Regional Crop Update: April 8 - April 23, 2024

Recent rains, cooler temperatures, and the windier conditions have slowed field activities. According to the May 22 NASS Crop Progress Report, 13% of the corn acres and 9% of the soybean acres have been planted. Some of the first planted corn and soybeans have emerged or are getting close to emerging. Planting considerations, alfalfa weevil, seeding forages, winter annual weeds, and cover crop termination have been some of hot topics ISU Extension and Outreach Field Agronomists have been seeing or getting questions on. Read on for more for more specifics on what’s happening in different areas across the state.  

Northwest Iowa

Leah Ten Napel (Region 1): “Spring is in full swing in the NW corner of the state. Planters and sprayers are running through the fields. Final fertilizer applications are being made. Soil temperatures are inching close to 50 degrees and rising, and the soil moisture levels are making for great seedbed conditions. The southern half of my territory is still seeing dry conditions, while the northern half has caught significant rains in the last month. Some of those rains have led to erosion issues in early worked fields, and high winds have made timely liquid nitrogen and chemical applications more difficult.”

Gentry Sorenson (Region 2): “Rainfall consisted of around 1.5 to 2 inches across my region from April 15 through April 23. The rainfall provided a break in planting due to wet conditions in the field, and the wind has been prevalent for the past several days making herbicide applications difficult. Prior to the rainfall, applications of nitrogen, dry fertilizer, and tillage work were prevalent. Some planting was completed before the rain. Crop planting progress as of April 21 was 19% for corn in NW Iowa, although progress varied greatly by neighborhood. Growing Degree Day (GDD) accumulation is around 90 to 100 GDDs from April 10 to April 23 for my region. Farmers were able to get back into the field on Monday, April 22 and Tuesday, April 23, with planting prevalent. Phone calls consisted of questions on nitrogen, phosphorous, and potassium and general planting questions."

North Central Iowa

Angie Rieck-Hinz (Region 3): “Planting has started in NC Iowa with some early planted acres and a lot more acres planted April 13-15. Rain and cooler temperatures put a damper on field activities for most of NC Iowa for the remainder of the week of April 15. Rainfall amounts varied across the area last week, with 1.29 inches at Webster City and 2.14 inches at Hampton. I spotted one field of emerged corn along Highway 20 on Saturday. I have been catching black cutworm moths and true armyworm moths in my traps, which are located north of Jewell. The latest moth trapping report is posted weekly on the ICM Blog. I have yet to find any alfalfa weevils in NC Iowa, but my colleagues in southern Iowa have been finding a lot of alfalfa weevils. I have been finding a lot of pea aphids in alfalfa.”

Northeast Iowa

Josh Michel (Region 5): “Over the past two weeks, most of Northeast Iowa has received anywhere from 1.50 to over 3 inches of rainfall. This has done a great job of helping to alleviate some of the prolonged moisture stress as indicated by the latest drought monitor. Four-inch soil temperatures over the past week have continued to hover in the mid to upper 40’s, but warmer weather forecasted for this week has encouraged many farmers to continue field operations with near-perfect field conditions across most of the area. Many pastures and alfalfa fields are quickly greening up in response to the recent rain and warming temperatures. As a result, farmers should start scouting for alfalfa weevils. I’ve seen several fields with early alfalfa weevil instars starting to become active. Other recent field calls have centered around cover crop termination, pasture weed ID and management, and soil temperatures and planting conditions.”

Central Iowa

Meaghan Anderson (Region 7): “Central Iowa received mostly between 1 to 2 inches of much-needed rainfall in the last week or so, with a few isolated areas receiving more or less rainfall. Between the rainfall and the cooler low temperatures over the weekend, most people won’t get back in the field until early this week. Lots of planting happened during the warm spell, with a mixture of corn and soybean going in the ground. I’ve seen a lot of terminated cover crop fields and herbicides applied, though the wind has made it challenging. Phone calls have been the usual spring ones – fertilizer apps, seeding pastures/hay, “oops” calls about planting too many seeds or spraying the wrong herbicide, etc. In my field scouting, I’ve seen lots of the normal early weeds already up and even found emerged woolly cupgrass on April 17.”

East Central, Southeast, and South-Central Iowa

Rebecca Vittetoe (Region 8): “Prior to last week there was a flurry of field activities happening across the east-central part of the state ranging from fertilizer and herbicide applications to corn and soybean planting. Rainfall totals over the last two weeks ranged from just shy of 1 inch to over 2 inches in areas. Field activity has been slowly picking back up here in the last day or so. While fields may look dry on top, they are not fit underneath. Alfalfa weevil larvae, pea aphids, and lygus bugs are present and active in alfalfa fields. Take time to scout your fields. Also be on the lookout for bean leaf beetles once those first planted soybean fields emerge. Questions the last couple of weeks have been on fertilizer applications, seeding forages, alfalfa weevils, herbicide applications, terminating cover crops, and planting considerations.”   

Virgil Schmitt (Region 9): “Rainfall during the last two weeks in the counties I cover generally ranged from 1.5 to 3.0 inches. Some areas where tillage had occurred on sloping land saw extensive erosion with the rainfall event on April 16. Although some corn (about 10 – 15%) and soybeans (about 10%) have been planted, in general farmers are waiting for consistently warmer soil temperatures and drier soils. Past and projected soil temperatures may be monitored here. There is considerable discussion and speculation regarding crops that have already been planted. Mark Licht, ISU Extension Cropping Systems Specialist does not expect major problems due to the timing of the cold weather compared to when planting was shut down by rainfall. The winter annual weeds henbit, purple deadnettle, shepherd’s purse, pennycress, and yellow rocket are blooming. Common chickweed, another winter annual, is plentiful in some fields. Read more on winter annuals and other early-season weeds here. Bluegrass is heading out. Alfalfa weevils are reaching impressive numbers in some alfalfa fields, so alfalfa fields should be scouted closely, and management should occur if thresholds are exceeded. Phone calls, emails, and field visits last two weeks mostly involved forage stand evaluations and recommendations, alfalfa weevils, soil erosion, and identification and management of winter annuals and biennials.” 

Clarabell Probasco (Region 11): “The south-central portion of the state has seen a little progress on this year’s planting season. Some growers were able to get in a field or two to plant before the recent round of rain showers began. These rain showers brought a total of 1 to 2 inches for most of the region. Field activities have continued to take place with pre-herbicide applications, tillage, anhydrous, and dry fertilizer all being seen. Field calls have been largely directed towards alfalfa fields where heavy pressure is starting to be seen in some areas from alfalfa weevil larvae feeding. Look through this article to double check on the methods used to determine if alfalfa weevil pressure warrants action for control or not.”

Check out the map below to find your local ISU Extension field agronomist and find their contact information here!