Regional Crop Update: June 9 - June 16, 2025

Hail damage in parts of northern Iowa, herbicide injury, weeds not dying, true armyworms, and nutrient deficiencies were some of the more common issues 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. 

Leah Ten Napel (Region 1):

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

“Corn and soybean crops in NW Iowa are developing well. Many corn fields are starting to close canopies. Many post applications are being made to soybean fields. Little insect and disease pressure are being reported. Some herbicide claims are being worked through. Recent moisture and high temperatures are helping to move crop development along. Excess moisture in some areas has caused erosion or wash out issues. Pastures are growing nicely with our recent weather patterns. Northwest Iowa has received varying amounts of rainfall and some storm damage over the past week. Helpful resources for Hail on Corn and Hail on Soybeans can be found at these links. When making decisions on damaged fields it is important to compare the yield potential of the damaged crop vs. the yield potential of replanting. You must also take into consideration pesticides that have been applied to those fields. The resources previously listed do a great job of walking through that decision making process.”

Gentry Sorenson (Region 2): 

Buena Vista, Clay, Dickinson, Emmet, Hancock, Kossuth, Palo Alto, Pocahontas, Winnebago counties 

“Rainfall received was 0.3 to over 3 inches in region 2. The corn growth stage ranges from V4 to V8 due to varied planting dates. The soybean growth stage ranges from V3 to V4. Post emergence spraying of corn and soybeans was ongoing before the storms and rainfall. Corn was nearing completion of post emergence spraying and soybeans post emergence spraying was just beginning. Some soybean fields will need post emergence herbicide applications when field conditions allow. Quite a few fields of alfalfa were cut, with many able to be put up before the rain.  IDC is present in many soybean fields. On June11, large hail was received from north of Emmetsburg in Palo Alto County through Kossuth County near Fenton and south of Lone Rock. The hail continued north of Algona, south of Wesley, and then through Corwith and ending in an area south of Britt in Hancock County. Soybeans in many fields had severe defoliation and stem bruising. In corn fields, severe leaf removal was found and severe bruising along the stalks.  I would like to share the Hail on Corn in Iowa and Hail on Soybean in Iowa resources for those dealing with hail damage. Phone calls and field calls have been related to hail injury.” 

Angie Rieck-Hinz (Region 3):

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

“Rainfall across my counties for June 9-17 ranged from 1.34 inches at Fort Dodge to 2.98 at Mason City, with some localized reports of 6 inches near Plymouth over several rainfall events. Corn is V3 to V8 and soybeans are V2-V4. The table below is from the ISU Iowa Environmental Mesonet. Date range is April 10 through June 16.  You can see the rainfall reports as well as the Growing Degree Days (GDDs). The heat of this past week has definitely caused this crop to grow!  Iron chlorosis deficiency (IDC) is prevalent in our high pH soils. On June 11 we had widely scattered hail damage to crops across NW and NC Iowa. In some places, the hail caused severe damage to crops.  In the photo below, notice the deep stalk bruises and splits. Phone calls this week centered around herbicide tank contamination and the wrong herbicides applied on the wrong corn traits.” 

Terry Basol (Region 4): 

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

“In general, crops are looking really good for my area. Corn ranges from V2 up to V5 -V6 for most of the acres, and soybeans range from VC up to V3. The last couple of weeks have provided farmers nice field conditions to finish field operations, including side-dressing and post emerge herbicide applications. The corn that is the most mature, has really taken off, looking nice and dark green, as the nodal root system is now the primary root system. Along with that, corn canopy closure has begun in the early planted fields. For soybeans, first applications of post emerge herbicides have been conducted. Soybeans have had a slow start this season due to planting conditions and cooler weather, but with the warmer temperatures forecasted, they should catch up soon. In the realm of entomology, we are at peak egg hatch for corn rootworm. Research suggests about 50% of egg hatch occurs between 684-767 accumulated growing degree days (GDDs)(since January 1; base 52°F, soil), and according to the Iowa Mesonet, as of June 16, the Northeast Iowa Research Farm (NERF) has accumulated 705 GDDs. It is ideal to look at corn roots 10-14 days after peak egg hatch, or just after feeding is done (usually when you start to see adults in the area – roughly 4 weeks after peak egg hatch). As far as precipitation, we received some well needed rain events over the past couple of weeks. At NERF according to the Iowa Mesonet, for June 8 through June 14, NERF received 2.19 inches, with a cumulative total of 2.82 inches so far for the month of June. 

