Timely rainfall across our region brought much-needed relief, helping ease the extreme heat last week and providing more favorable conditions for both the crop and fieldwork. While the cooler temperatures are welcome, they may also create an environment that allows corn and soybeans diseases observed earlier this summer to become more active again. The prolonged stretch of hot halted disease progression over the past few weeks, but we’ll continue to monitor fields closely.

Overall, the crop remains in good condition as corn transitions from pollination into grain fill and soybeans move into pod fill. Continued rainfall over the next few weeks will be critical to help maximize yield potential and carry the crop through the remainder of the growing season. Fungicide remains in full swing this week, with acres being treated by drone, helicopter, airplane, and ground sprayers. Growers work to protect crop health during these key reproductive stages.

Fungicide applications are in full swing this week. Crop dusters, drones, and helicopters fill the sky as they apply to fungicide to protect our crops from unwanted diseases. The weather continues to be unbearably hot and uncomfortable for us and corn plants this week. Soybeans continue to grow looking healthier and fuller by the day.

Earlier planted soybeans continue to look better than later planted. Most growers believe the difference is largely due to the cold snap we saw in early May. Beans planted before that point emerged and grew rapidly. Beans planted after stumbled and have struggled to catch up since that point.

Fungicide application in beans has begun, but more growers seem to be questioning if the investment is worth the price. Some growers are adding untreated check strips to gauge if the investment has paid off enough to stay the course or if the investment has been less impressive. Should check strips display the latter, it seems that growers would be more prone to step back their total fungicide-treated acreage in the future rather than exiting the practice entirely.

The most significant development in the soybean crop has been the sudden, early appearance of Red Crown Rot with reports coming in shortly after Independence Day.

The very western portion of Region 4 (Pike County, Illinois) seems to be a focal point of such early and severe foliar symptoms. In some cases, nearly 25 percent of plants in an afflicted portion of the field display mottling, yellowing, interveinal chlorosis/necrosis, or outright plant death. The level of symptomology in some locations appears to be about 2 to 3 weeks ahead of previous seasons with perithecia (red fruiting structures) already evident on the lower stem and upper root material.

While much of this early and severe symptomology seems focused on the Pike County area, Red Crown Rot is appearing in other portions of the region as well. Growers across the region are watching and waiting to see if management techniques can withstand this early onslaught, and some other diseases run the risk of being misdiagnosed as RCR.

Double crop soybeans seem to have had enough moisture to get started well.

The corn crop has done a stellar job of establishing kernels. Pollination, despite some occasional tassel wrap, seems to have largely gone well. Gray Leaf Spot and Northern Corn Leaf Blight have begun to make an appearance, and fungicide applications are in full swing.

One senses a tangible shift toward much more drone fungicide application this season. It has not been uncommon to encounter drone trailers parked here and there across the countryside. In some locations, one has a gut feeling that drone-based applications may be surpassing aerial.

Herbicide misapplications continue to be reported in both crops at a level that seems to rise above and beyond previous experience. The industry will want to debrief and strategize following harvest to minimize issues next season.

Most corn and soybeans in Douglas County have progressed into flowering stages. The primary exceptions to this are areas of fields where early season inundation led to crop stunting as well as a handful of fields where planting was delayed due to wet conditions, which now contain soybeans. These fields, as well as the few wheat/double-crop soybean fields I found, have soybeans ranging from late VC to early V4. Corn that has entered reproductive growth is still in the early stages, generally R1 (silking) to early R2 (blister). Developing pods can be found in the lower canopy of many soybean fields (R3). Foliar disease issues still appear to be minimal in the county. Low spots in soybean fields still have a visibly lighter color as they try to recover from saturated soil conditions and possible soil-borne pathogen pressure. In corn, I found a couple fields with some Physoderma brown spot/stalk rot symptoms starting to show. This pathogen doesn’t generally cause economic losses, but it may be taken into consideration when prioritizing fields for harvest to minimize loss potential from lodging (https://cropprotectionnetwork.org/encyclopedia/physoderma-stalk-rot-of-corn).

Fungicide season is wrapping up for both corn and first crop soybeans. Varying reports of corn pollination issues which could be attributed to weather conditions during pollination or early grain fill. Soybeans look great and double crop soybeans are really taking off!

A favorable week for crop growth in the northeast region of Illinois. Corn is pollinating, despite predicted 90 degrees plus highs this week, most fields have adequate moisture and should not suffer despite elevated temperatures at this critical stage for the corn crop. I enjoy my early morning coffee looking across several corn and soy fields. This past week I noted most mornings start with a mist or fog. The mist does not come directly from the corn and soy crops, even though both put water vapor in the air through the process of transpiration. The morning mist is the result of the cooling of the moist air. As the air cools overnight, it reaches its “dew point” and can no longer hold water as a gas, causing water vapor in the air to turn into liquid droplets. Of significance to those scouting for crop diseases, the morning mist extends periods of leaf wetness, a favorable requirement to several fungal leaf diseases. This week, with the appearance of brace roots in the corn crop, the question of underground root expansion was raised. There are many limiting factors to root growth, too much or limited moisture, soil compaction or other natural barriers. However, the general suggestion is that root expansion in the corn crop continues through pollination. At this point the crop redirects energy toward grain fill. By this time with favorable soil structure, it is not uncommon for corn roots to extend to six feet in depth. Our soy plants tend to generate roots further into the vegetative stages, to R5 and R6, beginning and full seed.
The corn crop is R1 with kernel fertilization underway. Soy is between R2, full flower and R3, or beginning pod. Despite favorable conditions for leaf diseases, I have yet to see an outbreak of tar spot on corn or soy leaf disease in fields I have scouted. Growers are encouraged to remain diligent with both field visits and local reports.