Regional Crop Update June 11 to June 19 2018

Parts of Iowa received some much needed rainfall last week, but unfortunately for some areas the storms that rolled through also brought along hail and caused flooding. Overall, crops are looking good across the state with 84% of the Iowa corn crop and 80% of the soybeans crop being rated in the good to excellent condition based on Monday’s USDA Crop Progress Report. Iowa State University Extension and Outreach field agronomists report crop conditions in their respected regions.  

Northwest Iowa

Joel DeJong (Region 1): “The NW Corner of Iowa had a mixed week – some areas received almost no rainfall, and areas of O’Brien and Osceola County had many reports over 6” of rain. Localized flooding occurred due to that rainfall event. Areas that did not receive rain last week have already had a good rain early this week. For the most part, crops are looking very good, and the U2U growing degree model shows predicted silking for many fields before the middle of July – and some in early July. Soybeans at the NW Research have begun to bloom in the 4/30 and 5/7 planting date plots. There remain some yellow streaks in a few cornfields, some carry-over herbicide issues, and a few cases of herbicide drift. Watch weather conditions and understand the label before all herbicide applications!”

Soybeans planted on 4/30 and 5/7 are blooming at the NW IA Research Farm. Photo by Joel DeJong. 

Paul Kassel (Region 2): “Field work progress has come to an abrupt halt for much of my area. Recent rains have been excessive in parts of Pocahontas, Clay, Palo Alto, Dickinson and Emmet Counties. In contrast, there are areas in Sac and Buena Vista Counties that are dry – and have received only a couple of inches of rain in June. There are some corn fields that will not get their postemergence herbicide application – due to the recent windy weather, rainy weather, excessive rain, etc. There is also concern of the timeliness of the postemergence herbicide for the soybean crop. The pre-emergence products are working quite well.  However, it may be a challenge to be timely with fomesafen (10-month corn rotation restriction) and dicamba (weed size and potential for off target movement).”

Corn crop showing injury from a 2017 misapplication of fomesafen in Pocahontas County. Note that even the replanted corn is also showing injury symptoms. Photo by Paul Kassel. 

Northeast Iowa

Terry Basol (Region 4): “Corn and soybeans continue to develop rapidly in NE Iowa, given the warm temperatures and current soil moisture conditions for the past week. Corn is anywhere from V5 up to V8 – V9 and we are still seeing some fields that are showing signs of rapid-growth syndrome (pictured above). For more information on rapid growth syndrome, see the ICM article titled: Twisted whorls, buggy whipping, yellow leaves. In general, soybeans are anywhere from V3 up to R1 for most of NE Iowa, with postemerge herbicide applications occurring throughout the area within the last week. Oats in NE Iowa are 46 percent headed out according to the most recent Iowa Crop Progress & Condition report by the National Agricultural Statistics Service (NASS). Eighty-three percent of the oat crop statewide was rated in good to excellent condition.”

Corn field with plants showing symptoms of rapid growth syndrome in NE Iowa. Photo by Terry Basol. 

North Central Iowa

Angie Rieck-Hinz (Region 3): “The week of June 11 saw spotty to heavy rain across central to NC Iowa. Rainfall reports indicated amounts of 0.5 to 6 plus inches. While some areas received too much rain, the eastern most part of Story County, parts of Hardin and Marshall could use some rain. In areas with excessive rain, we have a lot of ponding and loss of crop in potholes and other places where the rain was so intense we experienced severe erosion washing out areas in fields. There are still areas in the northern regions that were planting soybeans last week. I have received several phone calls on herbicide carryover from 2017 as well as herbicide injury from tank contamination. On Friday (June 15) I looked at an armyworm infestation in a soybean field that had a cereal rye cover crop. The armyworms were not eating the soybeans, but were defoliating the bromegrass in the ditch and moving into the corn. This should be a reminder to anyone who had a cereal rye cover crop to scout for armyworms, not only in the soybean field but also adjacent corn fields. Armyworm will eat soybean, but prefer grass.” 

Southwest and West Central Iowa

Aaron Saeugling (Region 9):  “Corn is looking good as isolated showers have helped keep the corn growing. Herbicide applications and sidedressing nitrogen has basically wrapped up in corn. Currently, not seeing any major insect issues as of right now. Unfortunately, some areas experienced hail damage, but most of the corn is growing out of the damage. Heat and lack of rainfall will be the challenge in the coming weeks. While the corn is looking good, the soybeans have struggled a little bit more. We have had several issues this spring with soybean emergence due to herbicide issues, planting depth, diseases, and insect pressure. The focus this week in soybeans will be post emerge herbicide applications. My recommendation for farmers is to scout, scout and scout. Hay and pasture conditions are holding on right now. If you feel pasture may be short in the coming month either rotate pastures or supplement cows now to avoid overgrazing. A little supplement now will pay big dividends this fall for grazing and regrowth of pastures.”

Southeast and East Central Iowa:

Rebecca Vittetoe (Region 10) and Josh Michel (Region 11): “We received some much needed rainfall in parts of SC Iowa, which really helped the crops through the heat this past weekend. Rainfall ranged from three or four tenths to a couple of inches in areas. Corn is mostly in the V10 to V12 stages and soybeans are mostly V3 to V5 stages, with many fields already flowering (R1). Common issues, calls, and field visits last week included yellow and uneven corn, potassium deficiency showing up in corn, herbicide issues, and weed control challenges. It was not uncommon, especially on the really warm days, to see corn leaves rolling. Potato leaf hoppers were found at the ISU McNay Farm near Chariton in the alfalfa plots, so that is a good reminder to get out and scout for potato leaf hoppers. Another insect pest to keep an eye out for is Japanese Beetles as they have started to emerge. Just be careful not to be them confused with chafers, another beetle that at first glance is often mistaken for Japanese Beetles. Pastures and hay fields are hanging in there, but pond levels are really showing how dry we are in SC Iowa.”  

     
(Left photo)Take the time to scout your alfalfa fields for Potato Leafhoppers. (Right photo) Corn plants in a field just south of Centerville, IA on 6/15/18 showing signs of potassium deficiency and leaf rolling due to the dry conditions in this part of the state. Photos by: Rebecca Vittetoe. 

Virgil Schmitt (Region 8): “During the last week, in the counties I cover, areas roughly east of HWY I-380, HWY 281, and HWY 27 received less than 0.5 inch of rain while areas roughly west of that line received between 0.5 and 1.0 inch of rain. Oats are heading out. Corn is mostly V10 plus or minus one leaf, and it is generally in good condition. However, the corn has been showing signs of moisture stress during the hottest portions of the day. Soybeans are mostly V3 plus or minus a leaf. A few fields are at R1 and there are even some fields at R2. Soybean fields generally look good. Calls started last week on herbicide group 4 injury symptoms on soybeans as well as calls regarding waterhemp management.”

Rainfall totals across the state of Iowa for the past 7 days. Source: http://www.weather.gov.

Find your local ISU Extension and Outreach field agronomist here!