Regional Update: June 21 to June 29, 2021

June 29, 2021 10:35 PM
Blog Post

While some much-needed rain did come this past week it seems that the drier areas continue to miss out or get minimal rainfall and the wetter parts of the state keep getting wetter. The rain also brought some hail, which caused some pretty significant damage not just to crops but property as well. In addition to the rain (lack of, too much, or just enough) and hail, herbicide injury in soybeans and potassium (K) deficiency are some of the issues ISU Extension field agronomists have observed this past week. Read on to see what's happening in different regions across the state.

Northwest Iowa

Joel DeJong (Region 1): “An inch or more of rain fell in the southern half of the area I serve during the past week, with a few scattered neighborhoods getting up to 3 inches. This was much needed. The area to the north received less, and likely needs it more. From 0.2 to a half inch might have been more common there. Corn is V10, plus or minus two leaves. Soybeans V5 to V7 – most beginning to bloom (R1, some R2). Saw some K deficiency in a few fields this week – likely due to the inability to take up the nutrients under this environment, more than a case of low soil tests. Cupping is very visible on a lot of fields at this time, and most are uniformly injured across the entire field. A hailstorm last Tuesday evening left over 30,000 acres damaged, with a high percent totaled, mostly in Plymouth County. Some wind damage occurred on Thursday evening in counties to the south, but most appear to be recovering from this event.”

A corn field in Plymouth County that was totaled after the hailstorm that came last Tuesday evening. Photo courtesy of Joel DeJong.

Paul Kassel (Region 2): “​The dry weather continues.  Parts of Sac, Buena Vista, Pocahontas, and Hancock counties received some decent rainfall with amounts of over 2.0 inches over the weekend.  However, parts of Dickinson, Clay, Emmet, Palo Alto, Kossuth, and Winnebago remain dry. The weather station near Estherville in Emmet county has received 0.14 inches for the month of June. The weather stations at Milford, Spencer and Forest City have received less than 1.5 inches of rain since June 1. Crop production issues include dicamba vapor drift effects on non-dicamba soybean varieties. Soybean fields with non-dicamba varieties often show dicamba injury symptoms over the entire field. The dicamba vapor drift appears to have originated from Diflexx or Status herbicide application to corn fields since the symptoms appeared before dicamba was applied in soybean fields.”

Dicamba injury symptoms appear on a non-dicamba tolerant variety (left) in this soybean variety comparison plot. Photo courtesy of Paul Kassel.

Northeast Iowa

Terry Basol (Region 4): “Most of the corn and soybeans in NE Iowa range from the V8 to V10 and V4 to R1 growth stage, respectively. Potassium deficiency is showing up in both corn and soybeans due to the continued drought conditions. We see this in dry growing seasons, as dry soil reduces K uptake by slowing the movement of K from the soil solution to the plant root. Thus, K deficiency will occur in a dry year at higher soil test levels than will occur in a wet year. For more information, please check out a couple of ICM articles on the topic here and here. Also, keep an eye out for defoliating pests like grasshoppers and Japanese beetles in both corn and soybeans. I have seen some beginning activity of grasshoppers in the area. Currently they are small nymphs but continue to scout and monitor their feeding activity if the dry weather conditions persist. Oats are beginning to turn. Parts of the area were blessed with rainfall this past weekend starting Friday night (June 25th). According to the National Weather Service, the area I cover received anywhere from 0.5 to 4.0 inches, with isolated areas receiving an excess of 5 inches. The NE Iowa Research and Demonstration Farm near Nashua received 0.5 inches over the weekend. In general, my northern counties received the greatest rainfall.”

K deficiency symptoms are yellowing to necrosis (tissue death) of the outer leaf margins on the lower leaves. These symptoms begin at the leaf tip and progress down the margin toward the leaf base. Photo courtesy of Terry Bassol.

Josh Michel (Region 5): “Most of NE Iowa has received some much-needed rainfall after several storm systems have come through the area. Combined precipitation over the last week has resulted in areas along Hwy 20 receiving around 0.5 inch of rainfall, while some areas in Allamakee and Clayton counties received up to 3 inches. Unfortunately, there was some severe weather that impacted the region. Flash flooding occurred in the immediate area around Marquette as they received around 6 inches of rainfall within a short time period. There was also some crop damage in southern Buchanan and Delaware counties as hail and strong winds came through that area. Thankfully the rainfall, along with some cooler night temperatures, did manage to bring some relief to crops that had been showing signs of heat stress. Corn is generally around V9 and continues to grow very quickly. Soybeans are generally from V4 to R1, as some early planted fields are just beginning to flower. Alfalfa second crop is taking advantage of the recent rainfall and growing nicely. I would expect second crop harvest to begin by the end of the week as fields begin to dry out. Oats continue to do well. Around 90 percent of the fields are headed out, with around 15 percent turning color. Pastures have rebounded slightly as they have also taken advantage of recent precipitation and cooler temperatures. Recent field calls and questions have centered on managing alfalfa and oats as well as handling several calls pertaining to pesticide drift complaints.”

