Crop Update June 19 - June 27, 2017

Despite June typically being one of the wettest months of the year, it is ending to be much drier than normal across much of the state. Besides drier conditions, other common issues showing up in Iowa crop fields include weed management concerns, herbicide drift, nutrient deficiencies, and insects such as Japanese beetles and thistle caterpillars. Iowa State University Extension and Outreach field agronomists give a quick update on what's happening in their respected regions around the state.  

Northwest Iowa

Joel DeJong (Region 1): "The newest drought monitor does a pretty good job of letting you know what is happening in NW Iowa. Much of the NW corner is well below normal for rainfall in the past thirty days – during the month when we normally average the highest amount of precipitation for the year. There are actually a few fields where soybeans are still laying in dry soil, and others where corn roots aren’t getting established deep enough to get into the subsoil moisture that is still present. But, most fields are hanging in there quite well, and would benefit from a good rain. Herbicide applications have been pretty timely, since almost every day is dry enough to get into the field. Soybeans are beginning to bloom. Otherwise, no majors trends in crop problems at this point in time."

Some of the more extreme problem areas can be seen in this map which shows a percent of normal rainfall for the last 30 days. Source: weather.gov. 

Paul Kassel (Region 2): “Crop conditions continue to look good across my area. Scattered rainfall occurred last week. However, most of my area has had a scant 1 to 2 inches of rainfall since June 1, which is almost 3 inches below normal for some locations. This is one of the driest Junes in recent memory for many farmers. The dry weather has not caused any problems so far – with one major exception. The soybean crop that was planted May 26 to June 1 has had some real stand establishment problems. Some of that soybean crop has emerged recently while some of it dried out before emergence. Early May planted corn is in the V11 stage and the mid-May planted soybean crop is in the V3 stage.The Useful to Usable website predicts a 103 day hybrid that was planted on May 7 near Spencer will silk on July 25 – which is 5 days behind normal. Farmers are completing post-emergence application of herbicides to soybean fields. Waterhemp, giant ragweed and marestail are the most common weeds in soybean fields that farmers need to manage."

Giant ragweed four days after application of 22 oz/acre of Xtendimax and 32 oz/acre of PowerMax in Buena Vista county. Photo by Paul Kassel. 

Uneven soybean emergence of May 28 planted soybeans in Clay county. Photo by Paul Kassel. 

Northcentral Iowa 

Angie Rieck-Hinz (Region 3): "We have corn from V5 to V11 and soybeans from V2-R1. I have found a few soybean aphids, but nothing that warrants treatment. I have had nearly weekly hail calls from scattered hail across north central Iowa in multiple events. Some hail damage severe enough to completely destroy crop to most events that left corn tattered to beans with various damage from dead to shooting new axillary buds. Rain continues to be extremely spotty. The far western area of my territory- NW Calhoun County is the driest area, and while the Eldora area had been the driest, it is now on only 1.84 inches behind average rainfall for June 1 to June 26. Field calls in the past week include some herbicide drift complaints, herbicide injury, continued calls on rootless corn and a few calls on Palmer amaranth identification."

Northeast Iowa

Terry Basol (Region 4): “As far as crops go, corn is looking good in the area, ranging from V6 to V8. Soybeans are about V1 to V4, with many of the acres getting sprayed with the first post herbicide application this week. According to the Iowa Mesonet, we received 1.85 inches of rain last week between the dates of June 18 and June 25 here at the Northeast Iowa Research and Demonstration Farm. The second cutting of hay is also underway or will soon begin for this area of NE Iowa."

Central Iowa

Mark Johnson (Region 7): “Overall, much of the corn and soybean look very good considering the environmental conditions. The fields planted into less than ideal conditions or spots of fields that were too wet at planting are still looking less than ideal. I saw R1 soybean fields early to mid week last week. Last week, I went on several hail calls. Some of the fields I visited had small stand loss, but most had very little stand loss and will come out of it without severe yield loss. In some of the fields, when splitting stalks vertically down through the nodal roots, there are areas of brown, indicating stalk and root rot has begun and may spread later if there is stress at kernel fill time."

Southeast and South Central: 

Rebecca Vittetoe (Region 8): “Some of my counties received some much needed rain and others missed out on the rain. SE Iowa did appear on the US Drought monitor last week as being "abnormally dry." Corn, soybeans, pastures, and alfalfa could also use a good shot of rain. Most corn is V10 to V12 and soybeans range from replanted to R1. Most alfalfa fields are ready for the second cutting. Oats are starting to head out, and the few wheat fields in the area are getting close to harvest.  Common issues from this past week included hail damage to crops, compaction issues, potassium (K) deficiency showing up in corn fields, thistle caterpillar in soybeans, and weed control concerns." 

No one was home, but I did see the typical frass pellets and webbing created by the thistle caterpillar. Photo by: Rebecca Vittetoe.

Meaghan Anderson (Region 9): “Most areas of east central Iowa received a half inch of rain in the last week, but we're still at least 2 inches below the climate average in most areas. In fact, most of this part of the state is showing up on the drought monitor as abnormally dry now.  Corn is mostly in the V10-V13 range, while soybeans range from just replanted (still!) to R1.  With rains expected this week, farmers are quickly finishing up herbicide applications before they're rained out of the fields. Marestail (Conyza canadensis) continues to plague some fields above soybeans. Now is a great time to dig some roots and check for corn rootworm feeding, especially in continuous corn fields. It's also a good time to keep an eye out for Palmer amaranth while scouting." 

Palmer amaranth found in a soybean field this year. Photo by Meaghan Anderson. 

Virgil Schmitt (Region 10): “During the last week, most of the area received between 0.5 and 1.5 inches of rain. Several small hail storms occurred. I wasn’t aware of it last Monday, but a severe hail storm about 2-3 miles wide and 6 miles long hit west of Muscatine on Saturday night, June 17. Oats are heading out and harvest of the second cutting of hay has begun. Corn is mostly V10 to V12 and soybeans V4 to R1. Hail, lack of weed control, herbicide injury, sulfur (S) and potassium (K) deficiencies, Japanese beetles were common issues last week. It was noted in areas with hail that the Japanese beetles really liked new growth."

Map showing rainfall totals for Iowa over the last week. Source: http://www.weather.gov.  

Find your local ISU Extension and Outreach field agronomist here!