It’s hot! Temperatures exceeding 90 degrees for consecutive days in NE Illinois. Despite the ambient temperature both corn and soy fields are holding up well, but additional rainfall would be welcome. Most corn fields are at or near R3, the milk stage. Some ears have visible aborted kernels at the ear tip. There has been minimal to no leaf disease in corn fields that I have visited, but plan on staying diligent and listening to local reports and regional reporting resources including the Corn ipmPIPE for Tar Spot https://corn.ipmpipe.org/tarspot/ to be aware of areas where crop disease has been detected. The soy crop has responded to recent rains with increases in vegetative growth and most fields are at or near R3 or Beginning pod. When scouting fields, it is still not too late to look for symptomology of herbicide damage in fields.

I’ve received several reports of corn rootworms breaking through pyramided Bt traits over the last couple of weeks. Most of these are in the usual areas north of I-80, but I was able to collect a population from Sangamon County last week and had reports from Putnam and Bureau. Continuous corn is virtually always the culprit in these cases. We are always looking for both western and northern corn rootworm populations to bioassay; if you have large numbers of adults and wouldn’t mind us coming out to collect them, please don’t hesitate to contact me.

With my area still listed as being in “Moderate Drought”, crops are still looking good. Most soybean fields are in the “full pod” or R4 stage. I surveyed 50 consecutive soybean fields on my drive and 13 (26%) of those fields had weed escapes present across the field and volunteer corn was not considered a weed escape. This is another effect of this year’s dry spring weather on the effectiveness of residual and post-emergent herbicides. Most corn fields are in the late “milk” or R3 stage or beginning “dough” or R4 stage. There is some tipback on the corn ears present. Very little leaf disease is showing up in area crop fields, which is common in a drought.

It was a good sign to see that the corn canopy was collecting as much sunlight as possible with little sunlight hitting the ground. We can’t complain, but would love more rain for corn grainfill. The insecticide application eliminated Japanese beetles and most disease. If you visit field edges where fungicide coverage was a scarce, you will find tar spot on lower leaf and gray leaf spot moving up the plant. Soybeans are hanging in there with no more insect pressure thanks to a recent insecticide application. Septoria brown spot is in the lower canopy.

Crop is moving along. The high temperature next week are going to be tough with no moisture in the forecast. Corn stalks have moved the potassium from the lower nodes towards the ears, weakening stalks.

This week, I visited fields in central Champaign County. With much of the recently forecasted rain missing the area, soils are starting to dry up again. Digging down in a few field, there is still some moisture present a few inches below the surface, but that too is starting to dry. Plants do not looked stress at this point in time, but that could change quickly with a warm week ahead of us an minimal chances for rain in the current forecast. The vast majority of corn fields I visited had finished pollination, and were generally at blister (R2) or milk (R3) stages. Soybeans were generally at beginning pod (R3) to full pod (R4). Weed control was variable, with most pressure coming from waterhemp, and a few morning glories here and there. From the road, many soybean fields still look rather clean, but waterhemp pushing through the canopy is also starting to become a more common sight in the area.

Nice weather for corn pollination. Still need consistent rain showers of .75-1.5” per week to maintain yield potential. Soybeans are R2-R3.
Insect pressure is moderate.

Wheat harvest has mostly wrapped up in NE Illinois. This week fungicide applications started in earnest, I observed fields sprayed by plane, helicopter, ground rigs and a drone! Many growers simply include a fungicide application in their management plan; however, we still encourage scouting to determine disease pressure before committing to a fungicide application. Being aware of requirements and favorable conditions for certain diseases. Examples include Northern Corn Leaf Blight and Tar Spot, both require extended periods of leaf wetness (6 – 7 Hours) for establishment. With recent rainfall many have noted early morning mist settling over some fields, facilitating the leaf wetness requirement. For those still considering an application, the Fungicide Efficacy Guides (from Land Grant Universities) have been updated for 2023 and can be accessed at https://cropprotectionnetwork.org/news/fungicide-efficacy-guides-updated-for-2023
Will the dry weather in June and resulting shorter corn plants have an effect on final yield? One of the things I have noted scouting some corn fields is the amount of light reaching the ground. In my experience during good growing seasons very little light reaches the ground at R1. As the picture demonstrates, that is not the case in all fields this year.

During my 40-mile crop survey across DeWitt, Macon and Piatt counties, I noticed several things. First, the very spotty nature of the recent rains with water standing in a field and a mile away it was powder dry. Second, it seems that residual weed control is not lasting long enough in some 30-inch row soybeans. I saw applicators in two fields spraying to control amaranth in 30-inch soybeans and other fields that had been sprayed in the past week. Third, the effects of the violent storms in late June that crossed the area are particularly evident in corn fields showing tattered leaves or elbowed stalks.
Soybeans for the most part are in the R3 growth stage with early planted fields approaching the R4 stage. Corn field growth stages varying from R2 (blister) to R3 (milk).