Another week of varied precipitation in northeast Illinois, but mostly favorable growing conditions. Corn has reached R3 (milk stage). At this stage the moisture of the kernel is about 80%. Leaf disease incidence continues to be low in corn and soy fields visited. Most soy is R3 to R4, beginning to full pod. In addition to the crops entering their reproductive stages, so too are some weeds, including waterhemp. This weed is dioecious, both male and female plants having flowering structures. Once mature, the plants can be easily sexed by the presence or lack of shiny black seeds.
This week I attended the Monmouth Research Center Agronomy Day and was able to gain insight explaining why many were seeing waterhemp uncontrolled by post herbicide applications. The surviving plants appeared weeks after the post herbicide application as bushier, more robust plants. University of Illinois ‘s Caleb Wepprecht discussed “HPPD Resistant Waterhemp- A Growing Concern” and shared his take on weed control challenges from this year. A few factors in waterhemp escapes were inadequate spray volume on larger plants, leading to inadequate coverage of the growing points, even with systemic herbicides, as well as low use rates/dosage of herbicide in the weed itself, along with the concept of metabolic herbicide resistance, leading to the waterhemp’s survival and altered plant structure. As farmers see waterhemp escapes in fields, Caleb encouraged attendees to take whatever steps possible to prevent the prolific seed-producing weed from maturing and causing future concerns

An active week on the weather front in Northeast Illinois. Several storms packing high winds roared through the area. Despite this, to date, I have heard few reports of down corn. Regional corn fields are at varied maturities because of planting dates. The earliest planted has reached R2 (Blister), the developing kernels appear as clear fluid containing whitish blisters on the cob, silks are brown and drying rapidly. Most soy is also at R2 (full bloom) and closing canopies in 30″ rows. Fungicide applications are underway by plane, helicopter and drone (and likely ground rigs when field conditions permit). I noted isolated incidence of Gray Leaf Spot and Tar Spot this week, I plan on revisiting those corn fields within the week to reassess. On some corn plants lower leaves exhibit the inverted V symptoms of nitrogen deficiency. Leaf senescence occurs naturally and is identified by corn leaves losing greenness due to a reduction in chlorophyll. Not all nutrients are lost, some assimilates are “remobilized” and transferred to the ear and kernels so that grain fill can be sustained and completed. While a natural process, lower leaf senescence and its counterpart, top dieback, can also be initiated by crop stresses and bears watching in future field visits.

The remnants of Hurricane Beryl passed through northeastern Illinois depositing widespread and varying precipitation. Area wheat growers who have yet to harvest are facing an extended combining schedule and likely lower test weights as the grain rewets and dries. Many corn fields are currently pollinating, always an uncomfortable time to scout. Even so, it is still a critical time to do so, determining leaf disease pressure and fungicide application decisions. Current commodity prices suggest an eight to ten bushel preservation of yield is necessary to justify the cost of most aerial applications. I have yet to see Tar spot, but an agronomist further southeast shared that symptoms have been found. The University of Illinois Plant Clinic is offering free Tar Spot screening again this year. The downloadable screening form can be found at https://extension.illinois.edu/sites/default/files/2024-06/2024_free_corn_tar_spot_form_0.pdf . Waterhemp is starting to push through soy canopies and many conversations in July have centered on resprays and herbicide dissatisfaction. Make note and evaluate your level of control in fields as you plan for 2025. I always enjoy seeing brace root emergence in a corn field. I note hybrid differences and have heard a plant breeder suggest that brace roots are a photosynthetic drain on a corn plant yield potential. Whether it helps or hinders final yield, I feel better when seeing corn plants with the additional anchoring support of brace roots that make it to the soil. In my mind, it’s going to help that plant stand through harvest.

This past week I had the opportunity to travel a larger area of northern Illinois. Generally, both corn and soybean crops appear to be in good shape. This comes as somewhat of a surprise when considering what the crop has endured to this point (near midway) in the growing season. Earliest planted crops include R1 corn and R2 soy. In recent trips across the countryside, I see acres of soy and often come across a field that from a windshield survey appears to be suffering from dicamba drift, so much so that I stop and visit the field. I recognize that we are far removed from the June 12th application deadline of Soy dicamba chemistry and most post corn applications. Yet the HG 4 (growth regulator) symptoms are showing up on new trifoliate leaves in many northern Illinois fields. Some fields I know, and most I expect, are Enlist beans. Why are we still getting the wrinkling and white tipped leaves? This may turn into an insect year, while scouting this week my checklist included Western corn rootworm beetles, Northern corn rootworm beetles, Bean leaf beetles, Japanese beetles, Potato leafhoppers and Grasshopper nymphs.

