Regional Crop Update: June 22 - June 30, 2026

Regional Update: 

As June comes to an end, corn fields around the state are in the mid to later vegetative stages and soybeans are now mostly in the reproductive stages. Field activities this past week have included starting to make second cutting hay, post emergence herbicide applications, and in-season nitrogen applications. Observations or issues being seen in fields include yellow looking crops in the wetter parts of the state, herbicide injury, Japanese beetles, soybean gall midge, and low disease levels (anthracnose leaf blight, bacterial leaf streak, tar spot, septoria brown spot, and bacterial blight). Read on for more specifics on what extension field agronomists are seeing and hearing around the state. 

Leah Ten Napel (Region 1)

Cherokee, Ida, Lyon, Monona, O'Brien, Osceola, Plymouth, Sioux, Woodbury counties

"Most herbicide applications have wrapped up as soybeans enter reproductive stages and corn reproductive stages are not too far away. Most calls last week were on chemical misapplications or spray drift issues. Insect and disease calls have been low, but I suspect those will pick up soon. Gray leaf spot will be one to keep an eye out for in corn. Soybean gall midge is a pest to keep an eye out for in soybeans. Use the Crop Lookout tool on the Crop Protection Network to stay in the loop on what’s being seen across the state and U.S.! Corn and soybeans are both looking strong at this point, although lack of moisture has been a concern in some areas of the NW region. Precipitation over the weekend and the beginning of this week was welcomed, but these systems brought along some storm damage as well. Wind and hail damage have been reported. Severity has been extremely variable. Depending on the stage of the crop, extent of damage and crop insurance plans, next steps will look different for different fields/farmers. Talk with your agronomist and crop insurance agents to walk through your specific situation. 

One of the big questions we often get with hail damage is whether to apply a fungicide because of hail, to go forward with a planned application or whether to forego the application completely. A common misconception is that hail-damaged crops will be at a higher risk for disease infection. Note that our fungal diseases like gray leaf spot in corn or frogeye leaf spot in soybeans do not require wounding to infect the plant whereas bacterial diseases will more commonly infect the plant through open wounds.

• Nathan Kleczewski, plant pathologist at the University of Illinois, did a nice job summarizing the research from various universities looking at the impact a foliar fungicide application has on hail damaged crops in this article here: http://cropdisease.cropsciences.illinois.edu/?p=1174.

Additional helpful links:
Hail on Corn in Iowa
Hail on Soybean in Iowa
Fungicide Use on Hail Damaged Corn and Soybean
Lodging: mid- to late-season
Damage to Corn Plants by Strong Winds"

Angie Rieck-Hinz (Region 3)

Cerro Gordo, Franklin, Hamilton, Hardin, Humboldt, Webster, Worth, Wright counties 

“Soybeans are R2 and finally are starting to look decent. I have seen no disease or insect pressure in soybeans, except for one thistle caterpillar. People are just finishing up post applications in beans and a few second pass post applications have been made in soybeans. Japanese beetles are starting to show up.  Corn is V8 – V13. I found gray leaf spot last week, but very low incidence and severity.  I have yet to find tar spot, but I suspect it is present in some fields. Corn post spraying is nearly complete as is sidedressing. North-central Iowa finally got some much-needed rain with farmer reports from 0.6 to 2.5 inches. Herbicide complaints are still dominating phone calls.”

Terry Basol (Region 4)

Benton, Black Hawk, Bremer, Butler, Chickasaw, Floyd, Grundy, Howard, Mitchell counties 

"Corn and soybeans are shaping up and looking good for north-central and northeast Iowa. Corn ranges from V8–V10, and soybeans are beginning R1. Early – mid season field operations for corn are primarily wrapped up, with the next decision being fungicide applications. Foliar diseases that are starting to show up in low incidences so far include northern corn leaf blight and tar spot. With the current and forecasted hot temperatures, watch for gray leaf spot. For more information on identification and management of foliar diseases, go to the Crop Protection Network.  Check the Crop Lookout map to see if there have been any foliar diseases reported for your county. For most of the soybean acres in the area, post-emerge applications have been completed, or are very close to being finished up. Oats are also looking good and are currently starting to turn at the Northeast Research and Demonstration Farm. We had a good rain event in the area this past Sunday (June 28) with rainfall amounts ranging from 0.8 to 3 inches. According to the Iowa Mesonet, the Northeast Research and Demonstration Farm received 2.93 inches of rain from June 14 through June 29, and a total of 3.99 inches for the month of June.” 

