor, the stands get taller—reflecting the pattern of rainfall and the impact of late-spring cool temps. Corn is between V6/V7 and V9/V10 depending on planting date and is nearly 5′ tall in some fields. Much of the drought stress from last week has been alleviated thanks to healthy weekend rains across northern IL, along with isolated storms this week. More storms are expected, and it would be great if some of the drier fields could catch them. I haven’t seen any tar spot or other fungal diseases so far this season, but with rising moisture and temperatures into the 80s, we may begin to see it in the lower canopy. Tar spot has been found in western IL, and you can track its spread at the Crop Protection Network:
https://cropprotectionnetwork.org/maps/tar-spot-of-corn

Soybeans are progressing well. On Wednesday, 6/25/25, I saw the first field beginning to flower as we enter the R1 stage. Fields range from third trifoliate to R1 flowering, depending on environmental conditions and planting dates. The further west you go, the taller the beans, with Lake County again showing some of the shorter growth. Overall, I haven’t seen any early-season diseases, and most visible damage is from herbicide burn following post applications.

Wheat had a strong week of ripening after a cool May and early June. Disease pressure remains low in the fields I scouted, with full heads present. The grain is still quite wet in the head, and plants need more time to mature and dry down. If warm temperatures continue in the upper 80s, I’d expect harvest to begin in some fields around or just after the Fourth of July.