End of August Crop Update for East-Central, Southeast, and South-Central Iowa

Check out what ISU Extension and Outreach field agronomists in EC, SE, and SC Iowa are seeing and hearing in their areas regarding crop progress and issues showing up in crop fields.

Rebecca Vittetoe (Benton, Iowa, Johnson, Jones, Keokuk, Linn, Mahaska, Marion, Poweshiek, and Washington Counties): “Over the last two weeks, we’ve caught some much-needed rain in this part of the state with rainfall totals ranging anywhere from about 1 inch up to 5 inches or more in some areas. From a crop maturity perspective, corn ranges from R3 to R5 and soybeans are mostly R5. Tar spot has been found in several corn fields in Iowa again this year. At this point there is not much we can do other than making note of where it is at. If you suspect that you have Tar Spot, please reach out or send a sample in to the Plant and Insect Diagnostic Clinic. We are collecting samples for research. I’ve noticed and have gotten quite a few calls regarding yellowing in soybean fields. A lot of what I have seen looks like potassium deficiency, but I have seen a few fields that the yellowing looks more like top dieback.”

Virgil Schmitt (Cedar, Clinton, Des Moines, Henry, Jackson, Lee, Louisa, Muscatine, and Scott Counties): “Rainfall the last two weeks ranged anywhere from 1 to 5 inches in my area. Corn ranges from R3 (June planted corn) to R5 (April planted corn). The R5 corn is about 0.5 milk line. Soybeans are mostly R5. Group 4 injury calls are continuing. Potassium deficiency and/or top die back is showing up in a few fields. Pastures are starting to recover. Inquiries about and Group 4 and group 15 herbicide injury on soybeans dominated calls last week. Weed escapes and late-summer forage seeding were also common calls.”

Josh Michel (Appanoose, Davis, Lucas, Jefferson, Monroe, Van Buren, Wapello, and Wayne Counties): “Widespread rain showers brought over an inch of rain to much of SC/SE Iowa last week, with heavier amounts up to three and half inches in some areas. Pastures and hayfields are greatly benefiting from the precipitation and cooler temperatures. April planted corn is generally around R5 and looking good. The later June planted June corn is around R2 to R3. Early planted soybeans are mostly around R5 to R6, while late planted soybeans are generally around R2 to R3. Common field calls and questions have included foliar diseases in corn (common rust, gray leaf spot and northern leaf blight), fall stalk nitrate testing, third generation thistle caterpillars, late season weed escapes, and herbicide injury in soybeans.”

Find your local ISU Extension and Outreach field agronomist here!