We have had a bit of a mini heat wave here in the middle of September, as temperatures returned to near normal compared to the previous two weeks of cooler weather. The warmer temperatures are helping the corn and soybeans progress through maturity, as we are a bit behind the rest of the state, harvest- and maturity-wise. As the rest of the state enters more substantial droughts, areas north of I-80 are still within normal rainfall, with a small pocket near Evanston entering another early drought phase. With little rain in the forecast, I don’t expect many delays with dry down and senescence. Some windy days would help greatly as well.

Disease has emerged in fields due to the cooler temperatures and heavy dews in prior weeks. Tar spot in corn is the main concern, which will build inoculum for future seasons in fields with hot spots, as well as SDS and Cercospora in soybeans. The SDS has done most of the damage it will do, but Cercospora can lead to purple seed stain and dockage at the elevator, so that will be a disease to monitor throughout harvest.

Corn is firing up through the fields, but there is still a lot of green out there. The furthest progressed fields I saw in DeKalb were just reaching black layer, with other fields still at the 60–75% milk line. This warmer, dry climate will help the plants start to dry down in the next couple of weeks. West and south of DeKalb are well ahead maturity-wise, and harvest will be here in a matter of weeks. Corn has strong stands, and I have not seen much, if any, lodging across the region outside of small pockets that had hail damage early in the season.

Soybeans are turning and senescing rapidly. The late start to the season, with cooler temperatures, has prolonged maturity compared to other areas of northern Illinois. Cercospora is the main disease I have seen while scouting, with a small amount of frogeye leaf spot. Beans are still very wet, and very few fields have reached near-complete defoliation. Another week and a half should bring defoliation close to completion.

On a lighter note, apple orchards and pumpkin patches are in full swing, and plenty of fall festivals are on the horizon to enjoy this great weather across northern Illinois.

Harvest is underway in southern Vermilion County. With the hot, dry weather we’ve had, most farmers seem to be focusing on soybeans, likely in hopes of minimizing shatter and header losses. I did see a number of cornfields harvested, but those were mostly seed corn fields and only a couple of production fields. Of the corn still standing, the majority is at R6, or “black layer,” but with some green remaining in the leaves of the upper canopy. I did find a couple of fields still in early R5, or “dent,” yet to reach maturity, but those were few and far between.

As has been the story for much of the region, ear size and tip fill have been relatively variable field to field, with some showing full ears and others an inch or more of bare cob. Soybean fields still standing were generally in the R7, or “beginning maturity,” to R8, or “full maturity,” stages, with a few stragglers still in late R6, or “full seed.”

West-Central Illinois Field Report

The past month and a half has been an interesting one.

Just before August, expectations for overall corn and soybean yield ran high—only to be dashed by a rather dry and exceptionally hot several-week period.

The crop rapidly went from feeling like it was cruising toward excellence to seeming as though it just wanted 2025 to be “over and done with.”

Recent soybean conversations have emphasized the lack of four-bean pods and a proliferation of two-bean pods—an unsettling observation that has increased fear beans will miss the mark for ’25.

Corn acres had a very similar look and feel for much of the past month, with a growing sentiment that warm nights shaved the top end off.

The earliest planted, shorter-maturity fields have begun to come off, with a few observations hinting at a likely overall theme.

First, in corn, this was a fungicide-response year. Twenty- to thirty-bushel yield benefits from applied foliar fungicide (versus no fungicide) are already being reported.

Second, southern rust will be a big story going into the winter of ’25/’26. Not only was it a major foliar disease in west-central Illinois, it also pushed north in stunning ways. Growers as far north as Madison, WI, will suffer rust yield losses this season. The experience strongly indicates that, more seasons than not, corn will be plagued by some kind of foliar fungal disease.

Third, soybean moistures are already hitting the single digits in some areas. This will cost weight—and slash income—at the elevator, but it also hints at another year of industry-wide seed quality issues. Soybean coats become too delicate at such moisture levels.

Finally, the 2025 season made for a very unusual Red Crown Rot story. Symptom development in historically RCR-prone areas was delayed and/or less extensive. New areas to the east of major RCR epicenters were much more problematic. Researchers and agronomists will spend much of the winter speculating why RCR played out the way it did.

Harvest has officially begun in Logan County, with some corn fields being harvested earlier this week. A lack of significant rainfall, combined with the high daily temperatures over the last couple of days, has pushed plants toward harvest. Some corn and soybean fields are still too green, so it remains to be seen how the forecasted high temperatures over the weekend will impact their readiness.

