Regional Crop Update: May 4 - May 12, 2020

May 12, 2020 8:53 PM
Blog Post

What a difference the year makes! According to the May 11th USDA Crop Progress Report, 91% of the expected corn crop and 71% of the expected soybean crop has been planted, which is nearly a month ahead of last year’s planting pace and two weeks ahead of the five-year average. The big news for this last week was the colder temperatures over the weekend and frost injury concerns to emerged crops and forages. Check out what ISU Extension field agronomists are seeing and hearing around the state for field conditions and planting progress.   

Northwest Iowa

Joel DeJong (Region 1): “We had several nights with lows around 30 degrees F in NW Iowa but not much below that. Crop injury was limited, it appears, although you can find an occasional corn plant that had tissue killed by frost. The growing point looks good on the plants I cut open, so I suspect most will resume growth once it warms up again. Not many soybeans are emerged, and those I found look as if they survived the frost OK in the area. While looking, it was easy to find some emerged grasses along field edges, mostly woolly cupgrass. Scouting for weeds escaping pre herbicides might be more important this year. Soybean planting slowly progressed even with the cold temperatures over this last week. We are likely approaching the 80% range of soybeans planted, with almost all the corn in the ground. It’s been a long time since a good rain shower – so one good rain, in conjunction with warmer weather, and a resumption of plant-able days will get us wrapped up soon. Alfalfa measurements for using the PEAQ method to determine when to take the first cutting of alfalfa yesterday (May 11th) were from 14 to 17 inches in height. That growth, too, will resume rapidly with the forecast for much warmer temperatures early next week. I found no alfalfa weevil issues yet.” 

Paul Kassel (Region 2): “This week has been quiet. Corn planting and soybean planting is mostly complete; however, there are still a few soybean acres to be planted. Pre-emergence herbicide applications on soybeans is also nearly complete. While there was a lot of concern on frost injury to both the corn and soybean crops, at this time it appears that the injury is limited. There were relatively few soybean fields with emerged plants. Nevertheless, farmers and agronomists are advised to check and assess corn and soybean fields. The next big field work activity will be post emergence herbicide applications to corn; however, currently there is not much urgency because of the slow development of both the corn and the weeds.”

Corn plants retain a yellowish color after several mornings of temperatures in the low 30’s F. Photo courtesy of Paul Kassel.

North Central Iowa

Angie Rieck-Hinz (Region 3): “Planting progress continued last week, and the May 11th USDA Crop Report showed NC Iowa at 97% of the corn planted and 85% of the soybeans planted with 5.3 days suitable for fieldwork. Conditions remained ideal for planting and in most places the top inch to two inches of soil is relatively dry. Cold temperatures on the morning of Saturday, May 9th hovered around 28 degrees F at my house, 25 degrees F in Webster City and 26 degrees F at Hampton. Late Saturday afternoon when the front pushed through Iowa, we experienced some horrible amounts of blowing soil that prove water erosion is not the only kind of erosion we have here in Iowa, as illustrated in the photo below. I have received very few calls about freeze or frost damaged crops, but I took the following pictures showing the varying degrees of freeze-injury to corn on May 11th near Kamrar. Other phone calls of concern this week included slow growth on pastures, management factors for pasture, and post-applied nitrogen for corn.”

Dust storm captured on Saturday, May 9 at 6 p.m. in northern Story County. Photo courtesy of Angie Rieck-Hinz.

Varying degrees of freeze injury on corn seedings in Hamilton County (photo taken May 11th at 7:30 a.m). Photo courtesy of Angie Rieck-Hinz. 

More severe frost/freeze injury on corn in a low-lying area of a field; however, notice the regrowth at the base of the dead leaf tissue (photo taken May 11th near Kamrar). Photo courtesy of Angie Rieck-Hinz. 

Northeast Iowa

Terry Basol (Region 4): “This past week has provided good planting conditions to help growers in my area either finish with both corn and soybean planting or get very close to finishing. According to the May 11th USDA Crop Progress Report, farmers in NC and NE Iowa have 97% and 88% of the corn acres planted. On the soybean side, the May 11th Crop Progress Report had 85% and 76% of the soybeans planted in NC and NE Iowa, respectively. Both corn and some soybeans have begun to emerge from the early planting dates. We did get a little dust settling from a weather system that came through last Tuesday, May  5th, giving us an average of a half-inch of rain. Record lows were recorded for this area on Saturday, May 9th with Waterloo getting down to 25 degrees F and the ISU NE Iowa Research and Demonstration Farm getting down to 23 degrees F. Corn should be fine, as the growing point is still below the soil surface. Most emerged soybeans would be at VE (cotyledons pulled through the soil surface), and although the growing point is above ground the cotyledons are resilient to cold temperatures. Nevertheless, it will be important to scout and assess the corn and soybean fields that had emerged at the time of these low temperatures approximately three to five days after Saturday’s cold temperatures to able to assess living versus damaged or injured tissues or plants.”

Minimu low temperatures across the state of Iowa from May 8th through May 12th. Source: Iowa Environmental Mesonet.

