Regional Crop Update: May 11 - May 19, 2020

May 19, 2020 9:20 PM
Blog Post

Some much-welcomed rain fell across the state this past week. Prior to the rain, farmers continued to make progress on getting the crop in the ground. According to the May 17th USDA Crop Progress Report, 96% of Iowa’s corn crop has been planted and 86% of the soybean crop has been planted. Common concerns ISU Extension and Outreach field agronomists encountered this past week included crop recovery from the frost and slow emerging and yellow-looking crops. Read on to see what's happening in specific areas across the state.  

Northwest Iowa

Joel DeJong (Region 1): “In the NW corner of Iowa, it seems that almost all of the corn is emerged. Although cool temperatures and cloudy days have kept these plants from looking as green as we want, they do appear healthy, and stands are pretty good. This past weekend most of the region got at least a half inch of rainfall, with many receiving about an inch. It was needed. Soybeans are nearly all planted and about half are emerged. They, too, could use warmer, sunnier weather. We have had enough dry days to stay current on getting pre herbicides applied but have had to put off going after post treatments for corn because of slow crop and weed growth. Alfalfa is slowly growing, with a field I was in on Monday measuring 21 inches tall, and still in the vegetative stage. With some warmth this will take off and start budding soon. The relative feed value (RFV) of this field would be just over 200 at this time. I did not find alfalfa weevils, but it is time to scout carefully for this pest.”

West Central

Mike Witt (Region 6): “The rain received across WC Iowa this week was much needed. Areas of the region had slipped into the US Drought monitor at the D0 or Abnormally Dry classification. This classification is the lowest on the scale and should be taken as a sign that the soil in the area is dry, in need of moisture and is something to monitor. Corn across the region is in the VE to V2 stage and moving slowly. WC Iowa is around 50 to 75 GDU (growing degree units) behind the average for this time of year, depending on planting date. These cool temperatures and the moisture profile have led to crops developing at a slower pace. This is not a cause for great alarm as a little rain and warm temperatures will help perk up the corn. However, it is going to not be the prettiest looking corn for a while across the area. Soybeans are starting to emerge as well but are also feeling the effects of cooler temperatures. Weed pressure across the area is sporadic as many fields received their pre emergence programs and are waiting on growth of crops for post emergence applications. Herbicide effectiveness has been mixed with the cooler temperatures and weed growth but only patience and time will show you how effective your choices have been. This week when scouting, look for stand issues in emerging crops and evaluate what type of weed pressure are you starting to see. Alfalfa and pastures are also moving along at a slower pace but should see budding stages and first cutting approaching in the near future.”

Alfalfa at the Western Research Farm measuring 18 inches tall on May 19th. Photo courtesy of Chris Beedle.

Central Iowa

Meaghan Anderson (Region 7): “Central Iowa received some much needed rainfall over the weekend, with most areas receiving near an inch, but Warren County caught more rain than most other areas across my region. Most of central Iowa is more than 60 growing degree days (GDDs) behind normal since April 15th, so despite the quick start and finish to planting, crops are slowly (but surely) coming out of the ground and putting on leaves. Calls and texts in the past week were mainly about recovery from frost injury, corn emergence and yellow color, weed identifications, and hay/pasture weed management and soil fertility. As many crops have emerged, don’t forget to do stand assessments in both corn and soybean as a ‘quality control check’ for the crops to determine what their actual stand is compared with what was planted.”

An early planted corn field showing some uneven emergence and a little frost damage on the leaves. Photo courtesy of Meaghan Anderson. 

East Central, Southeast, and South Central:

Rebecca Vittetoe (Region 8): “Rainfall totals seemed to range from a half inch to three plus inches across EC Iowa. Planting is winding down in this part of the state. Corn ranges mainly from VE to V2 and soybeans range from recently planted to VE or VC. Overall, it appears that the crops are recovering from the frost that took place on May 9. Some of the soybeans that were emerged when that frost event took place did not make it. Take time to scout and assess how stands are looking. Now is the time to start scouting for black cutworms, check weed pressure, and to continue to scout for alfalfa weevils. I’ve seen a few alfalfa weevil larvae in alfalfa. Common calls and questions over the past week focused on frost injury, weed management, pasture management, yellow-looking crops, and early season scouting considerations.”

Take time to assess stands as crops emerge and also check on weed pressure. Waterhemp is starting to makes is appearance in fields. Photo courtesy of Rebecca Vittetoe.

Virgil Schmitt (Region 9): “Most areas in the counties I cover received two to three inches of rain in the last week, with some spots receiving over three inches and some spots receiving just a little under two inches. Corn planting is nearly complete. Most fields are at VE to V2 and look good, considering the temperatures and lack of sun. Soybean planting is about 90% complete, and soybeans are mostly not emerged to VE. A few fields in low areas had emerged soybeans that were killed by the frost on the night of May 9th. The top of alfalfa canopies were frosted in some areas roughly along and north of I-80 on the night of May 9th, but little damage was done. Frost injury to alfalfa and weed management dominated calls last week.”

Rainfall totals over the last week as of May 18th. Source:

Josh Michel (Region 11): “Most of the region has received anywhere from one up to three inches (in some isolated areas) of rainfall over the past seven days. Although fieldwork was paused for most of the week, the welcomed rain will help pastures and alfalfa fields. Planting progress estimates have slightly increased to 80-90% of the corn acres are planted and 60-65% of the soybean acres are planted. For crops planted the end of April, corn is mainly VE to V1 and soybeans VC to V1. Many corn seedlings that have emerged are looking slightly yellow. Warmer temperatures and some sunlight should help most of these quickly green up. Seedling emergence and stand assessments are still being conducted for frost injury. Recent field call questions have included CRP management, pasture management, stand assessments, replanting, new alfalfa seedings, weed identification and herbicide applications.”


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...