A shift in the 2024 growing season, we have transitioned from fields experiencing levels of wet, saturated and underwater to having some version of hot, dry and stressed crops in many areas of northeast Illinois. Many soy fields have received their post herbicide and are slowly putting out new trifoliates because of unfavorable growing conditions. Uneven corn fields can be found in areas most effected by heavy rainfall events earlier in the season. Earliest planted corn has reached V11 to V12 growth stage. While scouting (a job best done early morning with current temperatures) I noted fungal growth developing near whorls and on corn leaves. My prognosis is an early season infection of Corn smut, to be confirmed by the University of Illinois Plant clinic. In the fields visited the infection appears to have a varietal influence.
For those in northern Illinois I always encourage farmers to be aware of what is happening downstate to alert us to potential issues we may encounter later. Looking at information from neighboring states is beneficial as well, and recently both Iowa and Indiana confirmed the presence of Tar spot. In both states it is considered one of the earlier dates for confirmation of the disease. The annual spread of the disease can be followed on the Corn ipmPIPE. https://corn.ipmpipe.org/tarspot/
Be on the lookout and be safe when working in the hot weather!

Sunshine and warmer weather are accelerating crop and weed growth. Because of varied planting and replanting dates, both corn and soy post herbicide applications are underway. Largest corn is V9 – V10 stage, soy is V4 to V5 and nearly R1 (beginning bloom, one open flower at any node on the main stem). We are getting flowers on soy over a week before summer solstice! Despite what some of us learned about the connection between the longest day of the year and flowering, this phenomenon is becoming more frequent with earlier plantings. Photoperiod sensitive soybeans are considered a short-day plant. Despite the inference, flower induction is triggered with a longer night length. The soy plant’s ability to measure night length starts early, when the unifoliate leaflets are present and a young trifoliate can be detected at the second node. Dependent upon the soybean variety and maturity, once that plants critical night length is reached, flowering is initiated, before or after June 21st.
With our Dicamba products for Xtend technology soy reaching their June 12th application cutoff in Illinois, we should also look at label recommendations for Enlist products. The Enlist One label specifies for post applications applied to Enlist traited soy, ” Apply when weeds are no larger than 6 inches and any time after soybean emergence through the R1 growth stage.” As always, take the time to read and follow label directions before mixing and applying pesticides.

A good growing week in NE Illinois for most. Some precipitation and several rain free days with sunshine. The earliest planted corn is V7 to V8 and earlier planted soybean is V3 to V4. Now that most planters are parked, other activities are underway. They include sidedressing nitrogen, post herbicide applications on corn, and harvesting the first cutting of hay. Several days after corn post herbicide applications have taken place, scout fields to evaluate the performance of your post herbicide application. Be wary of hard to control weeds such as Marestail, with populations resistant to glyphosate in Illinois and a challenge to other chemistries once they bolt and reach a height of 6 – 8 inches. To learn about the newest in weed management plan on attending the University of Illinois 2024 Weed Science Field Research Tour on June 26th. The tour takes place at the Department of Crop Sciences field research location known as the Clem Farm, located at 1114 County Road 1200 East, Champaign. Registration begins at 8:00 a.m. and the tour will start at 9:00 a.m.

A dryer weather pattern allowed most to finish or nearly finish planting or replanting. Earliest planted corn is near or at V6 and earlier planted soy is now V3. We encourage early scouting of fields, including replant areas to evaluate crop emergence (note soy replant seedling feeding in picture), weed pressure and height. Expecting post corn herbicide applications to start soon.

Drying out this week in Northeast Illinois, planters are rolling, in instances planting fields for the first time, and replanting in others. Fields that held ponded water are noticeably uneven in emergence and early season growth. As the growing season progresses it will be interesting to follow the development in these fields. Earlier planted corn has reached V4 to V5, most soy I scouted are somewhere between just planted and V1, one fully developed trifoliolate. I plan on visiting an early planted soy field later this week and will be interested in its stage of development. Again, I posted another Waterhemp image this week demonstrating the rapid growth of weeds with improving growing conditions.

In Northeast Illinois some were fortunate to plant for several days while others have yet to attempt field work in the month of May. Crop scouting is critical to determine stand counts and the presence of drowned out areas. Waterhemp seedlings can easily be found in fields. For post herbicide applications be aware of weed height recommendations. A general rule is treating most weeds in the 3 to 4 inch stage.