It’s a challenge to report on soil conditions in northeast Illinois due to isolated pop-up thunderstorms. Some fields received over an inch of rain, while many less fortunate areas are drying quickly under above-average temperatures. I’ve noted many soybean fields exhibiting significant leaf burn from post-herbicide applications—likely a result of tank mix chemistries, additives, and environmental conditions. As our day lengths shorten, we’re reminded that soybeans in our region have an indeterminate growth habit, meaning vegetative growth (additional leaves) continues even after reproductive growth (flowering) begins. Despite high temperatures and limited rainfall, most corn fields visited still have wet leaves early in the morning. Periods of leaf wetness and high relative humidity are key risk factors for several corn leaf diseases, including Tar spot and Gray leaf spot.

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.

Currently, the corn and soybean crops are looking good. Soybeans range from V3 to R2 (full bloom), while corn varies from V7 to R1 (silking), with most of the crop at V10+ and some expected to reach VT before July 4. Weed control is generally looking good. Alfalfa fields are ready for the second cutting.

Crops are off like a rocket in our territory. Favorable growing conditions—warm weather and timely rains—have set us up for success. With these conditions, concerns about crop diseases like the dreaded tar spot are becoming a reality. There have been several sightings of it in our territory. If the heat continues as it has this week, we believe it will help reduce the push of infection.

As for soybeans, many post applications have been applied. These treatments continue to show significant crop response on the leaves. We’re also seeing good success with these applications in controlling waterhemp and other tough-to-kill pests.

It’s that time of year when we encourage producers to take a two-week vacation—and come back to clean fields and beautiful crops! Corn is coming out of its ugly stage as it finds nitrogen, and soybeans are rebounding nicely after the initial setback from post applications. All in all, we’re excited about the potential our crops continue to show.

After a very hot and humid week, LaSalle County received some much-needed rainfall on Tuesday night. Crops were exhibiting considerable heat stress before this, but overall, they’re now looking much healthier. Additional rainfall is in the forecast for Wednesday night and potentially into the weekend, though temperatures will remain in the high 80s to 90s. Corn is reaching V6–V7, and most soybeans are at V2–V3. There is a wider range of growth stages among soybean fields, with some recently replanted; one scouted field was already at R1. No significant pest or disease issues have been observed yet, although Japanese beetles were present in many soybean fields. Recent reports confirmed Tar spot in Bureau County, so growers should stay vigilant and continue scouting.

The high temperatures over the last week have caused many corn fields to grow at a rapid pace. There is hardly a corn field that isn’t knee-high—one week before the Fourth of July. At the University Research Plot in Hartsburg, IL, corn is at the V9–V10 stage, with other fields in the area at V7–V8. Soybeans have faced a tougher challenge with the high temps. While some fields are handling the heat well, many are showing signs of stress, including cupped leaves. There are no additional signs of insect or disease pressure yet, but continued high temperatures will likely lead to more issues.

The heat this week has certainly helped move the crop along in Champaign County. And despite a couple of pop-up showers, it has also helped dry out fields enough for post-emergence herbicide applications, which were needed—and probably a couple of weeks past due—in several soybean fields. Soybeans with good early-season weed control remain relatively clean. Many soybean fields are starting to flower (R1) or have reached full flower (R2), but there are still plenty of later-planted fields in earlier vegetative growth stages (V2–V3).

Early corn is about head high, around V14–V15. Brace roots are just starting to emerge in these fields, which will help in some cases where plants are still leaning from last week’s strong windstorm. Later corn is generally in the V6–V8 range and starting to grow more rapidly. I passed one wheat field already harvested during my survey and a few others that were fully mature (Feekes 11.4) and not far from harvest themselves.

Although the heat and break from the rain were needed for many farmers to wrap up early-season field operations, conditions could quickly tip toward the dry side with rapidly growing (and transpiring) crops. As always, timely rains will be critical to replenish soil moisture and minimize stress during these hot summer days.

Central/West-Central Illinois Crop Report 6/23/25

A drive through WC/C IL late last week showed a sizable fraction of the soybean crop still fighting to get past the “early-season” uglies—the typical yellow-green look we see every year. That story began to shift over the weekend as heat drove further root development, turning the countryside (in many places) a more satisfying dark green.

As we would expect, given variable planting dates, crop development remains diverse. The bean crop currently averages 6 to 7 nodes, with the earliest-planted fields showing 10 to 11 nodes and the latest-planted showing 3 to 4. Rows in many areas have begun to canopy, and our first batch of flowers can now be observed in several locations.

Weed control has been a recent point of discussion. Some of those conversations have included concerns about damaging the first flush of flowers, particularly where weed pressure has been more difficult to manage.

The southeastern portion of this area is experiencing what Southern Illinoisans know too well—the rain never wanted to shut off, and now it seems to have disappeared.

Japanese beetle emergence began last week, and grape colaspis adults will soon follow.

In other row crop news, tassels began emerging in our earliest-planted corn fields over the weekend. Most of the corn crop is still several leaves away from the reproductive stage, but kernel establishment is approaching quickly.

Wheat harvest will soon knock on the door, and hay bales are beginning to dot fields across the area.

Recent precipitation in Northeast Illinois ranged from 1+ to over 4 inches of accumulated rainfall. Some edge-of-field wind damage was noted in corn fields. The earliest planted soybeans are starting to flower, entering the reproductive stage of the crop. The most mature corn has reached, or is near, V10 to V11.

A reminder: if scouting mature corn, lower leaves will start to drop. In these cases, the first measurable internodal space is generally between the 5th and 6th node. Recognizing this provides a starting point at V6 when staging older corn. Depending on corn hybrids, expect between 15 to 20 leaves prior to tassel emergence. This is an important period of rapid growth as the corn plant creates leaves and stalks to provide photosynthate for the ear and developing kernels.

I’m a strong advocate of spending time on the ground scouting fields and recognizing any manageable issues that may arise. That said, I can also appreciate drone imagery for providing different perspectives on the developing crop. I have had mixed experiences with drones, but I have to admit the newer generation is more user-friendly. For those with access, collecting aerial images as the soy and corn crops transition from vegetative to reproductive stages can provide insight during end-of-season crop evaluations.

Earlier this week, I had the opportunity to visit a field with probably the worst grape colaspis injury I have seen. Note the phosphorus deficiency symptoms on the lower leaves of many plants and the aggregated nature of the injured plants. Usually, we see this in fairly isolated areas of a field—often at the high points—and several nearby fields had this more limited injury. But in this particular case, much of the field was affected. When you see this kind of injury above ground, dig up the plant and look for larvae, which resemble tiny white grubs. Some plants in this field had as many as eight or nine larvae on them, and we found at least one pupa. These should cycle out into adulthood soon.