Earlier-planted soybean fields are beginning to turn color, signaling the Beginning Maturity (R7) stage. Other soybean fields are mostly in the Full Seed, R6 stage, and no longer blooming.
Earlier-planted corn fields are looking ugly with areas of the fields showing severe N-deficiency symptoms and dead plants, which is indicative of a root or stalk disease issue. Corn crown rot is suspected to be the cause in some of the fields. I currently have several corn plant roots and lower stalks being analyzed at the U of I Plant Clinic in the hope of determining the cause or causes. Local farmers are preparing for a challenging beginning to their corn harvest in the area.

Black layer is near for some corn fields in the Northeast region. Utilizing the U2U Decision Support Tool – Corn GDD suggests a 108-day Hybrid planted April 25th in Grundy County will reach black layer between September 1st and the 6th. In corn fields scouted, especially those that did not receive a fungicide application, foliar leaf diseases continue to hasten leaf area necrosis and yellowing of plants. This is going to be a challenging year for accurate corn yield prediction from the perspective of in-field variation. Growers are encouraged to sample multiple locations within the field, accounting for pollination differences in ears to more accurately assess predicted yield. Some soy fields are starting to show very limited disease symptoms including Sudden Death Syndrome. This fungal pathogen can survive the winter in both corn and soy residue. Infection takes place early in the growing season, enhanced by cool and wet soil conditions. The visible symptoms we see are the result of a toxin produced by the disease that is translocated to upper canopy leaves. There are several other diseases including Red Crown Rot and Brown Stem Rot that exhibit similar leaf symptoms.

We have caught a very nice break from severe weather and storms, with some pleasant temperatures to boot, as we begin to enter the home stretch of the growing season. Corn fields across northern Illinois are starting to fire, while soybean fields continue to stay green and produce large pods and seeds.

Disease is starting to show up in soybeans. Sudden Death Syndrome (SDS) as well as Septoria leaf spot are the two main diseases I have seen. I have not seen white mold, and have only heard of a few fields so far with Red Crown Rot (a disease that has nearly identical foliar symptoms to SDS). The fields affected by the listed diseases will defoliate quickly, and cap pod fill overall. Soybean fields as a whole have looked great this year, and high yields should be expected if what I have scouted is any indicator.

Corn continues to move towards black layer and physiological maturity. Disease instances remain low even as we approach September. Tip back is something to be monitored closely, as many fields were going through pollination during a heat dome, dealt with wildfire smoke, and week-long overcast conditions. A dry and hot September may accelerate dry down as well. More updates to come next week!

Both corn and soybean fields are maturing well and looking promising… or they suffered from recent heavy rains/winds and are visibly struggling. While flooded fields have mostly drained over the past week, you can still see the evidence of high waters in bean fields where plants were drowning and are now painted in a layer of soil, or in corn fields showing N deficiencies and early dry down. Some areas that needed the precipitation have soaked it up and appear dry again. The precipitation received this month, coupled with the more mild temperatures, will really help the soybeans as they finish off grain fill. As the saying goes: Beans are made in August.

One insect I’ve seen a lot of lately is thistle caterpillar. Thistle caterpillar, the larval stage of the painted lady butterfly, will build a very distinctive web in soybean leaves and cause defoliation. Threshold levels for control have not been met in fields I’ve scouted, but one double crop field I visited had notable pressure. Per Iowa State University Extension, these caterpillars are a migratory pest, coming north from the southern United States and Mexico, and likely do not overwinter in our climatic region.

I visited Ford County this week, and like Champaign County, flooded conditions have returned to areas affected earlier this growing season. The flooding seemed to be a bit worse in the southern part of the county and improved as I traveled north, which is consistent with precipitation estimates from MRCC and rain gauge data from ISWS and CoCoRaHs from the past couple of weeks. To some extent, the flooded areas are already absent of a crop due to early-season flooding. But in a number of fields I stopped at, the current flooding extended into previously healthy crop. That crop is now either dead or has signs of stress, disease, and early senescence, leading to incomplete grain fill, low seed weights, and potential grain quality issues.

In fields or areas not affected by the flooding, soybeans are at or near full seed (R6). Soybean canopies, for the most part, were still relatively clean of disease, but a minority of fields do have some disease symptoms starting to show in patches. Disease symptoms were a bit more prevalent in corn fields visited, primarily gray leaf spot and northern corn leaf blight, but severity was still relatively low, overall. Corn was generally somewhere in the dent (R5) growth stage, getting close to black layer in a handful of fields.