All of my three-county area is in some form of drought, with part of it in “D2, Severe Drought.” Crops are maturing rapidly. Due to environmental stress and drought, corn is showing top die-back and firing leaves up to or near the ear. Soybean fields are quickly maturing, with the upper node or nodes of pods having two seeds instead of three.

With only about an inch of rain over the past 30 days from a single event, the crop is drying down quickly in Northern Champaign County. Corn fields surveyed were generally at R6, or “black layer,” but are still a little way from harvestable. Most fields are still showing green leaf tissue above the ear leaf, but senescence will likely progress quickly with warmer weather in the forecast and minimal chances for rain at this time. Harvest operations were taking place in a couple of seed corn fields I drove by, but I didn’t see any combines rolling in production fields quite yet. Some soybean fields are at R8, or “full maturity,” and will likely be ready for harvest any day now, while others are still in the late R6, or “full seed,” stage—still green throughout much of the canopy. The couple of double-crop soybean fields I visited were at R5, or “beginning seed,” but may struggle to fill pods with the lack of available soil moisture.

Harvest is on the horizon, and maturity and dry down will likely be expedited with the return of forecasted warmer temperatures. Looking back 150–170 days and evaluating the current growing season, most crop stressors were environmental (dry or drought conditions) or related to plant disease (primarily in the corn crop). Recent field surveys suggest higher yields in fields that received isolated or intermittent rainfall or had soils with greater water-holding capacity. Soon, combines will be rolling, and the true impact of the growing season’s challenges will be known. We encourage everyone to prepare for a safe harvest season.

Harvest has begun, and very dry conditions are moving back in. Fire risk is becoming an issue as harvest picks up speed. Late-planted corn is in real trouble, and all crops are ripening fast.

Over the past few weeks, weather conditions have been fairly dry—so much so that many were hopeful for a shower or two to help finish grain fill. Thankfully, our territory caught a few nice rains, ranging from ¼ inch to 1 inch. Temperatures went from unbearably hot to super comfortable and fall-like, which has been a blessing after a long, abnormally warm spell.

In my opinion, as I’ve revisited corn fields after pollination, the ears have filled very nicely, leaving me anxious for harvest to begin. Last week, most of our cattle producers who chop silage put theirs up. A few growers have also started harvesting their early-maturing varieties, like 106–108-day corn, with moistures as low as 24–25%. Many of the hand-shelled moisture tests I’ve taken have been in the 28–36% range, so we may be a week or so away from broader harvest. I anticipate many more starting next week for sure.

As for soybeans, they are starting to change—and seem to change by the day. Early last week, we flew on the majority of our cover crop mixes that will be used for grazing this fall and into the spring. More planes will be rolling tomorrow, spreading rye and radish mixes over corn going to soybeans.

Onward! Corn and soybeans both are marching toward season’s end. Fields in my area are really starting to have that “late-season” look this week. Much cooler temperatures arrived on 9/3, and daytime highs in the mid-60s really made it feel like fall. Walking through corn, I’ve noticed a significant uptick in foliar disease across the board. Some fields are showing quite a bit of GLS, and others NCLB, on and above the ear. Most notable to me, however, was the amount of late tar spot I’ve seen. Natural leaf firing from the bottom is a normal part of filling out the ear, but there’s a difference between that and earlier-than-normal leaf death from the culmination of tar spot plus two to three other leaf diseases. I’ve been in some fields that really need to be watched closely as harvest approaches, and I hope they don’t get a significant wind event. Stalks in the worst fields are already weak and prone to breaking just by crossing rows. Most ears look good and are well into dent stage, with milk lines ranging from ¼ to ¾. I expect black layer to be a couple of weeks away yet in most fields.

Soybeans are mostly into the full seed stage, and you can see the leaves beginning to yellow. Early-maturity fields are into leaf drop now, and some are probably 50–60% dropped. Pockets of Sudden Death Syndrome are beginning to show up a little more, but it does not appear to be as widespread as in some years. I have not seen any red crown rot in my area. Cooler overnight temperatures have led to some very heavy dews in the mornings. Lingering moisture on green leaves, plus a blue sky and sunshine, has caused a fair amount of sunscald on the bean leaves, but at this point I would not expect that to have any significant impact on the plant.