Crop conditions across Iowa continue to look pretty good overall. Some isolated areas might not look as good due to the wetter conditions or recent storm damage. Soybean gall midge, corn rootworm, weed escapes, and foliar diseases/fungicide application decisions were some of the concerns seen or heard from extension field agronomists in the last week. Read on for more specifics about what is happening in crop fields around the state.
Leah Ten Napel (Region 1):
Cherokee, Ida, Lyon, Monona, O'Brien, Osceola, Plymouth, Sioux, Woodbury counties
“Farmers across NW Iowa are optimistic about the crops this growing season. With adequate moisture, moderate temperatures and little pest pressure, the crops are looking very good. The biggest pest we have been dealing with this season waterhemp. Disease and insect reports have been low at this point, but it is recommended to continue scouting to catch pest before they turn into larger, yield affecting issues.”
Gentry Sorenson (Region 2):
Buena Vista, Clay, Dickinson, Emmet, Hancock, Kossuth, Palo Alto, Pocahontas, Winnebago counties
“Rainfall ranged from 0.5 inch to 2.5 inches over the last week. Currently the corn stage is late vegetative to R2, and soybean growth stage is R1 to R2. Several phone calls and field calls pertained to off target herbicide injury to soybean and alfalfa fields. Rainfall has made cutting and baling hay difficult over the past several weeks. Post emergence spraying is nearing completion, but I do know of some fields that still need a post application in soybeans. With the rain and wind, post application of herbicides has been difficult this year. I have found very low levels of gray leaf spot in corn fields that I have visited.”
Angie Rieck-Hinz (Region 3):
Cerro Gordo, Franklin, Hamilton, Hardin, Humboldt, Webster, Worth, Wright counties
“Corn diseases continue to be elusive to find. However, on Monday, July 14, Gentry Sorenson and I found northern corn leaf blight, Physoderma, common rust, and the beginning of gray leaf spot all in the same corn field planted at the Northern Research Farm in Kanawha. Continue to watch your corn growth stages and continue to scout. I have, on occasion, found Septoria brown spot in soybeans, which is a very common disease. To be honest, I would have expected to find it more frequently than I have been this year, but other than this disease, I have found very little disease to date in soybeans. Insect pressure in both crops has been very low to non-existent. Oat harvest has started in NC Iowa.”
Terry Basol (Region 4):
Benton, Black Hawk, Bremer, Butler, Chickasaw, Floyd, Grundy, Howard, Mitchell counties
“Crops in NC and NE Iowa are looking really good. Corn is very near or at the VT stage for most of the acres. Continue to scout corn for foliar diseases, as we have conducive environmental conditions for disease development, particularly gray leaf spot. For more information and help in making a fungicide application decision, check out the ICM article titled; “Before You Pull the Trigger: 2025 Fungicide Smarts for Corn”. Also, there’s a new tool available on the Crop Protection Network to help assess disease risk called the Crop Risk Tool. For corn it provides risk for gray leaf spot and tar spot when corn is between V10 and R3. According to the Iowa Mesonet, we are on track to a little above for Growing Degree Days at the NE Iowa Research and Demonstration farm near Nashua and below average for Stress Degree Days (which is optimum for corn pollination) (see figure 1 below). Soybeans range from R2 (open flower at one of the two uppermost nodes on the main stem with a fully developed trifoliolate leaf node) to R3 (pod is 3/16” long at one of the four uppermost nodes on the main stem). Second pass postemerge herbicide applications have been conducted for most of the area for the acres needing it. Continue to scout for disease and insect activity. Second cutting of hay in the area is 45 and 63% completed in NCand NE Iowa, respectively according to the July 13 USDA-NASS Crop Progress Report. Oats have nearly all turned color, with harvest beginning for the earliest planted acres. We’ve received a fair amount of rainfall over the past couple of weeks. Specifically at the research farm near Nashua the Iowa Mesonet station information shows that two weeks ago (June 30 – July 6) the farm received a total of 1.38 inches, and last week it received 1.72 inches. For the 2025 growing season (April 1 to July 13), the farm has received 18.9 inches, and in July so far 3.1 inches.”
Josh Michel (Region 5):
Allamakee, Buchanan, Clayton, Delaware, Dubuque, Fayette, Jones, Linn, Winneshiek counties
“Severe weather brought heavy rainfall and some isolated wind damage to several fields last week. Lighter amounts of 0.5 to 1 inch of precipitation was reported in counties along the Minnesota border, while areas along and south of Hwy 20 from Independence to Dubuque generally received 3.5 to 5 inches of precipitation. Crop damage from high winds and isolated hail was also reported in several areas in Delaware, Dubuque, Jones and Linn counties. Crops continue to grow rapidly, and many fields are quickly approaching reproductive stages. Most corn fields are generally at or near VT, while most soybeans have reached R1 to R2. Oats continue to mature, with approximately 60 percent having turned. Some of these fields could be harvested for grain if the forecast allows. The second cutting of alfalfa was in full swing before the heavy rainfall last week. I’d estimate that two-thirds of second cutting has been put up so far. Despite warm temperatures, many pastures continue to look fair to good with the recent rainfall over the past couple weeks. The majority of field calls this past week centered around insect and disease management, late-season weed management, and assessing various herbicide drift and crop injury reports.”
