Illinois Crop Update | September 11, 2026

Steve Brand – Commercial Ag Specialist

DeKalb County

Soil Conditions: Near Normal

Cooler and wet conditions have moved in across northern Illinois. Light rain and heavy morning dews have propagated some late season disease in both corn and soybeans as we start to enter wide-scale senescence and harvest.

Soybeans in McHenry and DeKalb counties are producing large amounts of pods, as well as filling those pods very well. I expect many soybean fields to have high yields. I have seen mostly foliar late season diseases such as SDS and Septoria leaf spot, but nothing of major concern that will slow down soybean pod fill. Fields with earlier maturities are well into senescence as well.

Corn is finally starting to show some disease with the prolonged leaf tissue wetness, and lower temperatures that we have seen in September. Tar spot, northern corn leaf blight, and even some late season southern rust are being found in fields. Many corn fields are starting to fire and die down, as well as hitting black layer, or physiological plant death. Disease at this point will mostly go on to determine inoculum load for next season, as well as assist in drying down plant material for harvest.

Overall, we are steadily marching towards harvest, and hoping for some great drying and harvest weather to finish out the season

Russ Higgins – Commercial Agriculture Educator

Grundy County

Soil Conditions: Mildly Dry (soil is drier than normal, plant growth may have slowed)

For many Labor Day weekend is considered the unofficial end of summer. For the ag community in Northeast Illinois the end of summer is the Sandwich Fair, held annually the week following Labor Day. Yesterday I had the opportunity to judge commercial corn entries at the Horticulture and Crops barn at the fair, Using the size and kernel number of ears as an indicator, it has been a good growing season. In the field, both corn and soy are nearing maturity, in most fields I observed it appears corn is winning the race. Most in this region will likely start the 2026 harvest in corn before soy. As farmers prepare for the harvest this is an ideal time to check corn fields for any standability issues. This can be accomplished by walking the field or by use of a drone. With this knowledge, field harvest order can be adjusted accordingly. With the variability we have seen within fields this year it will be important to check combine settings often during crop harvest.

Talon Becker – Commercial Agriculture Specialist

Champaign County

Soil Conditions:Mildly Dry (soil is drier than normal, plant growth may have slowed)

Harvest has begun in northern Champaign County, albeit on very limited acreage, primarily seed corn fields at this point. Another week of dry weather along with high temps in the 90s have dried up any standing water that remained in fields in that part of the county and has moved the corn crop, in particular, much closer to harvest. Most corn fields I visited still have not quite hit full physiological maturity (R6), but with the milk line all but disappeared on most ears, they don’t have far to go. Ear size and grain fill was once again variable. Foliar diseases in corn are “helping” to turn fields from green to brown quickly at this time of year, and I’ve seen a bit more lodging in corn fields as the weeks progress. In fields surveyed with lodging issues, the main culprit appeared to be Diplodia stalk rot. But other stalk and crown rots could be contributing to this issue as well. I’ll reiterate my message from last week encouraging the use of recent drone or satellite imagery to asses lodging severity in fields to aid in harvest decision making. Soybeans are also progressing towards maturity, but many fields remain with plenty of green in the canopy, still somewhere between full seed (R6) and beginning maturity (R7) growth stages.

Dane Hunter – Commercial Agricultural Specialist

Marion County

Soil Conditions: Moderately Dry (soil is dry, plants may be browning or stressed, water bodies are low)

I haven’t made a report for several weeks as I’ve been on paternity leave and up to my elbows in diapers and bottles for my twin infants. Until this last week my windshield surveys had me thinking that the crop was still doing pretty well despite the hot dry weather over the last two months. I had seen a few patches of stressed plants in pockets of fields with thinner soils, or regions that missed a rain, but overall, the crop didn’t seem too visibly stressed. In the last week (prior to the rains that came through on 9/10/26) I started noticing more and larger areas of visible stress. When I walked out in some late planted and double crop beans that from the road, looked healthy; I was surprised at how many pods contain only one or two developing beans. Clearly the hot dry weather was impacting fertilization and seed set more than I realized. A lot of these later planted fields do have a number of very small pods that may still set. Hopefully the rains this week help prevent them from aborting and at least fill the pods we do have out there.

I saw my first combine shelling corn in Marion County on August 27th. I still have only seen that one farm shelling and drying corn, everyone else seems to be letting the triple index heat dry their corn down for now. The hot, dry weather has had all corn in the area at black layer and drying for a while, regardless of how late it was planted. From what I’ve seen, it looks like corn planted from April to mid-May had decent fill before being forced into senescence. Ear size may not be anything to write home about, but it seems there’s more grain out there than 2025 in this area (which is a low bar). Fingers crossed as combines start to get rolling.