Josh Michel (Region 5)

Allamakee, Buchanan, Clayton, Delaware, Dubuque, Fayette, Jones, Linn, Winneshiek counties

 “A few dry days last week allowed many producers to start getting caught up on post-herbicide applications and harvesting the second crop of alfalfa. That said, several rounds of scattered showers came through the area with totals ranging from 0.50 to 1 inch in some areas. A line of severe storms also came through the region along Highway 20 on Sunday. Some areas received up to an additional inch of rainfall, while being accompanied by high winds up to 60 mph. Weed management continues to be the biggest concern as many weeds continue to grow very rapidly. In general, most of the corn is around V6–V10, while soybeans are at V3–R1. Small grains and forages continue to look good with all the recent rainfall. Some of the early-planted oats are just beginning to turn color. There have been some isolated reports of lodged oats and leaning corn from the recent severe weather. Most of the corn should upright itself within several days. The majority of field calls over the past week continue to be centered around weed management, as well as herbicide drift and injury.”

Meaghan Anderson (Region 7)

Boone, Dallas, Jasper, Madison, Marshall, Polk, Story, Tama, Warren counties 

 “Central Iowa had a much drier and cooler week last week, with most of us receiving less than a half inch of rain. It’s the time of year now where we’d really like to see a rain in the coming days as corn nears peak water use. Corn is now reaching the “teens” for vegetative stage, with many fields V10+. A few fields appear quite close to tassel and may start showing a tassel here or there before the 4th. Diseases are showing up more regularly but still at very low levels; bacterial leaf streak and tar spot are the most common finds in corn. Soybean are mostly in the R1-R2 growth stage, though they’ve been slow to flower and some fields may not be at 50% bloom yet. Yellow areas are not difficult to find in both corn and soybean between prior standing water and iron deficiency chlorosis. Most questions in the past week have been about weeds - herbicide injury to crops, identifying weeds, killing tall weeds, etc.”

Rebecca Vittetoe (Region 8)

Iowa, Jefferson, Keokuk, Poweshiek, Washington, Johnson counties 

“Precipitation totals last week ranged from 0.5 to 1.8 inches across the counties I cover. Corn ranges from V9–V12 and soybeans are V5–R2. Yellowing in corn and soybean fields is not uncommon especially in thinner or more poorly drained soils as a result of our wetter conditions. Field activities this past week have included postemergence herbicide applications in soybeans, y-dropping nitrogen in corn, and starting the second cutting of hay. From a disease perspective, I’ve found anthracnose leaf blight in corn and bacterial leaf streak. In soybeans, I am seeing septoria brown spot bacterial blight. With the warmer and more humid conditions, gray leaf spot is a disease to have on the radar. Japanese beetles are out and about, and in the next week or so I’m expecting to see adult corn rootworm beetles emerging. Soybean gall midge was found in a Poweshiek County soybean field on June 29. This is a newer pest, especially to this part of the state. Additionally, I confirmed palmer amaranth in a soybean field in southern Washington County. This is a good reminder to keep an eye out for this weed as it can easily be confused with waterhemp, especially in the vegetative stages Questions this past week have been on weed management, herbicide injury, weed ID, and disease concerns in corn.” 

Virgil Schmitt (Region 9)

Cedar, Clinton, Des Moines, Henry, Jackson, Lee, Louisa, Muscatine, Scott counties

“During the last week, the counties I cover have generally received 1.5 to 2.5 inches of rain south of Highway 30, with heavier amounts locally. North of Highway 30, rain tapered off to between 0.5 to1.5 inches near Highway 20. Most corn fields are V13–V15 and look good. However, some fields continue showing nitrogen deficiency symptoms in poorly drained areas. Most soybeans are mostly R1–R2 and look good except for areas where the soil is too wet. Waterhemp continues to be a major problem. Small grains and forages also are doing well. Some oats fields are starting to turn color. A little second cutting hay has been cut. Calls last week mostly centered around weed management, poor looking soybeans, herbicide drift, fungicide applications on corn, and nitrogen deficiency symptoms in corn.”

 Aaron Saeugling (Region 10)

Adair, Adams, Cass, Clarke, Decatur, East Pottawattamie, Fremont, Mills, Montgomery, Page, Ringgold, Taylor, Union, West Pottawattamie counties 

“Corn is moving right along with the warm temperatures. Most corn is V10–V12, and I have yet to see any tassels but should not be far off. Be scouting for corn disease in the coming weeks. At this point, disease pressure is low and I have no CONFIRMED cases of tar spot; however, it is in central Nebraska so keep an eye out. Soybeans are making progress with early beans now flowering and shading the rows in 20-inch rows or narrower. Weed control is hit and miss on waterhemp, depending on size, when sprayed, and actively growing weeds. I’ve had reports of poor waterhemp control with a variety of herbicides. Herbicide injury calls the past two weeks have kept me busy. Pasture conditions are good in most places, and second cutting alfalfa is underway with some waterway hay being made now as well. The only insect issues right now appear to be Japanese beetles.”