Another week without a hint of precipitation in most of NE Illinois, soy has basically stopped growing and corn fields are struggling to canopy between rows. My thermometer is registering 99 degrees this afternoon. I truly hope to share a different story next week, there is concern on how long these crops can hang on before suffering significant yield consequences.

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 plants 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.

Many areas in Northeastern Illinois are experiencing a level of drought conditions. Corn is wrapping in some fields during the day in response to temperatures and lack of moisture. Soybean growth has slowed and most are hoping for more favorable conditions before applying post herbicides in this crop. When applied under the dry conditions post corn herbicide conditions were less than ideal. We encourage growers to evaluate the effectiveness of the applications within 1 to 2 weeks. Wheat in the area appears to be hastening to maturity, it may be an early wheat harvest in northern Illinois.

Northeastern Illinois is turning dry. Post herbicide applications are taking place in corn fields. Despite dry conditions weed growth and diversity of species has been impressive in some fields, including robust vining weeds including Burcucumber and Morningglory. Early planted corn is at V6 and Soy at V2. I received reports of heavy Alfalfa weevil feeding and below average tonnage from the first cutting of hay in the region. A reminder, mechanical harvest is an effective cultural control of this pest. The Alfalfa weevil has one generation per year and overwinters as an adult. Mowing and harvesting the field removes the insect’s food and shelter. In addition, harvesting the crop can expose the larvae to sunlight which can be lethal. While the Alfalfa weevil window of damage is nearly over, farmers are encouraged to continue to scout for other forage pests that can cause damage in future cuttings including Potato leafhopper.

Much of Northeastern Illinois has had a precipitation-free week. Soils are drying rapidly. Soy planted just before the most recent rainfall event is struggling to emerge in some fields. The soy hypocotyl cannot push through the crusted soil surface. Fields planted in this time period warrant a field scouting trip to evaluate emerged plant population. Most corn is near the V4 stage, Waterhemp has also emerged and is growing quickly in fields. Be aware of size restrictions on both crop and weeds with planned post herbicide applications. Sidedressing of corn with nitrogen and harvesting the first cutting of hay is underway in the region.

Sunshine and heat, finally! Favorable growing conditions in NE Illinois. The sunshine, warmth, and needed rain gave a boost to both corn and soybean that had been slowly trying to emerge and grow. Despite concerns, I have heard few reports of emergence issues with seed sitting in cool soils for extended periods. This past weekend most areas measured between .3 to over an inch of rain. Isolated areas near Channahon and in Kankakee received 2+ inches. Soybean planting is starting to resume in the area.

Mostly favorable growing conditions in NE Illinois. Spotty precipitation slowed some farmers who are trying to wrap up the 2023 planting season. Cooler soils slowed some soybean emergence, especially in high residue No-till fields. Those scouting soybean fields have reported some emerging soy exhibiting discolored cotyledons. Likely causes can include stressful emergence conditions, diseases, herbicide injury from pre-emergent herbicides (likely PPO-inhibiting herbicides whose injury to emerging soybeans is enhanced by cool and wet conditions). If the cotyledons have a distinctive “halo'” on the cotyledon and the soy planted was seed-treated with the fungicide fluopyram (ILeVO), the browning is the result of phytotoxicity caused by accumulation of the fungicide in the cotyledon. We encourage early season scouting but also suggest farmers observe their soybean fields for several days to a week of favorable growing conditions before making rash replant decisions. Soybean are a resilient crop that often outgrow early season issues.