Regional Update: July 12 to July 20, 2021

July 20, 2021 9:52 PM
Blog Post

Corn started pollinating within the last week, and soybeans range from full flowering (R2) to beginning pod (R2). The hot topics this past week across the state included foliar fungicide decisions, corn rootworms, and herbicide injury in soybeans. Read on for more specifics on what ISU Extension field agronomists are hearing and seeing around the state.  

Northwest Iowa

Gentry Sorenson (Region 2): “Rain fell across much of the area last week, with rainfall totals right around 1 inch or just slightly less than 1 inch on July 14. Continued rainfall will be welcomed as fields dried quickly after the rain event last week. Corn is in the VT to R1 growth stage, with a majority of the fields at the R1 stage. Growers have called with questions on corn rootworm beetles, with corn rootworm beetles spotted on field visits. Continue to monitor fields through pollination and check for silk clipping.  Additional information on corn rootworm and other corn silk feeders can be found here.  Soybean insects were not spotted on field visits last week, and I have not received any calls with questions on soybean insects to date. Soybeans are at the R2 to R3 growth stage with most of the fields that I walked at the R2 stage. Soybean herbicide off-target field calls continued last week, with most of the calls coming from more of the eastern part of the area that I serve. Additional questions were related to corn and soybean fungicide application timing as well as insecticide application.”

North Central Iowa

Angie Rieck-Hinz (Region 3): “For the week of July 12 to July 19, the eastern part of my counties received some much-needed rainfall (yes, I know I sound like a broken record).  Eldora had 1.51 inches, and Iowa Falls had 1.08 inches of rain. The Webster City area remains dry and has received less than one inch of rain to date in July.  The crop stress is evident in both the corn and soybeans. The comment I hear most frequently is “I don’t know how this crop can look this decent with very little rain”. With that rain also came some mostly minor crop damage from the tornado that traveled from Stratford to the north and east of Jewell.  There is little to no disease pressure in corn and soybeans. Rootworm beetles are abundant in some areas. Take the time to dig roots and evaluate any feeding damage. Herbicide complaint calls continue."


Corn rootworm beetles seem abundant in some cornfields this year. Pictured above is a western corn rootworm beetle. Photo courtesy of Rebecca Vittetoe.

Northeast Iowa

Josh Michel (Region 5): “Most of NE Iowa received some much-needed rainfall throughout last week. Up to 3 inches fell in areas along Highway 20, while parts of Allamakee and Winneshiek Counties only received around 0.5 inch. This couldn’t have come at a better time as pollination is occurring in many cornfields and soybeans are starting to set on pods. Dry weather in the forecast should allow any remaining second harvest of alfalfa to get finished up. I’d also expect to start seeing oat harvest to begin this week. Recent rains and cooler than normal temperatures last week provided some relief to pastures, and many have greened up. The vast majority of recent field calls have centered around pesticide drift complaints and damage to soybean fields. Other field calls have included questions regarding alfalfa and small grain management as well as several questions pertaining to fungicide applications.”

Southwest Iowa

Aaron Saeugling (Region 10): “Rainfall was widespread last week with the usual variability based on location. Some high winds, hail, and heavy rain was reported.  Crop conditions continue to look excellent except for those areas hit with wind or hail damage. Corn is in the R1 to R2 stage and shows little disease pressure at this point. Isolated areas of corn rootworm feeding have been reported and adults are emerging now causing a few concerns on corn on corn acres. Soybeans also continue to improve with adequate rainfall and summertime temperatures moving growth along. Most soybeans are in the R1 to R3 stage. Insect activity in soybeans is mild compared to years past as of today.  Forage and alfalfa look short but have benefited from the needed rainfall. The second cutting is baled, and the third cutting is off and growing.  I have noticed leaf hopper burn in several fields, so this will be something to keep an eye on.”


Soybean plant setting pods in a SW Iowa field. Photo courtesy of Aaron Saeugling.

East Central, Southeast, and South Central Iowa  

Rebecca Vittetoe (Region 8): “This last week brought some more rain and even some storms with tornados to EC Iowa. Rainfall totals ranged from 0.2 to 2.5 or more inches. The heavier rainfall amounts were mainly south of I-80. I’ve heard reports of storm damage and tornado damage in some isolated areas in Benton, Linn, and Jones counties. Corn is mostly at VT to R1, and many corn fields are pollinating this week. I’ve noticed a little gray leaf spot in some corn fields, but overall disease pressure is low. While I've had many inquires on tar spot this last week, I have yet to see any myself in a cornfield. Corn rootworms have been the hot topic I've dealt with this past week. I'm seeing lots of root feeding in continuous corn fields and even some rotated fields. Take time to do some digging and evaluate your corn roots. Also, keep an eye out on silk clipping with the adult corn rootworms. Soybeans are mostly at R2 to R3.  I’ve seen minimal disease and insect issues in soybeans. Calls on herbicide injury in soybeans have also started to back-off this past week.”


Corn roots from a continous corn field with a range of corn rootworm feeding and purning. Take time to dig your roots and know what they look like. Photo courtesy of Rebecca Vittetoe.

Virgil Schmitt (Region 9): “Rainfall during the last week in the counties I cover was generally 0.5 to 3 inches, with the larger amounts generally south of I-80 and the smaller amounts generally north of I-80. In general, temperatures during the last week in the counties I cover were 1 to 3 degrees below normal. Corn is generally VT/R1 and soybeans are generally at R2 to R3. There are few insect or disease problems currently. Most oats fields are turning or have turned color. I have not seen any harvested yet, but harvest should start soon.  Katydids are “singing” and there are a few winged grasshoppers. Calls and farm visits last week mostly involved herbicide drift, fungicide applications, hail damage to corn and soybean, and corn rootworms.”


Rainfall totals across the state from July 12 to July 18, 2021. Source: Source: https://mrcc.illinois.edu/CLIMATE/Maps/stnMap_btd2.jsp.

Clarabell Knapp (Region 11): “Pop-up shower systems scattered the region over the past week. Rainfall totals ranaged from a couple tenths to some areas getting 4 inches. Crops are looking good considering the cooler temperatures and wet conditions we have had. Most corn is in the VT or R1 stage and pollination is going well. Soybean fields are staged at R2 to nearly R3 for most of the area. There have been a lot of aerial applications of fungicides and top dress urea being made. Japanese beetles are continuing to be seen throughout fields. Small grain harvest will be looking to take place in the next week or two, though some fields were harvested before the last system of rains came through. The extended forecast is looking at warmer temperatures with low chances of precipitation. Many growers are looking to work on second cuttings for hay and alfalfa fields. Despite the consistent precipitation, disease pressure is seemingly low in both corn and soybeans."

Check out the map below to find your local ISU Extension field agronomist and find their contact information here!

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Rebecca Vittetoe Field Agronomist in EC Iowa

Rebecca Vittetoe is an extension field agronomist in east central Iowa. Educational programs are available for farmers, agribusiness, pesticide applicators, and certified crop advisors.

Areas of expertise include agronomy, field crop production and management of corn, soybeans, and...