July 3rd, 2025 Scouting Report for Cedar, Knox, Pierce counties in Nebraska and Yankton County in South Dakota
(Scroll down for Illinois counties)
Reported by Tristan Mueller
Key Takeaways:
- Currently the CropVoice network is not indicating an above-ground fungal foliar disease that warrants in-season treatment.
- For irrigated soybeans, the forecast for white mold risk for 15” rows increased slightly more than predicted last week, especially in Cedar County. Within the next 10 days, the whole region will be in the high-risk category for soybeans planted at 15” row spacing.
- White mold spore-producing structures may be developing now. If you have fields that you know had white mold two years ago, now is the time to take a closer look at your hot spots for apothecia (mushroom-like structures).
Currently the CropVoice network is not indicating an above-ground fungal foliar disease that warrants in-season treatment. We will continue to monitor plots daily and conduct regular tissue sampling and will send a Disease Alert if any of your fields are at risk.
We have found limited amounts of Septoria brown spot and bacterial blight to date. Any other pathogens reported have been very sporadic and the plants have not shown infection.
This last week has seen relatively normal temperatures. Of course, ‘relatively normal’ heat has a bit of a different meaning this time of year, and the heat has decreased the risk of white mold infection in dryland soybeans in some areas. During the last week however, the crop also received much needed rain, which has made conditions more favorable for white mold development.
However, when it comes to irrigated soybeans, the forecast for white mold risk for 15” rows increased slightly more than predicted last week, especially in Cedar County. Within the next ten days, the whole region likely will be in the high-risk category.
Current (left) and forecasted (right) weather-based model of white mold risk for irrigated fields planted in 15” rows. Red lines indicate major roads, with Highway 81 running down the middle of the image; Sioux City at right center. (Credit: InnerPlant Modeling)
As you’d expect with row closure ongoing, 30” irrigated beans are behind this risk forecast a bit, but are catching up. We expect medium risk creeping in from the east and along the Missouri River bottom in the next ten days.
Current (left) and forecasted (right) weather-based model of white mold risk for irrigated fields planted in 30” rows. Red lines indicate major roads, with Highway 81 running down the middle of the image; Sioux City at right center. (Credit: InnerPlant Modeling)
We have been searching for white mold apothecia (mushroom-like structures) in known white mold hot spots. Spores infect plants primarily through the flowers as they senesce, but damaged plant tissue can be another avenue for the spores to infect.
The plant surface needs to be covered with available moisture for infection to take place – usually that means the canopy must be closed. In Nebraska, there is a wide range of how closed the rows are, so keep that in mind when making your fungicide application decision. Once there is an infection of the flower, the fungus will infect the pod and eventually spread to the stem.
White mold disease lifecycle. (Credit: Crop Protection Network)
White mold will not become visible from the road until mid-August, but spore-producing structures may be developing now. If you have fields that you know had white mold two years ago, now is the time to take a closer look at your hot spots for apothecia (mushroom-like structures).
July 3rd, 2025 Scouting Report for Tazewell, Woodford, McLean, Livingston, and Champaign counties in Illinois
Reported by Robert “Bob” Starke, Ph.D.
Key Takeaways:
- Currently the CropVoice network is not indicating an above-ground fungal foliar disease that warrants in-season treatment.
- If you have fields that you know had white mold two years ago, those fields are at a higher risk than the average fields in the area. Now is the time to take a closer look at your hot spots for apothecia (mushroom-like structures).
- The drier, hot weather is expected to continue, which reduces the increase in risk of frogeye leaf spot and other pathogens in the Illinois CropVoice network. Areas to the west and north of the Illinois CropVoice network are moving into medium risk for frogeye this week.
Currently the CropVoice network is not indicating an above-ground fungal foliar disease that warrants in-season treatment. We continue to monitor plots daily and conduct regular tissue sampling and will send a Disease Alert if any of your fields are at risk.
CropVoice sensor plot being monitored daily.
Through tissue sampling, we have found limited amounts of Septoria brown spot and bacterial blight. Any other pathogens reported have been very sporadic and the plants have not shown infection.
At this point in the season, we are searching for white mold apothecia (mushroom-like structures) in known white mold hot spots.
In a field just east of El Paso, Illinois, the apothecia pictured below was found growing from a sclerotia (hard black structure that allows the fungus to overwinter). The apothecia releases ascospores that infect the soybean plant through decaying flower tissues and result in a white mold infection.
White mold apothecia growing from a sclerotia found in field; bottom of soybean leaf for scale.
As we evaluate disease risk with the disease triangle, we know that the sclerotia are present in the fields and that soybeans are susceptible. It now comes down to the environment. With a cool, closed, damp canopy, more apothecia will grow. If it is hot and dry, fewer apothecia will grow.
The next two to three weeks will determine the severity of white mold infection in most fields. Currently, it is difficult to find a single apothecia, even crawling on your hands and knees. In known hot spots, however, multiple sclerotia are easy to see on the soil surface, but most are not yet producing apothecia.
White mold will not become visible from the road until mid-August, but the beginning of the white mold lifecycle is happening now. If you have fields that you know had white mold two years ago, those fields are at a higher risk than the average fields in the area. Now is the time to give those hot spots an extra look to see any apothecia as shown above. Keep in mind that white mold risk in the area remains relatively low based on our InnerPlant white mold disease forecast for Illinois.
Japanese beetle feeding has greatly increased over the last week. Damage is often greatest along field edges. Populations are rapidly increasing, but it takes 20% defoliation in the soybean reproductive stages to warrant treatment. Watch nearby roses and crabapple trees as well, as this is the Japanese beetles’ preferred food.
Japanese beetles feeding on soybean leaf.
A key limiter on disease pressure in the area has been moisture. As shown in the picture below, nearly the entire Illinois CropVoice network, except for the area east of El Paso, has been dry these past two weeks. Last week has been even drier.
Scale shows rainfall percentage of normal (Credit: NOAA National Water Prediction Service)
Looking forward, the dry weather continues along with moderate heat. This weather pattern reduces the frogeye risk forecast. The change in frogeye disease risk in the area is less than 2%, meaning no major increases in risk. Fewer areas have crossed into the medium risk category this week, mainly to the west of the Illinois CropVoice network.
Forecasted change in frogeye leaf spot disease risk for next 10 days based on weather, leaf moisture, and other variables. (Source: InnerPlant modeling based on the work of Damon Smith at the University of Wisconsin)
Catch up with any scouting reports you missed by following the links below:
Scouting Report for June 26, 2025
Scouting Report for June 12, 2025
Scouting Report for May 29, 2025
Scouting Report for May 15, 2025