Regional Crop Update: May 20 - June 4, 2024

June 4, 2024 3:00 PM
Blog Post

The last week brought some drier weather across the state for farmers to get back in the fields to plant as well as for other field activities to be completed including spraying, putting up first cutting hay, and sidedressing. Delayed planting, replant decisions, yellow corn, white grubs, true armyworms, weed pressure, and nitrogen loss concerns were some of the hot topics or issues Iowa State University Extension and Outreach field agronomists saw over the last week. Read on for more specifics.

Northwest Iowa

Leah Ten Napel (Region 1): “Because rainfall events were scattered all throughout planting season, we have crops in many different stages in my region of NW Iowa. Most early planted corn I see is in the V6 to V8 stages. Early planted soybeans I’ve seen are in the V2 to V3 stages. Recent warm weather has really progressed crops along. Strong winds and wet fields have made timely chemical application difficult as the crops continue to grow, and some growers are still unable to enter their fields. Make sure to consult chemical labels for crop stage and weed height before applying product for best efficacy and crop safety. I have seen some issues with emergence across my region. I strongly recommend growers get out and scout fields at this time to assess any issues. There may be planter issues that can be corrected before next year’s planting. Check out these two articles on corn and soybean stand assessments to refresh your memory before you head out to scout! In the last month my region has received 6-11 inches of rainfall. Because soil profiles were already near or at field capacity, this is causing some ponding issues. Growers should wait 3-5 days after water has receded to assess damage. If the corn growing point is soft and darkened, or the soybean’s growing points are showing no new growth, a decision should be made. Consider the economics of replanting when making your decision. Areas that are not replanted need good weed control throughout the growing season to avoid entire field weed control issues down the road.”

Gentry Sorenson (Region 2) “Continued rainfall has impacted planting progress for those trying to finish corn and soybean planting. Above average rainfall has occurred from April 10 through June 4. According to the Iowa Environmental Mesonet, 11.5 to 16.8 inches of precipitation has been recorded through this period in the counties I cover. Delayed plant workshops were held in Clay, Dickinson, and Palo Alto counties due to continued rainfall and saturated soil conditions that has made planting difficult. Corn growth stages range from VE to V4 and soybean growth stages range from VE to V2.  Waterhemp is present in many fields that I have visited the past several days. Scouting and post application treatments will be needed in those fields when they are able to be transacted after recent rains. Field work consists of planting, replanting, and post emergence spray operations. Phone calls and field calls have been about ponding issues, hail, prevent plant, questions on nitrogen losses due to saturated soils, and cover crop options.”

North Central Iowa

Angie Rieck-Hinz (Region 3): "Generally speaking, this past week is one of the drier weeks we had in NC Iowa in the past month, but with that said there are still localized areas where it has proven difficult to achieve any field work. Corn is VE to V6 and much like many areas, the corn is many different shades of green as it transitions into its nodal root system and starts to access available N.  Soybeans are VE to V3.  Today I started to notice iron deficiency chlorosis (IDC) in some of the early-planted fields. I have also seen minor bean leaf beetle feeding in soybeans. Our biggest challenges are 1) finishing planting; 2) weed control as there were a lot of fields planted “naked” and 3) being able to sidedress N in corn.  Most of my phone calls have been concerns about loss of nitrogen and weed control. There were many planters and sprayer running on Sunday, June 2 as folks try to knock out planting and spraying prior to the anticipated rain coming this week."

Corn leaf burn from sidedressed nitrogen.  Note the open slot from side-dressing into wet soils. Photo by Angie Rieck-Hinz. 

Northeast Iowa

Terry Basol (Region 4): “Operations were at a standstill the week of May 20 due to precipitation events occurring throughout the week. Last week was relatively dry, allowing farmers to get back into the field by midweek, and continue planting primarily soybean acres, but also finishing up on corn planting as well. Corn ranges from VE to V5 depending on planting date, and soybeans range from VE to V2.  According to the June 3 USDA NASS Crop Progress Report, 95 and 93% of the corn acres have been planted in NC and NE Iowa, respectively. For soybeans, 86 and 91% of the acres have been planted in in NC and NE Iowa, respectively. Harvest of first cutting hay is underway in the area. Oats have started to head out and look very good. Nitrogen sidedressing started at the end of last week, along with the first post emerge herbicide applications. Be sure to check labels and weed size limitations, as the time lag to get into fields due to recent rains have allowed the weeds to get ahead of us. Make sure to scout fields ahead of time so weed control choices/and or rates can be modified if needed. According to the Iowa Mesonet, the NE Iowa Research and Demonstration Farm at Nashua received 3.36 inches of rain the week of May 20 and 1.29 inches of rain the week of May 27, for a total of 4.65 inches in the last two weeks. Here’s hoping for drier weather to allow farmers to get required and needed field operations completed for the next week!”

