Regional Crop Update: June 2 - 9, 2025

With many corn fields across the state reaching that V5 to V9 growth stage, they are getting a dark deep color and rows in some fields are getting close to canopying. Soybeans in general seem a little slower this year and could really use some sunshine and heat. Herbicide injury, weeds not dying, IDC in soybeans, and Rapid Growth Syndrome in corn were some of the issues or concerns heard or seen by ISU Extension field agronomists this last week. Read on for more specifics about what is happening across the state from your local ISU Extension and Outreach field agronomists. 

Josh Michel (Region 5): 

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

“Post herbicide applications, fertilizer side-dressing applications, and completing first cutting alfalfa harvest were the main field activities across the region last week. Thankfully, we were also able to receive some much-needed rainfall. While most of the area received 0.25 to 0.50 inch of rainfall, some isolated areas near the Minnesota border received around 1 inch of precipitation. In general, I’d say most of the crops are looking good to excellent, at this time. Some of the early planted corn has quickly reached V4-V5, while the later planted corn is around V1-V2. Early planted soybeans have reached V2-V3, while later planted soybeans are generally around V1. Approximately 40% of the oats are starting to head out. Alfalfa regrowth from first cutting appears to be doing well, but producers should continue to keep an eye out for any increases in insect pressure. Pastures continue to look good and anticipated rainfall this week should keep them going strong. The majority of field calls this past week centered around weed identification and management, adjusting herbicide programs, 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 received rainfall in the last week; most areas received less than 1 inch while some topped over 2 inches for the week. With the heat coming this week, our crops will appreciate the moisture, and this agronomist is already looking at the forecast to determine when the next rain chance might be. Corn is evening out in color and looks much better than it did a couple weeks ago, though I’m still fielding calls about uneven corn, anhydrous ammonia burn, herbicide drift, tank contamination, and the occasional insect issue. Soybeans are beginning to emerge from their “ugly duckling” phase as well, with some of the largest soybeans in the V3-V4 stage. Postemergence herbicide applications in both corn and soybean are starting to wrap up in many fields and these hot conditions coming this week should reveal what herbicides are working well vs. which fields may need a respray. We’re approaching the point in the growing season where rows start to close and herbicide applications cease, but this opens up fields to new issues we need to monitor for like tar spot and corn rootworm in corn and soybean gall midge, Japanese beetles, and foliar disease in soybean. Keep scouting!”

Rebecca Vittetoe (Region 8):

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

“Over the last 7 days (June 2 through June 9), rainfall totals really varied in my region with just a couple tenths of rain in Poweshiek and Iowa counties to over 1.5 inches in Jefferson County. Corn is getting a nice dark green color and overall looks pretty good; however, I’ve had several questions on random yellow leaves salt and peppered throughout cornfields, which is known as Rapid Growth Syndrome. In general, soybeans look ok, but there are a lot of more pale-green or yellowish looking fields, which is likely contributed to the cooler and cloudy conditions we’ve had recently. Field actives over the last week have included sidedressing corn, postemergence herbicide applications in both corn and soybeans, and putting up first cutting hay. Herbicide drift/injury as well as weed identification and management were common questions or issues that came up last week. A more unique question this last week was on a soybean field with phytophthora.  When scouting, keep your eyes open for how well weeds are dying from herbicide applications, potential pests like Japanese beetles, SCN in soybeans, and corn rootworm larvae being present in fields.” 

Virgil Schmitt (Region 9):

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

“Most of the area I cover received 0.5 to 2.0 inches of rain during the last week. Most corn is V5 to V7, and generally looks good. Some fields will canopy over this week. Soybeans are mostly V1to V3 and generally look good.Poison hemlock and musk thistles are starting to bloom. Calls during the last week have mostly centered around weed management, herbicide injury, and herbicide drift.”

Aaron Saeugling (Region 10):

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

“Crop conditions vary across SW Iowa this season. However, there is one common theme—poor looking soybean fields. This is caused from factors like herbicides and the cool conditions. Monther Nature is always in charge and takes the blame for poor looking crops. Soybeans require heat and sunlight to elongate and both of those have been below average for the month of May. The good news is we did receive needed rainfall and warmer weather is forecasted. With the warmer temperatures, expect weed pressure to continue and progress as fast as soybeans grow. Corn looks better than soybeans currently. Herbicide injury and rapid growth syndrome are the issues seen currently. Corn is closing the canopy on the early planted fields, which have hit that critical V6 to V8 stage, which is when the ear shoots are being formed. Be cautious with herbicide applications and weather conditions at this stage of crop development.”