Central Iowa

Meaghan Anderson (Region 7): “The big news of the last week was the cold temperatures that came through the state this past weekend. Low temperatures got below freezing for a short time across part of central Iowa, and with our early wrap up to planting this year, many crops were already emerging. Later this week will be an excellent time to scout and observe recovery of plants that may have suffered frost damage. While we’ve gotten some rainfall (and expect more this week!) and our PRE herbicides are hopefully working effectively now, keep an eye out while scouting emerged crops for weeds that may have snuck through the PRE during the dry period in April. I’ve noticed velvetleaf and grasses (likely giant foxtail) surviving well in crop fields. Questions in the last week have been primarily about managing cover crops, herbicide restrictions to planting, and what will happen with the cold temperatures and our crops.”

Velvetleaf seedlings emerging in a crop field in central Iowa (photo taken May 7th). Photo courtesy of Meaghan Anderson.

Southwest and West Central

Mike Witt (Region 6): “Corn and soybeans are emerging across WC Iowa. Corn planting is over 90% complete and soybeans over 70% for the area.  With the early planting and colder temperature many are reporting yellow-looking corn. These plants just need a little warmth and sunlight to perk up. There were patchy areas of frost this last weekend. I have had few reports of widespread frost damage in WC Iowa. All crops should recover if they were damaged, but it is important to scout your fields and do stand assessments. Also check weed pressures in these areas as herbicides do their best work on growing weeds and frosted or slow growth will mean slower herbicides interactions. While scouting, some early season pests to be on the lookout for include true armyworm, black cutworm, bean leaf beetles and alfalfa weevils. Pained lady butterflies (adult thistle caterpillars) have been found in Iowa. The rain in the forecast for the end of this week in WC Iowa should give farmers a small break to get ready for the next round of field activities.”

Emerged corn in WC Iowa that needs a blanket and a warm cup of coffee. Photo courtesy of Mike Witt.

Aaron Saeugling (Region 10): “Cool temperatures and scattered light rain showers occurred over the last week. However, portions of Pottawattamie and Cass counties are abnormally dry. With the limited rainfall, pastures and newly seeded alfalfa need a soaking rainfall. Pasture growth and winter small grain growth is slow this spring. Most all the corn is planted, and I would guess 80% of the soybeans have been planted. Cool conditions nipped emerged corn and soybean plants over the weekend.  Additionally, most of the spraying is caught up due to a dry spring. Expect some pre-emerge weed escapes on herbicide applications due to lack of soaking rains and slow crop growth.” 

East Central, Southeast, and South Central:

Rebecca Vittetoe (Region 8): “While the rainfall the past week was welcomed, the colder temperatures and frost over the weekend were not welcomed. Corn planting is winding down and two-thirds to three-quarters of the soybeans have been planted across my region. Many farmers have finished planting altogether. For the crops that have emerged, corn is mainly VE to V1 and soybeans are mainly VE. The cold temperatures did cause frost injury to emerged crops and forages, however it is important to be patient and wait three to five days after the frost to really evaluate how plants are recovering. So far the corn and alfalfa seedlings I've looked at appear to be coming out of it just fine. For those with alfalfa, do scout for alfalfa weevils as I was able to find a few adults and larvae in an alfalfa field in Washington County I was in to take a PEAQ measurement, which the alfalfa averaged between 16 to 17 inches in height. Common questions this past week have been on weed identification, herbicide considerations (mainly on dry conditions earlier and PRE’s or spraying after the frost), replanting considerations, black cutworm predicted cutting dates, and cold weather/frost concerns.”

Scout alfalfa fields for aflalfa weevils; adults and larvae have been observed in an alfalfa field in Washington County (photo take on May 12th). Photo courtesy of Rebecca Vittetoe.

Soybeans planted on May 21st at the SE Research Farm showing frost injury. Photo courtesy of Cody Schneider.

Virgil Schmitt (Region 9): “Rainfall in the last week has generally been light with under one inch of precipitation reported nearly everywhere in the counties I cover. The weather allowed for a great deal of planting and spraying to occur. I estimate that about 90% of the corn is planted and about two-thirds of the soybeans are now planted. It appears that with the cold temperatures over the weekend that there was some frost damage to emerged crops. Herbicides, herbicide drift, and soybean populations dominated calls last week.”

Rainfall totals over the last week. Source:

Josh Michel (Region 11): “Some welcomed rain slowed down fieldwork for a couple days across most of my region last week. Most areas received anywhere from 0.25 to 0.5 inch of rainfall. Although the rain will help alfalfa fields and pastures continue to grow, much of the region could use some additional moisture. Many farmers have either completed planting for the year, or they hope to finish up within the next couple days. Corn and soybeans planted at the end of April are at VE to V1 and VC to V1, respectively. There are some concerns about recent cold temperatures and possible frost injury to crops and forages. Some areas did experience freezing temperatures for up to three hours. Farmers should wait to scout these areas till later this week to know what the impact was for sure on their crops. Recent field calls have included alfalfa weevils, forage management, 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...