Diseases should continue to be monitored for progression. The temperatures next week will most likely slow tar spot advancement. Note weed escapes to determine if adjustments need to be made for 2025. The hope for next week is maturing crops and not premature death.

We really could use a rain for the later planted soybeans as well as some corn. Despite the dryness, some tar spot and southern rust has started to show up on late-planted corn. European corn borer was also found in late planted corn (R3). Overall, soybeans are progressing well, but have unfortunately found red crown rot as well as SDS. Frogeye leafspot is just starting to show up.

It’s a good time to scout for fall armyworms in grass hay, pasture, alfalfa, etc; a quick survey of my colleagues in the states to our south indicated it is a big year for this insect (though they were unanimous that it was not as bad as in 2021, the last time we saw widespread damage in Illinois).

Crop conditions continue to look good around Logan, Menard, and Sangamon counties. While there has not been much rain in the last week, cooler temperatures have ensured plants are not under heat stress as we approach maturity. There have not been any significant reports of any diseases across the area, though some isolated cases may be present. Many local producers have also completed their third hay cutting for the year. With the cooler temperatures and rain over the last couple of weeks, many fields are already starting to grow back nicely and could see a fourth cutting.

Recent precipitation and current cool conditions are favorable for both corn and soy crop grain fill. The extended forecast is dry and warmer, which could expedite the grain fill window. For crops on some lighter soils in the Northeast, recent rains appear to have arrived late. Corn in sandy and soils with poor water holding capacity senesced quickly over the recent week. In field areas that flooded or have decreased plant populations due to environmental conditions, I’m finding grass weeds happily filling the void. One species in particular, Fall panicum, seems to be having an exceptional year. This summer annual can reach seven feet in height and is recognized by appearing to be growing in a zig-zag pattern caused by growth bending at the nodes. The seedhead is easily identifiable, resulting in a wide spreading panicle when mature.
For those in Grundy County and surrounding areas, Illinois Extension and the Kendall-Grundy Farm Bureau are partnering to host University of Illinois plant pathologist Dr. Boris Camiletti on Wednesday, August 28th at 1:30 pm at the Kendall-Grundy Farm Bureau building. Dr. Camiletti will lead a discussion on his research projects and share experiences in his first Illinois growing season. Producers, landowners and agronomists are encouraged to bring plant samples the afternoon of the meeting for discussion or identification purposes. Anyone is welcome to attend, the Kendall-Grundy Farm Bureau building is located at 4000 N. Division street in Morris, Illinois.

Following the storms that came through the areas late last week, soils have plenty of moisture in the northern Vermilion County area. There was standing water visible in some small ponds in headlands, but these were few and far between. Crop health looked good, overall, but corn fields are starting to show some areas with late-season nitrogen stress with variable ear size and tip fill. Signs of what appears to be Physoderma stalk rot (visual identification only) were also present in a number of corn fields (https://cropprotectionnetwork.org/encyclopedia/physoderma-stalk-rot-of-corn). In fields surveyed, corn was at late R4 (dough) to early R5 (dent). Soybeans generally ranged from R4 (full pod) to R5 (beginning seed), with a few fields edging closer to R6 (full seed). Weed control was variable. Most corn fields I walked into were relatively clean, but soybean fields showed a range of weed control efficacy.

Cool temperatures lately should help grain fill. Moisture in CIL has been plentiful. Disease is starting to show especially what appears to be SDS in soybeans. I have seen several diseases in corn, but so far nothing of major concern. Tar Spot could be one to watch as it can rapidly evolve. I have heard of some 2nd fungicides being applied to the later planted corn to help it finish. The low areas of fields are starting to show up again, likely due to leached N or compaction and thus lacking root development.

Crop growth remains much the same as last week. There were some pop-up showers on Monday, but these did not bring much in the way of total precipitation. Storms are in the forecast for tonight, so hopefully, there will be enough rainfall to replenish topsoil moisture. Much of the corn crop remains in the R4 to R5 stages, with the later planted corn in the R3 stage. Most of the soybeans in the area have fully developed pods, with some beginning to form seeds inside the pod.

Rain is in the forecast which would greatly benefit the soy crop in drier areas of Northeast Illinois, that crop is still at R5 or beginning seed. As we reach mid R5 we can expect the remobilization of nutrients from leaves and stems to start. While few reports of soy disease have been noted to date, a report of White Mold in Kane County was shared this week. Most corn fields visited are now at some stage of R5 or dent stage. In lighter soils lacking rain, significant firing is evident. As our crops near maturity many farmers have turned their attention to readying combines and other harvest equipment. While important, we can also find value in late season scouting visits. This week has been a very interesting in corn leaf diseases, Tar Spot continues to infect and spread within and across fields. This is the time to evaluate fungicide application efficacy or hybrids inherent or bred tolerance to Tar Spot and other diseases. In addition to Tar Spot, symptoms of Northern Corn Leaf Blight, Gray Leaf Spot and Southern Rust can be found in area corn fields. Visiting fields with disappointing weed control can also provide insight into management decisions in future years. Included is an image of Waterhemp treated with a tank mix of Enlist and Liberty that killed the apical meristem but not the plant. In visiting Dr. Aaron Hager, Weed Specialist at the University of Illinois, he shared the current message for Waterhemp control in soy. I had to chuckle (and could relate) at recommendation 7.
1) Use glufosinate with Enlist One instead of glyphosate. If we miss grass with the tankmix, we can always come back and clean it up with glyphosate. We do NOT want to miss the waterhemp with the first application.
2) Keep the water volume close to 20 gpa whenever possible.
3) Be sure to use the correct spray tips; these drift reduction nozzles are terrible for contact herbicides, such as glufosinate.
4) Spray small waterhemp. If the field average size is 4 inches, the reality is a field with plants ranging from 8 inches to ½ inch.
5) Keep the AMS at the label recommended rate. This is NOT the place to cut costs.
6) Glufosinate likes bright sunshine, high air temperatures, and high humidity. Applications made when one or more of these are missing often are somewhat compromised.
7) Spray glufosinate like you once sprayed Basagran (that one resonates only with those with at least a touch of gray hair).

Corn is in the dough to dent stage and generally looking good. Fields that have experienced hail after the ear formed are showing ear rots. Corn leaves tattered in every field across the area. No tar spot evident, yet.
Full season Soybean are in the R4-R5 stages and plant health is good. Double crop soybeans are in bloom with small pods forming at the lower nodes.