Josh Michel (Region 5): 

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

“In-between rain showers last week, producers continued post herbicide applications, fertilizer side-dressing applications, and finishing up the last remaining first harvest alfalfa fields. In general, most of the region received anywhere 0.50 to 1 inch of rainfall. Some isolated heavier amounts along the Minnesota border were as high as 1.5 inches, while some areas in Dubuque, Jones and Jackson Counties only received around 0.10 inch or less. Some of the early planted corn has quickly reached V5-V6, while the later planted corn is around V2-V3. Early planted soybeans have reached V3-V4, while later planted soybeans are generally around V1. I wouldn’t be too surprised to see the first flowers emerge by the end of the week on some of earlier planted soybeans. Applicators are reminded to check herbicide labels if soybeans have started flowering. Approximately 60% of the oats are starting to head out. The earliest-planted oats may start to turn by the end of the week as well. Alfalfa regrowth from first cutting appears to be doing well. Some producers may begin second cutting by this upcoming weekend if the weather holds out. Pastures continue to look good despite warming temperatures. 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 continues to receive rainfall, though pockets of my area have received very little in the last week and central Iowa overall has received lower than average rainfall for the last 30 days. Story County and parts of Polk County have generally been the winners of recent rainfall totals. Corn is advancing quickly, with many fields now a more even green color and closing the rows. I was in some V11 corn on June 17^th that was nearly as tall as me and very healthy. In general, the early planted corn seems more consistent than the later planting dates. A wide range of soybean growth stages exist on the landscape, from those planted in late May that are just now reaching V1 to those planted earlier in April that are V5 and nearly to R1. Many of the earlier corn issues have resolved themselves, but soybean issues persist – iron deficiency chlorosis, tank/boom contamination from corn herbicide products, uneven stands, etc. Keep an eye out in central Iowa for soybean gall midge, tar spot (and other corn foliar disease), and insect pest issues (corn rootworm, Japanese beetle) to start appearing in the next couple weeks. Weed issues continue to persist.”

Rebecca Vittetoe (Region 8): 

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

“In the last week, rainfall totals varied with areas no rain and parts of Jefferson and Poweshiek counties receiving at least 0.75 inch of rain. Both corn and soybeans fields have really grown over the last week. The earlier planted corn fields have canopied over and are in the V8 to V10 stage. Soybean fields range from V1 to V5. Late last week and here this week, I have been able to spot soybeans plants within soybean fields starting to flower. Issues or questions I’ve observed or have received in the last week include armyworms in corn and pastures, potassium deficiency showing up in corn and soybean fields, herbicide injury (drift, wrong product sprayed, tank contamination), and weed control concerns. Tar spot was found in Poweshiek County this last week, but the warmer temperatures this week will slow any tar spot that has started. You can check out the new Crop Risk Tool to assess the risk for tar spot in V0 to R3 corn. In general forages are looking good and some alfalfa fields are getting close to the second cutting.” 

Virgil Schmitt (Region 9):

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

“Most of the area I cover received no rain to 0.3 inch of rain during the last week. Most corn is V6 to V8 and generally looks good. Some fields have canopied over. Soybeans are mostly V3 to V5 and generally look good. I have not seen any blossoms yet, but I’m sure there are blossoms in some fields. Calls during the last week have mostly centered around weed management, herbicide injury, spray tank contamination, and herbicide drift.” 

Aaron Saeugling (Region 10): 

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

Corn made substantial progress last week and is looking better. Spotty showers over the past seven days have made corn jump in growth. Corn is developing a new leaf every 50 to 70 growing degree days (GDDs). Keep in mind that corn in the V6 stage is determining yield influencing factors like number of rows of kernels, this factor has a strong genetic influence, but herbicide injury, nutrient deficiencies, and soil moisture can affect this. Be careful with herbicide and foliar applications currently. Fields scheduled for over-the-top application of nitrogen can be seen with limited leaf burn. Soybeans continue to struggle with growth and development, mostly from environmental conditions and herbicide response. Soybeans will welcome the added heat and rainfall. Keep in mind that soybeans are more tolerant of hail damage now than corn. This is because corn at this growth stage is not likely to compensate for hail damage where soybeans can recover from leaf defoliation, provided the main stem is not damaged. Soybeans will begin to flower soon so when considering over the top applications of aggressive adjuvants, use caution. It is important to stage soybean prior to applications as well as watch weather conditions during application and expect crop response. Keep in mind the weed control is critical to maximizing yield in soybeans.” 

Logan McCrea (Region 11): 

Appanoose, Davis, Lucas, Mahaska, Marion, Monroe, Van Buren, Wapello, Wayne counties

“Rainfall for the past 7 days varies across my region, with the far western and far eastern areas of the region getting the most rainfall. Lots of early planted corn has closed canopy and all-in-all looks very good. Soybeans have been slow growing throughout the season thus far but seemed like some of the fields may have turned a corner towards the end of last week and finally started to make some noticeable progress. Almost all of the 1st cutting hay was wrapped up in the last week or so, with many of the early cut fields nearing 2^nd cutting with some good-looking regrowth. Pastures are hanging in there but would sure take a nice drink this week. Most notably, I received my first report of armyworm damage in a pasture last week, and some of the other field agronomists across the southern to central areas of Iowa have begun hearing about them as well so a good notice to keep an eye out for them!