Heavy rainfall in areas, isolated hail, herbicide injury, weeds surviving post herbicide applications, and nutrient deficiencies were some of the common issues seen by ISU Extension field agronomists this last week. Read on for more specifics about what is happening across the state from your local ISU Extension and Outreach field agronomists.
Leah Ten Napel (Region 1):
Cherokee, Ida, Lyon, Monona, O'Brien, Osceola, Plymouth, Sioux, Woodbury counties
“The crops in NW Iowa are coming along nicely. Most corn fields have canopied. Soybean fields had been slow to progress but seem to be growing more rapidly in the last couple of weeks. Calls I have received this week have been on hail damage in isolated areas across the NW Iowa region and compaction issues becoming visible in corn fields by yellowing corn and uneven stands. Insect and disease reports have been low. Weed control issues are being reported from herbicide applications done in the past two weeks in soybean fields with the primary weed causing issues being waterhemp.
Josh Michel (Region 5):
Allamakee, Buchanan, Clayton, Delaware, Dubuque, Fayette, Jones, Linn, Winneshiek counties
“All of NE Iowa was able to receive some much-needed rainfall last week. Amounts were generally from 0.5 – 1.5 inches, with isolated heavier amounts of 2-2.5 inches along Hwy 20 between Waterloo and Dubuque. Despite the rainfall and high winds, many producers were able to continue post herbicide applications and side-dressing applications. Crops have finally started taking off and are growing quickly. Some of the early planted corn has reached V6-V7, while the later planted corn is around V3-V4. Early planted soybeans have reached V4, with some fields starting to bloom. Later planted soybeans are generally around V1-V2. Applicators are reminded to check herbicide labels if soybeans have started flowering. Approximately 80% of the oats are starting to head out, with 20% starting to turn. Alfalfa first cutting regrowth continues to do well. Some dairy operations have started second cutting. Pastures continue to look good despite warming temperatures. The majority of field calls this past week centered around weed identification and management, adjusting herbicide programs, and assessing various herbicide drift and crop injury reports.”
Meaghan Anderson (Region 7):
Boone, Dallas, Jasper, Madison, Marshall, Polk, Story, Tama, Warren counties
“Most of central Iowa received about 2-3 inches of rain in the last week. Parts of my western area were shorter on the rainfall and parts of my eastern area were much heavier, in some cases more than 5 inches of rain in 7 days. Central Iowa is generally much closer to normal rainfall for the last 30 and 60 days than other parts of the state who are either far above or below average. With more rainfall in the forecast, some crops will be struggling with waterlogged soils while other fields will benefit greatly from the rain during this period of rapid growth. Soybeans are just reaching first flower (R1) in some fields and corn is mostly V8-V13. Pest concerns have slowed down just ahead of the time for us to start finding clear signs of corn rootworm feeding on roots, Japanese beetles in soybean fields, etc. Some herbicide injury from earlier applications are persisting, probably due to the delayed rainfall after early May applications. Waterhemp survivors are prevalent in many crop fields and why weeds survived seems to be a common topic of conversation this week. Keep scouting!”
Rebecca Vittetoe (Region 8):
Iowa, Jefferson, Keokuk, Poweshiek, Washington, Johnson counties
“Rainfall totals across the counties I cover ranged from 0.2 to 3 inches between June 16 and June 22. Following the rain and wind on Friday, June 20, there were reports of leaning or downed corn fields in Keokuk County. Fortunately, most of the corn stood back up over the weekend. Corn mainly ranges from V8 to V14, and I expect to see some fields tasseling before the Fourth of July. This past week, my main concerns in corn were sulfur and potassium deficiencies, as well as waterhemp surviving post-emergence herbicide applications. Soybeans are beginning to reach the R1 (beginning flower) stage and have made significant progress over the past couple of weeks in size and color. Post-emergence herbicide applications are still ongoing in soybeans. If you're still spraying, be sure to double-check crop growth stages and herbicide label restrictions. Now is a good time to start assessing corn roots for rootworm feeding. Also, keep your eyes open for Japanese beetles.”
Virgil Schmitt (Region 9):
Cedar, Clinton, Des Moines, Henry, Jackson, Lee, Louisa, Muscatine, Scott counties
“Most of the area I cover received 0.5 to 2.5 inches of rain during the last week. Most corn is V9-V11 and generally looks good. Many fields have canopied over. Soybeans are mostly V4-V6 and also generally look good. I have not seen any blossoms yet, but I’m sure there are blossoms in some fields. Many post-emergence herbicide applications occurred last week. Oats are heading out and generally look good. Calls last week mostly centered around variable corn and soybean stand growth.”
Aaron Saeugling (Region 10):
Adair, Adams, Cass, Clarke, Decatur, East Pottawattamie, Fremont, Mills, Montgomery, Page, Ringgold, Taylor, Union, West Pottawattamie counties
“Soybeans are making up for the slow start this season with most soybeans in the V4 to V6 stage, and early soybeans are entering the R1 (beginning flower) stage and closing the canopy in narrow rows. Weed control is the primary field activity at this time with multiple combinations applied and crop response common under hot dry conditions. Corn is setting deep roots under the drier conditions here in SW Iowa, this should be helpful later in the year as we transition to hotter and drier July weather patterns. Corn in moisture limiting areas was rolling leaves over the weekend and is in need of moisture here this week. Corn plants in the V9 stage have all the ear shoots initiated, the plant also has approximately twenty leaves above ground and which can be visible after dissection, encased in the whorl. A new leaf emerges every 3 to 5 days depending, on GDDs being accumulated. Rescue herbicide and foliar applications need to be use with caution.”
Logan McCrea (Region 11):
Appanoose, Davis, Lucas, Mahaska, Marion, Monroe, Van Buren, Wapello, Wayne counties
“The past week consisted of some good precipitation across region 11, with most amounts coming in the 1-2 inch range. With those events came some higher winds, and some crop showed a bit of leaning, but I noticed a lot of it standing back up over the weekend with the heat pushing along the crop's growth. Corn continues to look good across much of the region, and some tassels will be starting to come out in the next 7-10 days on the early planted corn. Soybeans are starting to show some flowers and will be beginning their reproductive stages for the rest of the summer. They finally are starting to put some good color and size on them with many soybean fields being close to closing canopy. Lots of post emerge spraying was occurring in soybean fields last week as well. Some second cutting hay has begun, but with the forecast for this week looking wet, it will definitely be much slower going this week. Calls from the last week were mostly around herbicide injury and a little bit of wind injury concerns.”
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- Field Agronomist in EC/SE Iowa