Meaghan Anderson (Region 7):
Boone, Dallas, Jasper, Madison, Marshall, Polk, Story, Tama, Warren counties
“Central Iowa recorded another week of significant rain with most of the area receiving 1 to 3 inches and some areas receiving significantly more. Crops are hopefully using this moisture quickly, with R1/R2 corn using over 0.25 inches of water per day. While walking corn fields late last week, low levels of numerous foliar diseases were present, with northern corn leaf blight as the most common fungal disease and bacterial leaf streak as the most common disease I found overall. Many corn fields look to be in excellent shape, but the significant recent rainfalls have made yellowing and N deficiency more apparent under the canopy. Soybeans are in the R2/R3 growth stage and seem to have minimal disease issues so far. Insects are present in both crops – Japanese beetle and soybean gall midge in soybean, corn rootworm in corn. Most phone calls in the last week have been about continued issues with off target herbicide movement, weed control failures, fungicide decisions, and mystery weeds.”
Rebecca Vittetoe (Region 8):
Iowa, Jefferson, Keokuk, Poweshiek, Washington, Johnson counties
“July is typically a drier month, but that hasn’t held true so far. Rainfall totals varied widely over the past week, with most areas receiving between 1 to 3 inches. Some isolated spots, however, saw over 6 inches. Overall, crops continue to look very good. Corn is mostly at VT/R1 to R2, and soybeans range from R2 to R3. With the wet conditions, I’ve received plenty of questions regarding disease pressure and fungicide decisions. In the last week I’ve observed low levels of several corn diseases—including gray leaf spot, Physoderma, northern corn leaf blight, holcus spot, tar spot, and bacterial leaf streak. Be sure to scout your fields. I’ve been seeing minimal disease pressure in soybeans so far as well, mostly bacterial diseases. In terms of insects, corn rootworm remains a major topic—particularly following the recent rain events that also brought wind with them, resulting in some root-lodged corn. Japanese beetles, fall armyworms (a bit early this year), and corn earworms were others insects I’ve seen or have heard about in the last week. Finally, I’ve received numerous weed-related inquiries, mainly around identification or concerns about weeds surviving herbicide applications.”
Virgil Schmitt (Region 9):
Cedar, Clinton, Des Moines, Henry, Jackson, Lee, Louisa, Muscatine, Scott counties
“Most of the area I cover received 2 to 5 inches of rain last week. Scott County had major flooding in low-lying areas near rivers and streams, and two tornadoes were confirmed. In the big picture, damage from the tornados appears to be minimal. Most corn is V16-R1 and generally looks good. Soybeans are mostly R2 and generally look good. Japanese beetles continue to be evident in many soybean fields last week. Calls last week mostly centered around fungicides and herbicide drift.”
Aaron Saeugling (Region 10):
Adair, Adams, Cass, Clarke, Decatur, East Pottawattamie, Fremont, Mills, Montgomery, Page, Ringgold, Taylor, Union, West Pottawattamie counties
“July has had difficulties this year with most locations receiving needed rain in the past 10 days. Portions of SW Iowa would border on excessive rainfall events. However, most of the rain is a welcome site. With the rain came wind events that broke corn off and caused some leaning corn in fields. Overall crop conditions look excellent. Fungicide application will begin this week despite low disease levels at this point in the growing season. Future disease and insect pressure may be weeks away with the cooler and moist conditions. Surrounding states are reporting high Western Bean Cutworm and Japanese beetle captures. Producers need to continue to scout fields for the next few weeks. Soybeans are welcoming the warmer, wetter weather and are looking good. Isolated weed control issues have been observed; however, at this point insect pressure appears low at this point. Pastures look good for this time of year and second cutting to third cutting alfalfa has been a challenge to harvest with recent rains.”
Logan McCrea (Region 11):
Appanoose, Davis, Lucas, Mahaska, Marion, Monroe, Van Buren, Wapello, Wayne counties
“Over the last week, the region received precipitation anywhere from around 1 to 3 inches, with localized amounts coming in higher or lower than that range. For the most part, large wind/hail damage did not occur in the area though some smaller hail may have tattered the leaves on some fields. The Wapello/Davis county area is one of the few moderate drought areas left in the state, and unfortunately missed out on some of the higher rainfall amounts but received some precipitation at least. Early planted corn is finishing up pollination, while early planted soybeans are in full bloom and will be starting to put on pods soon or may have begun already. Both crops generally look very good across the area. Forages are getting plenty of rainfall for regrowth, while the precipitation is making cutting windows rather distinct but still giving producers some good chances to get hay put up. Insect wise, Japanese beetles are out and about, and soybean gall midge was found in a field in Marion County (had been confirmed in this field in prior years already).
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- Field Agronomist in EC/SE Iowa