Depending on location, we have received between 1.5 and 4 inches of rain in the last week. It had previously been very dry in some areas, while others were lucky enough to get some pop-up showers. We now have the conditions for diseases to start showing up in corn or soybeans, but this will also depend on their disease susceptibility or disease scores. A few Northern corn leaf blight lesions were present in corn, but I was more concerned with the spread of gray leaf spot from the lower leaves. Japanese beetle infestations have ramped up, especially in later-planted soybeans. If farmers have decided to make fungicide/insecticide applications, they will start on corn this week as it has reached the VT growth stage. Early-planted soybeans have canopied and will soon reach the R3 growth stage. If warranted, they will also receive fungicide/insecticide applications at R3.

In Franklin County this week, I found a couple of soybean fields in full flowering (R2), despite being shin-knee high. Beans in this area vaulted straight into flowering at only V5–V6, since days have started shortening after the solstice. Most double-crop beans are in the ground and at VE–VC.

On the corn side, I have seen one field tasseling — it must have been an atypical field that got planted in April. Most corn fields are still vegetative (V9–V10), with no sign of tassels yet.

The growing season is entering a key phase, during which many fields and plants are transitioning into the reproductive stage of growth. Nearly all of the corn fields in the area have entered the R1 phase, with some likely further along. There are still some fields in the later V-stages, but they won’t be behind the rest for too long. Much the same story can be said of soybeans, with some more mature fields in the R1–R2 phase, while others are in the later V-stages. Rainfall has also been variable across the area over the last week. Some parts of the county received around an inch of rain, while others received a half-inch or less.

More hit-and-miss rainfall last week in NE Illinois as additional corn acres begin to reach VT (tassel). Areas that received rainfall are faring considerably better than those that did not. Corn growing in fields with gravelly knolls and lighter or sandy soils that did not receive recent rains is showing significant stress. Fungicide applications have started in the area. In scouting visits to R1 corn fields, the only disease noted was sporadic Northern corn leaf blight. This disease is recognizable by the cigar- or canoe-shaped lesions formed on leaf tissue. The causal pathogen for this fungal disease overwinters on corn leaf debris. Hybrid resistance is normally adequate for management of the disease, but substantial losses can occur with early infection and susceptible hybrids.

Interesting, but normally not economically important, leaf feeding was also noted in the corn. The corn blotch leaf miner is a small fly that deposits eggs on either the upper or lower corn leaf surface. After hatching, the larva tunnels in the leaf, feeding on the inner leaf tissue as it grows, leaving behind mines or transparent galleries. Eventually, the larva chews its way out of the leaf, drops to the soil, and pupates. I’m finding very limited leaf feeding, despite the presence of Japanese beetles, and no diseases at this point in the growing season in the soybean fields visited.

Currently, the corn and soybean crops are looking good. Some corn in the drier areas has fired on the lower leaves.

Soybeans vary from V5 to R3 (beginning pod), and corn varies from V10 to R2 (blister), with most of the corn crop in the R1 stage. Weed control is generally looking good; however, the amaranths are beginning to poke above the soybean canopy in some soybean fields.

Rainfall over the past 14 days has been over 150% of normal in southern Macon and Piatt counties, and less than 25% of normal through the balance of the three-county area.

Now is the time to begin monitoring corn rootworm beetles — both to evaluate the performance of traits/insecticides used this year and to gauge the need for control next year. We will again be distributing yellow sticky traps to anyone interested in participating in our regional corn rootworm adult monitoring network in 2025 (for more information about the network and to see reports from previous years, visit www.rootwormipm.org).

If you are interested in participating and would like me to send you traps and/or the sampling protocol, please send me an email (nseiter@illinois.edu) with the following information:

• Your name and shipping address
• The number of corn and soybean fields you plan to monitor

Central/West-Central Illinois Report (7/9/25)

About 40-45% of the soybean crop seems to be setting up very well for yield. Color, canopy closure, and general appearance look very good in those fields. The “mid-season vibe” for that portion of the crop is good, but “the final story” is yet to be told. Growers are holding their collective breath for late July/ early August rainfall that would set that story in concrete.

Don’t discount the crop that sits just a shade lower in general appearance (about 40%). That portion also is set up well, but the finish line is still very far ahead.

All of that said, there are some fields that had begun to struggle previous to this week’s rainfall. About 15-18% of fields have not yet closed canopy, generate concern for those fields in the countryside. About 3-5% of fields were doing that because droughty stress had reached severe levels. In those locations low organic matter ribbons of soil were evident with beans graying off, occasionally yellowing up, and – in the worst cases browning. Rainfall totals ranging from a tenth to a few inches alleviated that stress early in the week.

Roughly 65-75% of the corn crop has tasseled. Those fields that have not yet tasseled will do so in 3 to 12 days with an average of about 6 days to tassel (across the geography). As with beans, about 3% of the crop had shown evidence of severe droughty stress previous to rain. Moisture stress induced edge of field potash deficiency is evident in about 6% of fields.

Another dry week for northern IL, with a few isolated storms occurring farther west or in Chicago. We have slid back into a predominantly D1 drought, with large areas of Kane and Will counties entering into a D2 drought. Corn and soybeans have started to grow out of the early-season stunting, but both crops are likely to be short overall this season. Temperatures dropped a little bit this past week but were still in the mid to upper 80s. Depending on planting date, corn is between 1,200–1,250 growing degree units as we continue to progress through the season.

Corn is averaging V11–V13 across the region. Some isolated fields are still lagging quite a bit behind, around V8–V9, but an overwhelming majority are spiking. Ears are starting to develop, and a small handful of fields have tassels emerging. I expect that by next week most fields will have tasseling corn. Disease is still incredibly low for this time of year; I have not found tar spot in any fields that I have scouted — let alone gray or northern blight. Many areas south of the I-80 corridor have confirmed cases, with the only county north being Carroll County out west. I continue to encourage regular scouting of your fields to stay on top of diseases. I have not seen any insect pests, but fall armyworm damage has been reported in sweet corn, so that is something to monitor.

Soybeans are beginning to enter R3 as pods are developing on the lowest nodes. Plants are healthy and beginning to fully shade out the rows. I have not seen any diseases yet, due mostly to the weather. Japanese beetles are present in most fields, but numbers aren’t anything to be concerned about currently. I have seen quite a bit of herbicide residual burn on beans this season, and it’s unclear whether the hot and dry weather is the culprit or different chemical mixes. Either way, the beans are growing out of it.

If you see any disease, insect damage, or anything else of note as the season continues, please feel free to email me images with descriptions at sbbrand2@illinois.edu.

With about 0.5–1.0″ of rain and some cooler temperatures, this past week, corn and soybean crops in Douglas County are looking healthy during this vital flowering period. Most soybean fields are somewhere between the full flowering (R2) and beginning pod (R3) stages, with a few fields moving into full pod (R4). At least 50% of the corn fields I saw during my survey had started to flower. Most of those fields were still in the early stages of silking and anthesis (R1), but a couple of fields I visited were entering the blister stage (R2).

Wheat fields I drove by had all been harvested. Many had been planted to double-crop soybeans sometime last week before the rain, and I saw a couple of farmers getting ready to roll again as soils dried enough to allow for field traffic. In the southwest part of the county, several alfalfa fields had their second cutting, with one or two still standing. Oat fields looked to be a week or so away from harvest.

Scattered rain for the next several days. The crop is finally taking off. Corn growth stages are from emerging to Brown silk. Crazy spring!