Regional Crop Update: May 18 - May 27, 2020

May 27, 2020 3:33 PM
Blog Post

Last week brought little sunshine, cooler temperatures, and soggy conditions across much of the state. Yellow-looking corn, slow growing crops and forages, and uneven or poor stand establishment were some of the common concerns ISU Extension field agronomists have been hearing and seeing. Read on for more information about what’s happening in specific regions across the state.   

Northwest Iowa

Joel DeJong (Region 1): “The NW corner of Iowa has had a cool, cloudy week. The weather stations I monitor in the region are between about 55 to 90 GDD’s behind normal since April 20. Solar radiation data looks to be about 15% less than normal since then as well. Rainfall compared to average is one to two inches behind normal, but this weekend brought about an inch to the region, giving us good soil conditions to get the crop growing rapidly when it warms up and the sun shines again. Most corn I have observed ranges from V2 to V4. Many soybeans are now emerged, but a few acres are left to plant. A Plymouth County alfalfa field I walked this morning (Tuesday, May 26) was now 29 inches tall and buds can be seen. The RFV was down to 160, and the field was starting to lodge. I believe it will be harvested when it dries out a little later in the week.”

Paul Kassel (Region 2): “This week has been another quiet week with almost no field work in my area. There were some heavy rains the week of May 17, and there has been more rainfall since then. As a result, we have a lot of really wet fields and water standing in a lot of fields. We will have some replanting of corn and soybean crops as a result of this continued rainfall. Farmers and agronomists are encouraged to check fields for black cutworm damage despite the light black cutworm moth flights observed in this part of the state. The recent cool weather has slowed corn development, which will make corn more susceptible to black cutworm damage for a longer time period.”  

Dry and dusty conditions have changed to cool and wet conditions across parts of Iowa. Photo courtesy of Paul Kassel.

North Central Iowa

Angie Rieck-Hinz (Region 3): “From May 18 to May 26, we experienced 1.13 inches (Humboldt) to 2.86 inches (Iowa Falls) of rain. The rains of the past week have brought our yearly totals for precipitation back in line with the long-term average; however, Hampton is still averaging 1.78 inches below normal. Oddly, parts of Calhoun, Webster, Hardin and all of Hamilton, Wright, Franklin Cerro Gordo and Worth show up as D0 or abnormally dry on the U.S. Drought Monitor.  I would anticipate that to change with this week’s report. Prior to the rain some post-emerge herbicide had gone on in corn and now people are concerned about when they can return to the field to side-dress nitrogen.”

Central Iowa

Meaghan Anderson (Region 7):  “The last week brought more overcast skies and rain to central Iowa. I think we have a Goldilocks situation where some areas are getting too much, but ponds are still relatively nonexistent in many areas where we see them in a typical year. Most corn is emerged and in the V2 to V3 growth stage, while most soybeans are at VE. Stands look good overall, but some fields have a lot of unevenness to stands. I had my first report of black cutworms on May 26, so be out looking for them while scouting, along with other prevalent issues like white grubs and weeds. Phone calls in the last week we’re about weed identifications, uneven corn stands, herbicide programs for corn and soybean, and soybean emergence issues.”

Evaluating a stand of corn in Central Iowa and insepecting why some corn plants never emerged. Photo courtesy of Meaghan Anderson.


True white grubs found in a corn field in Central Iowa. Photo courtesy of Meaghan Anderson.


Aaron Saeugling (Region 10): “ Little field work was completed last week due to moist conditions. Corn is emerging and growing but with the lack of sunshine has a yellow color. Most corn is V1 to some of the early planted corn being at V3. Soybeans have also been slow. Reports of alfalfa weevil infestations are common south of Hwy 34. Most growers are waiting to cut first crop alfalfa to stop alfalfa weevils. Spraying is the big challenge with wet fields, cool temps, and windy conditions. Overall planting went very well compared to recent past years; however, crops are just a little slower than we all would like for late May.” 

East Central, Southeast, and South Central:

Rebecca Vittetoe (Region 8): “The sun finally decided to make an appearance over this past weekend after a gloomy and cooler last week. Rainfall has been spotty this last week with some areas receiving just a few tenths to other areas getting closer to an inch of rain. Corn ranges from V1 to V3. Last week the corn was looking pretty yellow, but it has really started to green-up in the last couple of days and take off with the warmer and sunnier weather we experienced. Some farmers have started to sidedress corn. Soybeans are mainly VE or VC. I have seen and received calls about soybean stands being more uneven and less than ideal in some areas. For insect pests, be keeping your eyes open for black cutworms, alfalfa weevil, and bean leaf beetles. Also, be scouting fields for weed pressure. I’ve seen a lot of little weed seedlings making their appearance in fields, especially waterhemp. Stand assessment, weed management, slow forage growth, and yellow-looking crops were common questions and concerns this past week.”  

Virgil Schmitt (Region 9): “In general, rainfall last week in the counties I cover was less than half an inch south of Highway 30 and between a half to one inch north of Hwy 30. Additionally, temperatures last week in the counties I cover were near normal to two or three degrees cooler than normal generally south of I-80 and near normal to one to two degrees above normal north of I-80. Corn planting is nearly complete. Most fields are at V1 to V3 and look good. I am receiving scattered reports of minor black cutworm activity south of I-80. I expect more reports to be starting to come in north if I-80 this week. Additional information on scouting for black cutworm can be found here. Soybean planting is also nearly complete, and soybeans are mostly VE to VC. Overall, soybeans look good. Lightening bugs are beginning to flash and black flies are being a nuisance. Herbicides, herbicide drift, nozzle selection, and soybean replant decisions dominated calls last week.”




Josh Michel (Region 11): ““Most of my region has received anywhere from 0.25 up to one inch of rainfall over the past seven days. Although severe weather impacted much of the area, there haven’t been any reports of crop damage. Breaks between rain showers did allow for some fieldwork to take place. Planting progress estimates have slightly increased to 90-95% of the corn acres are planted and 80-85% of the soybean acres are planted. April planted corn is generally V2 to V3, while April planted soybeans are V1 to V2. Warmer temperatures and adequate soil moisture have greatly helped seedling emergence. Stand assessments are still being conducted in some areas that received higher amounts of rainfall over the past two weeks. Pasture conditions continue to improve. Many alfalfa fields are nearing the first cutting, pending favorable weather. Recent field call questions have included pasture management, alfalfa weevil management, corn and soybean stand assessments and replanting, weed identification and post herbicide applications.”

Frost damage and wet soils were causing some stand concerns in this corn field in Davis County. Photo courtesy of Josh Michel.

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


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...