The region has received 9+ inches of rain over the past two weeks, leaving soils saturated, fields muddy, and drainage systems running at full capacity, with limited field activity. Soybeans are mostly at the growth R5 stage and benefiting from the August rainfall, while corn is moving from dough to dent stages as growers are beginning yield checks to see what harvest could look like. Weed pressure remains present, but disease levels are surprisingly low, with only some gray leaf spot and northern corn leaf blight being observed. Northern corn rootworm beetles have become more noticeable over the past few weeks.

Generally, the corn and soybean fields look very good. The exceptions are fields that have been damaged by severe weather, or flooding.
Over the past week, symptoms of Corn Crown Rot have become visible in areas of some fields. What I am seeing is these affected areas are patches of dead, lodging corn plants. Dr. Boris Camiletti, Extension Plant Pathologist, said the photo above appeared to be Corn Crown Rot. A sample is being sent to the U of I Plant Clinic for a diagnosis. Corn crown rot disease infects corn plants in the early portion of the growing season, and the disease is more prevalent in wet, compacted soils.

The heavy storms and even a derecho have passed and we have been left with some gorgeous weather to end the week before some more rain chances next week. Not too many updates agronomically from my last update. Corn has moved into R5 dent across northern Illinois, with many fields at the early stages of senescence. I did find a good amount of tip back in corn in the fields I visited, and I attribute that to the heat dome we experienced coinciding with the end of pollination. The extreme heat and low winds we saw will kill pollen, and lead to lower movement of the pollen that did survive. There will be yield reductions in the fields I saw today, but the severity of the tip back you may see in your fields will align with planting date, and where your fields pollination lined up with the severe heat events we have seen this summer.

Soybeans are looking healthy with little disease. I did not see pockets of SDS as I was expecting, but that may still develop in the coming weeks. Soybeans are moving through pod fill in R5, and were very tall and robust in the fields I saw today.

Overall I’ve found very little disease in the Dekalb sector, with little to no tar spot, and very little disease in soybeans. Cooler temperatures next week may change that, but I feel like I’ve been saying that for weeks now. Tip back and lack of kernel fill is the major concern seen today.

Wet conditions have returned to much of central IL. Following a bit of a dry spell in late July and early August, the Illinois Soil and Water Survey’s weather station in Champaign has registered more than 8 inches of rain over the past 9 days. The recent storms also brought high winds and a tornado in the southwestern portion of Champaign County, near Giblin, leaving pockets of crop damage (mostly corn) in that area. Standing water is also back in low areas of some fields. Many of these areas were already absent of crop due to the same issues earlier in the growing season, but standing water could also be seen in some areas where the crop had survived that early-season stress.

Wind damage appeared to decrease as I continued toward Sadorus and Tolono during my survey of southern Champaign County, although the flooding in low-lying areas persisted. Corn conditions were a bit variable. Many fields still look healthy and green, but some corn fields are starting to “fire”, or lose color in their lower canopy, indicating remobilization of nutrients from those tissues to the developing ear. Most fields range from the late dough (R4) to dent (R5) growth stages; I didn’t find any fields at black layer, or full maturity (R6), quite yet. Some fields are starting to show more symptoms of foliar disease, primarily gray leaf spot, but also some northern corn leaf blight. But with those fields generally at early dent (R5) or later, the level of disease observed is unlikely to have a large impact on yield.

Soybean conditions are also starting to look more variable in the area. Again, many fields are looking healthy with a dense, green canopy and full pods, at or nearing the full seed (R6) growth stage. But some fields are starting to show areas with yellowing leaves, indicating some kind of disease issue. In a couple of those fields, I collected plants and split stems to identify pith symptoms characteristic of brown stem rot. This may also be the issue in other fields I observed with similar foliar symptoms, but there are a number of diseases that often present similar foliar symptoms that may be difficult to differentiate and properly diagnose in the field. Resources are available from the Crop Protection Network to help with identifying these diseases (https://cropprotectionnetwork.org/publications/scouting-for-soybean-stem-diseases), and samples can always be submitted to The Plant Clinic (https://extension.illinois.edu/plant-clinic) to get a lab diagnosis. Having an accurate diagnosis is essential for selecting resistant varieties and developing a successful integrated pest management plan for future growing seasons.

The area has started to show signs of water stress up until today, when we are receiving some rain that was not in the forecast. We have received minimal amounts, but we are not complaining. Due to heat and water stress as well as possible nitrogen deficiency, the early April planted corn at late dent stage has started to senesce. Corn has not reached black layer yet, but will very, soon if the heat remains in the forecast. The early April planted soybeans look good at the R5 to R6 growth stages, but we are hoping for more rain for grain fill. There were no evident pests. Foliar disease has held off due to weather and earlier fungicide applications. Gray leaf spot appears to be increasing in areas of the field that may have missed fungicide. Soybean vein necrosis viral symptoms have become visible in soybeans. Lastly, be on the lookout for stalk rot and standability in corn to know which fields may take priority at harvest.