Illinois Crop Update | June 16, 2023

Russ Higgins – Extension Commercial Ag Educator

Grundy County

Soil Conditions: Moderately Dry (soil is dry, plants may be browning or stressed, water bodies are low)

In northeast Illinois fortunate farmers and farms received measurable rain, those that didn’t continue to watch their crops struggle in drought conditions. While most are familiar with a corn plant’s defense mechanism of leaf wrapping to lessen moisture loss, soy has defense mechanisms as well. Under moisture limited conditions or excessive temperature, soybean plants will flip over their leaves. This exposes their silvery-green underside which reflects more light. This process can reduce temperature stress for the plant until it experiences more favorable conditions. Even under stress, I noted the first flowers on soy plants this week. While our preference is to have a stress-free growing season, stress during the vegetative stages of both corn and soy are less likely to have yield impacts when compared to the reproductive stages if conditions improve. Scouting V10 corn, I noted an insect egg mass on an upper leaf hatching nymphs. What did I find? Confirmed by Dr. Nick Seiter, University of Illinois entomologist, as stink bugs.

Figure 1: Soy under drought stress – leaf flipping.

Figure 2: Stink bugs hatching on corn.

Doug Gucker – Extension Local Food Systems and Small Farms Educator

Macon County

Soil Conditions: Mildly Dry (soil is drier than normal, plant growth may have slowed)

My area is dry, but cool nights and cloudy or hazy days are helping to keep stress on the lower end. Corn fields are in growth stage V6 to V10+ for the majority. Corn height is shorter than normal. Soybeans fields vary from V4 to R1 and are shorter than usual. Area wheat fields are looking good with leaf leaves clean and green with harvest getting close.

Figure 3: Corn growth varies from V6 to V10+.

Figure 4: Still seeing attempts to control “too tall” waterhemp.  Soybeans growth stages V4 – R1.

Figure 5: Area-wide wheat fields are looking good.

Talon Becker – Extension Commercial Agriculture Educator

Champaign County

Soil Conditions: Moderately Dry (soil is dry, plants may be browning or stressed, water bodies are low)

Although some rain fell in much of the area this past Sunday, total rainfall was low (0.14” at the Illinois Climate Network (ICN) station in Champaign) and conditions remain dry in Champaign County.  ICN soil moisture data show levels below the plant wilting point at 2” and 4” depths, however, at least where these instruments are in place, plant available moisture is still present at 8” and deeper.  The lack of soil moisture at the shallower depths is evident when driving around the countryside.  Corn plants in drier areas of fields are showing rolled leaves even in the morning hours.  By the afternoon, the signs of moisture stress are more prevalent.  Most corn plants are somewhere in the V5-V8 stages, and at that size, have at least some roots that are deep enough to reach the soil moisture still available.  Soybeans may be struggling a bit more at this point, and their growth seems to have slowed in most fields.  The plants still look relatively healthy, and the first flowers are starting to appear.  But with little rain in the extended forecast, these early flowers are unlikely to contribute much to final pod counts.

Figure 6: Corn field at V5-V6 showing slight leaf rolling at 10am – June 15, 2023.

Figure 7: Soybean plant in dry, cracked soil showing first flower – June 15, 2023.