While some areas across the state were grateful for recent rainfall, others received excessive amounts, resulting in standing water in fields and raising concerns about nitrogen needs for corn. Along with the wetter conditions, ISU Extension field agronomists reported observations and inquiries about wind and hail damage from localized storms, the presence of Japanese beetles, corn rootworm injury, herbicide drift issues, weeds surviving herbicide applications, and what’s being seen for disease pressure so far. Read on for more insights into what’s being seen in fields across the state.
Leah Ten Napel (Region 1):
Cherokee, Ida, Lyon, Monona, O'Brien, Osceola, Plymouth, Sioux, Woodbury counties
“Corn and soybean fields are at or very near reproductive stages in the NW region of the state. As flowers and tassels begin to pop up, we need to be on the lookout for pest that can cause excess stress to our crops. Rainfall in this corner of the state has been helpful for crop development, but areas where it has caused delays in herbicide application may be dealing with weed control issues. Some storm damage is also accompanying the rainfall, leaving fields with hail or wind damage. Disease and insect reports have been low, but scouting throughout the upcoming weeks will be critical to catch pest issues before they become widespread in crop fields.”
Angie Rieck-Hinz (Region 3):
Cerro Gordo, Franklin, Hamilton, Hardin, Humboldt, Webster, Worth, Wright counties
“It was a wet week from June 23 through June 30, with rainstorms that continuously rained over parts of north central Iowa. Mason City has received 10.16 inches of rain from June 1 through June 30, which is 4.90 inches above average. An even broader perspective says it has just plain been wet. See the map below depicting rainfall from April 1 through June 29 from the ISU Mesonet. The two primary concerns are 1) finishing up post-application herbicide spraying in soybeans and, 2) the corn crop is turning yellow due to saturated soils and loss of N. Other phone call included concerns about Japanese beetles, and herbicide drift complaints. On another note, thank you to all who attended the Open House to celebrate the new research and extension facility at the Northern Research Farm last week! Despite 4.4 inches of rain leading up to and during the event, a tornado warning, and a huge pivot when we could not take folks on the research plot tour, everyone enjoyed the celebration recognizing our donors and members.
Terry Basol (Region 4):
Benton, Black Hawk, Bremer, Butler, Chickasaw, Floyd, Grundy, Howard, Mitchell counties
“Crops in my region are continuing to look pretty good. Corn ranges from V8 – V10 for most of the acres. Soybeans have begun their reproductive stages and range from R1– R2. Field operations have been slow due to the precipitation events that have occurred in the area for the past couple of weeks. Some producers are working on getting the last of the nitrogen sidedressing applications completed before the corn gets too tall to get the toolbar/applicator across the field without damaging the corn. For soybeans, first applications of post-emerge herbicides have been conducted in the area and efficacy assessments have been taking place, with some acres looking to receive a second application. Make sure and consult the herbicide labels, as some have restrictions once the soybeans reach the reproductive stages. Begin scouting corn for corn rootworm feeding by conducting root digs and the “float test”, particularly in fields that have been continuous corn for more than 3-4 years and those that have a history of trait failure. Second cutting of hay has begun, with 8 and 21% completed in NC and NE Iowa, respectively according to the June 29 USDA-NASS Crop Progress Report. We have received ample amounts of rain over the past couple of weeks at the Northeast Iowa Research and Demonstration Farm near Nashua. Two weeks ago (June 16 – June 22) we received a total of 3.52 inches of rain, and last week we received 2.18 inches according to the Iowa Mesonet. Looking at the month of June, the farm received 8.52 inches of rain and for the growing season so far (April 1 through June 30) 15.8 inches of rain.”
Meaghan Anderson (Region 7):
Boone, Dallas, Jasper, Madison, Marshall, Polk, Story, Tama, Warren counties
“Central Iowa had another week of significant rainfall ranging from about 1.5 to 6+ inches. Unfortunately, this rain was too much for some fields and resulted in standing water in some fields and significant runoff in other areas. The combination of moisture and heat has the crop growth on overdrive, with soybeans at R1/R2 and corn reaching late vegetative stages. A few tassels are out on the landscape, but I haven’t seen a field at VT yet. Field calls have lulled a bit, aside from concerns about nitrogen needs for corn and weeds surviving postemergence herbicide applications. Questions have begun to come in regarding corn rootworm feeding, tar spot, and white mold. Keep an eye on our events page for upcoming opportunities!”
Rebecca Vittetoe (Region 8):
Iowa, Jefferson, Keokuk, Poweshiek, Washington, Johnson counties
“Over the past week, 1 to 3 inches of rain fell across the counties I cover. With showers on and off throughout the week, field activities were somewhat limited. Corn is in the late vegetative stages. While I haven’t yet seen an entire field at VT, tassels are starting to peek out in some areas. Soybeans are mostly in the R1 to R2 stages. Over the weekend and into Monday, I observed several hayfields being mowed for the second cutting. Most field calls and questions have focused on weed control concerns, corn rootworm feeding, Japanese beetles, herbicide drift injury, foliar diseases in corn (tar spot and gray leaf spot), and the potential for white mold or frogeye leaf spot in soybeans. Despite the concerns and questions, I’ve received about diseases, I have yet to see any in the fields I’ve visited. Continue to keep scouting your fields though.”
Virgil Schmitt (Region 9):
Cedar, Clinton, Des Moines, Henry, Jackson, Lee, Louisa, Muscatine, Scott counties
“Most of the area I cover received 0.25 to 1.5 inches of rain during the last week. Most corn is V11 to V13 and generally looks good. I have not seen any commercial corn fields tasseled yet. Soybeans are mostly R1 to R2 and generally look good. Oats continue being headed out and generally look good. I have not seen any turning color yet. We are in lapping time with hay harvest as a few fields of first cutting hay were mowed last week and the first mowing of second cutting was also occurring in some fields. Potato leafhopper injury is evident in some fields. Calls last week mostly centered around variable corn height, thickening up soybean stands, nitrogen side-dressing rates, soil test interpretations, and weed management.”
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- Field Agronomist in EC/SE Iowa