Josh Michel (Region 5): “Over the past two weeks, most of NE Iowa generally received 5 to 6 inches of rainfall, with some isolated areas in Delaware and Dubuque Counties receiving up to 7 inches. Due to the persistent rainfall, the latest U.S. Drought Monitor now shows that all of the D1 (moderate drought) has been removed. Despite these heavy rain showers, farmers were able to take advantage of a few dry days to finish up planting and begin harvesting the first crop of alfalfa. Approximately 95% of the corn has been planted, along with 90% of the soybeans, respectively. Early planted corn fields can be staged up to V5, while recently planted corn fields are anywhere from VE to V2. True armyworms have been found feeding on young corn seedlings in isolated fields. Not surprisingly, there’s also been several cases of root rot from prolonged oversaturated soils. Soybeans follow a similar story, with earlier planted soybeans generally around V2, while recently planted soybeans are at VE to VC. There’s been noticeable insect feeding in some soybean fields from true armyworms and bean leaf beetles. I’ve also seen several fields with crusting issues and root rot concerns. Oats are starting to head out in many areas and so far, they continue to look really good. Many alfalfa fields are quickly reaching full bloom. Thankfully we had a couple short stretches of dry weather allowing about half of first crop to be put up. The pending forecast for this week, should allow for additional alfalfa to be harvested. Insect pressure in forages, specifically alfalfa weevils and potato leafhoppers, continues to be present. Recent field calls over the past two weeks have centered around forage management, weed identification and management, insect identification and management, along with a few calls about early corn and soybean growth and development.”

Bean leaf beetle
Bean leaf beetle found on a soybean plant causing some defoliation. Photo by Josh Michel. 

Central Iowa

Meaghan Anderson (Region 7): “We’ve had a bit of reprieve from the constant rainfall in the last week, which has finally allowed people to get closer to finishing up planting, replanting both corn and soybean, and POST spraying herbicides. Corn is speeding along, with much of the early-planted stuff at V6 or larger. I’ve noticed a lot of yellowing start to dissipate in the last few days, but you can still pick up the waves/stripes of anhydrous ammonia tracks in many fields. POST spraying in corn has gotten a good start, but I’ve noticed some fields with heavy weed pressure still, especially along field edges. There is a pocket in Madison and Warren counties where some fields have white grub pressure heavy enough to kill corn plants, so if you’re noticing small corn plants wilting and dying, check underground for the possible causes. Soybeans are as large as V3 and going through that phase where I begin to wonder if they’re ever going to take off and look really healthy. It shouldn’t be too much longer and we’ll likely see flowers. I’ve gotten a mixed bag of phone calls about insect issues, weeds, herbicide injury, hail damage, and nitrogen management this past week.”

White grubs found in a corn field in central Iowa. Photo by Meaghan Anderson. 


Corn plants that are actually dying due to white grub feeding in a central Iowa corn field. Photo by Meaghan Anderson. 

Southwest Iowa

Aaron Saeugling (Region 10): “What a difference a year makes! We have transitioned to” we can’t buy a rain to we can’t miss a rain”. It has been a challenging spring to get the crop planted. Most of the corn is planted in SW Iowa a few fields are still too wet, but much of the corn is in the ground the first time and a few fields for the second time. Corn that was able to withstand all the showers looks good and is in the V7 to V8 stage and growing fast. Spraying corn has been a challenge as well as some nitrogen loss in saturated portions of the field. Some corn is still in the “Ugly Duck” stage but hopefully will grow out of that with some heat and drier weather. Soybean planting is still happening in a few locations due to wet soil conditions. With a drier forecast later this week I anticipate many of the soybeans will be planted. Several fields have been replanted due to hail, rain, tornados, and flooding. Soybeans struggle with the wet soil and cool afternoons. Forage conditions for pastures are excellent, been several years since pastures were in this good of shape for early June. The other side is putting up hay has been more of a challenge with frequent rains. Some hay was baled last week, and I expect more hay to be mowed and baled this week.”

Flooding in a field in SW Iowa. Photo by Aaron Saeugling. 

East Central, Southeast, and South-Central Iowa

Rebecca Vittetoe (Region 8): “We had a relatively dry week (May 27-June 3) with rainfall totals ranging from 0.02 to 1.92 inches across my counties, with the heavier totals in my more northeastern counties. The week prior (May 20 – May 27), rainfall totals across my counties ranged from 1.6 to 6 plus inches.  With the drier conditions in the last week, there was a lot of field activity including from spraying, planting (replanting in some cases), putting up first cutting hay, and sidedressing nitrogen. Corn ranges from VE to V8, and soybeans range from VE to V2. There are a lot of yellow and uneven looking corn fields. Weed pressure, flooded areas, replanting decisions, hail damage, sidewall compaction, bean leaf beetles, nitrogen loss concerns, herbicide injury, and stink bug damage have been some of the issues or challenges I’ve seen in fields or have had questions on over the last week.”

Virgil Schmitt (Region 9): “Rainfall during the last two weeks in the counties I cover generally ranged from 1 inch to 3 inches with larger amounts to the north and lesser amounts to the south. High winds and hail did some damage to trees and buildings but little damage to crops, although a few emerged soybean fields were totally destroyed. Most farmers were able to find a few days to make good progress or wrap up planting, with the lesser rainfall amounts in the southern counties allowing those counties to make the most progress. Corn planting is about 95% complete. Most corn is about V4 to V6 and looks good. So far, I have not heard of any black cutworm problems. Soybean planting is about 90% complete. Most soybeans are at VC to V2. So far, I have not heard of any issues with bean leaf beetles. First cutting hay harvest is about 50% complete. Last week I received some contacts about true armyworm infestations in emerging soybeans in southwestern Muscatine County and in corn in southwester Cedar County. All those fields had a cereal rye cover crop. Identification, scouting, and management information can be found here. Contacts last two weeks mostly involved hay harvesting, corn rootworm hatch dates, European corn borer moth flight dates, true armyworms, soil fertility, and corn postemergence herbicides.”

Rainfall total map

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

ISU Extension Field Agronomist coverage map


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...