Southwest Iowa

Aaron Saeugling (Region 10): “Most of SW Iowa received some rainfall over the past week, with some locations getting over 3 inches with hail in pockets. The pockets with hail, in some cases I expect a significant loss on corn and some soybeans. Corn looks good and is in the late vegetative stages from V10 to V14. It should not be long before some tassels start to appear in fields. Soybeans are also looking good with most herbicide applications finishing up. Soybeans are in the V4 to V5 stage and are beginning to flower. I’ve had field calls on herbicide issues and difficult planting conditions in some locations.  Forages look good considering the lack of rainfall in most arears in May and early June. The rainfall has brough some pastures back to life and second cutting alfalfa should be better than previously expected. On the insect front, we are finding soybean gall midge across Pottawattamie and Cass counties so far, and some light Japanese beetle pressure has begun.”  

Central Iowa

Meaghan Anderson (Region 7): "Central Iowa received nice rainfall in the last week and crops are looking much better with the cooler conditions and rain. We’ll need it to continue, so I’ll be watching the forecast. I haven’t gotten many phone calls about corn as it is greener and looking much better than it did early in the season. I received my first image of potassium deficiency in corn (yellowing of lower leaf edges) and corn rootworms are a hot topic of discussion. We did get some isolated hail in parts of Dallas, Polk, and Warren counties in the last week that shredded corn leaves and completely defoliated some soybean fields. Soybeans are mostly in the R1 to R2 stage and phone calls have continued to focus on herbicide injury and other issues in soybean."

Hail damage in a Dallas County corn field. Photo courtesy of Meaghan Anderson.

East Central, Southeast, and South Central Iowa  

Rebecca Vittetoe (Region 8): “We’ve gone from hot and dry to being cooler and soogier this past week here in EC Iowa. Rainfall totals over this last week ranged from 0.5 to 5 or more inches. The rain also brought some hail with it to northern Linn and Benton counties and also right around the Keokuk, Jefferson, and Wapello county lines. Damage from the hail included defoliation, bruising (stems and stalks), and even stand loss. Fields with less severe damage seem to be recovering well, but some fields suffered some pretty significant damage. Corn is around the V10 to V14 stage and soybeans are starting to reach the reproductive stages. Topics of discussion or concern this past week in addition to the hail damage included corn rootworm, weed management, and herbicide injury in soybean fields.”

Virgil Schmitt (Region 9): “Rainfall during the last week in the counties I cover was generally 1 to 2 inches north of I-80 and 2 to 3 inches south of I-80, with over 4 inches in the Mount Pleasant area. In general, temperatures during the last week in the counties I cover were 1 to 4 degrees below normal. Corn is V11 +/- one collar and soybeans are generally about R2. European Corn Borer (ECB) shot holing started last week. Calls last week centered mostly around ECB management on corn without above-ground Bt traits, herbicide efficacy, herbicide selection, and herbicide drift."

Rainfall totals across the state of Iowa from June 21 to June 27, 2021. Source: Source:

Clarabell Probasco (Region 11): “In the past week, much of the area has received an abundance of rainfall, on average ranging from 4 to 5 inches, and some areas reaching up to 8 inches. Much of this rain came with strong winds and unfortunately some with hail. Some corn fields began to lean with the wind but were able to stand back up a day or two later. The hail damaged crops have been able to begin new growth and will be watched closely to see how they continue to grow. Attached are a few pictures of some of the hail damaged fields near Packwood. The before pictures were taken three days after the hail event and the after pictures were taken 6 days after the hail event. There is good regrowth seen on the soybeans as well as healthy leaves continuing to come out of the whorl on the corn plants. Corn fields are around the V12 stage and soybeans are typically seen around V8/R1 stages. Pastures and forages have been able to benefit from the continued rain and cooler temperatures. Field calls have been done in regard to wind and hail damage and weed control and identification.”

The corn and soybean fields with the hail damage from last Tuesday night's hailstorm. Photos on the left were taken 3 days after the hailstorm and the photos on the right were taken 6 days after. Photos courtesy of Clarabell Probasco.

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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...