Recent rainfall brought some much-needed moisture to many parts of Iowa, but totals varied widely. Unfortunately, some of the recent rainfall events also resulted in localized flooding and some storm damage. Common challenges or issues reported by ISU Extension and Outreach field agronomists across the state include weed pressure, herbicide injury, black cutworms, white grubs, and thistle caterpillars. Read on for more specific updates on what’s happening in fields across the state.
Leah Ten Napel (Region 1)
Cherokee, Ida, Lyon, Monona, O'Brien, Osceola, Plymouth, Sioux, Woodbury counties
“Crops in northwest Iowa are progressing nicely. Early planted corn is in the V8–V9 stages, while soybeans range from V2–V4. Precipitation has been variable across the region. Areas with little rainfall saw corn leaves rolling last week. The main insect pest being reported is white grubs. The ICM news article “True White Grub Identification and Management” has more on this pest. There has been little disease pressure so far, but weed pressure is increasing. Many corn acres were sprayed last week, and soybean post applications will follow soon. Forage and pasture fields are growing strong.”
Angie Rieck-Hinz (Region 3)
Cerro Gordo, Franklin, Hamilton, Hardin, Humboldt, Webster, Worth, Wright counties
“Corn is V4 –V7, and soybeans are V2–V4 across north-central Iowa. Generally speaking, crops are looking good. However, as I usually travel from where I live in Story County to the north, you can see it is much drier the further north you go. Last week while assessing the oat variety trial at the Northern Research Farm, you could see how much the oats were responding to the heat and dry winds over the course of the two hours we were out there. I have received numerous calls from farmers expressing concern over the dry conditions. For the most part corn postemergence herbicide applications are complete, and soybean postemergence applications are starting. Nearly all calls this last week were about herbicide issues, from wrong product put on the wrong crop and tank contamination to numerous drift complaints to neighboring row crop fields, pastures, gardens and lawns. The drift issues are often downright blatant, where comments like “who cares, it’s just a pasture”, are often heard.”
Josh Michel (Region 5)
Allamakee, Buchanan, Clayton, Delaware, Dubuque, Fayette, Jones, Linn, Winneshiek counties
“Dry conditions early last week allowed field operations and postemergence herbicide applications to get finished up across most of the region. Several rounds of thunderstorms came through the area late in the week and rainfall totals ranged from 1.5 to 2.5 inches, with some isolated heavier amounts of up to 4.5 inches. Another round of storms came through the area on Sunday evening and early Monday morning, with totals ranging from 0.5 to 1 inch. In general, most of the corn is around V2–V4, while soybeans are at V1–V2. Oats continue to look good to excellent, with a few early-planted fields beginning to head out. Alfalfa regrowth is coming back nicely after first cutting, with minimum insect pressure. Pastures also continue to look good, with many cool-season grasses headed out. The majority of field calls over the past week have centered around weed identification and management, as well as herbicide drift and injury.”
Meaghan Anderson (Region 7)
Boone, Dallas, Jasper, Madison, Marshall, Polk, Story, Tama, Warren counties
“Central Iowa received sufficient to excess rainfall in the last week, with some areas receiving over four inches in the late week/weekend rainstorms. With more rain predicted this week, applicators are doing their best to treat weeds when conditions are good. Corn varies from about V4 to V8 and soybeans vary from recently emerged to V4, very nearly R1. Herbicide applications have mostly finished in corn and applicators are moving on to soybean, nitrogen sidedressing is ongoing, and hay has been mostly put up. I've received a few reports of pest issues, including Anthracnose in corn, white grubs feeding on corn roots, and a few other one-off insect issues in soybean and corn. Weeds continue to grow rapidly, with some fields full of shocking amounts of giant ragweed, waterhemp, and Asian copperleaf; I'll be monitoring some fields in the 7-10 days after the postemergence applications to be sure they were effectively controlled. Calls in the last week mainly centered around herbicide drift concerns, pasture management, weed identification, and fungicide applications.”
Rebecca Vittetoe (Region 8)
Iowa, Jefferson, Keokuk, Poweshiek, Washington, Johnson counties
“Prior to the rain over the weekend and early this week, dry conditions were becoming evident in some fields, particularly fields with any rooting or compaction issues. Rainfall totals ranged from about 1 to 3 inches; with isolated higher amounts. Corn ranges from V4–V9, and the earlier planted fields are nearing canopy closure. Soybeans are V2– V4. Field activities included postemergence herbicide applications in corn, sidedressing, and finishing putting up the first cutting of hay. Reports of black cutworm feeding continued last week, along with my first report of thistle caterpillars. I haven’t seen them yet myself, but based on Growing Degree Days, Japanese beetles should be emerging. The first cutting of hay has been put up, and the recent rain should help with regrowth. Questions this past week included weed identification, weed management questions, herbicide injury (tank contamination and drift), and cutworm activity.”
Virgil Schmitt (Region 9)
Cedar, Clinton, Des Moines, Henry, Jackson, Lee, Louisa, Muscatine, Scott counties
“During the last week, the counties I cover have generally received less than 0.5 inch of rain roughly south of Interstate 80 and up to 3.0 inches near Highway 20. Isolated areas did see higher totals exceeding 5 inches of rain. Most corn fields are V5–V7 and look good. Postemergence herbicide applications pretty-well wrapped up last week. Most soybeans are mostly V2–V3 and look good. Some farmers have fields in dire need of a postemergence herbicide application and some of those farmers are waiting nervously for their commercial applicator to make the switch from corn herbicides to soybean herbicides. Oats continue to look good, and forages are doing well. Calls last week centered around weeds, weed management, spray tank contamination, and forage insects.”
Aaron Saeugling (Region 10)
Adair, Adams, Cass, Clarke, Decatur, East Pottawattamie, Fremont, Mills, Montgomery, Page, Ringgold, Taylor, Union, West Pottawattamie counties
“Summer has arrived. Crop conditions are variable across the region. The western and northern part of southwest Iowa is not as wet as the Highway 34 and Highway 2 corridors. Those areas have received several storms and large rainfall events causing some flooding. Corn is hitting full stride now and is in the V5–V9 stage, depending on planting date. Most corn postemergence herbicides have sprayed. Soybeans are the focus for the next two weeks for herbicide applications. Farmers need to be scouting for insect pressure in the coming weeks as well as checking weed emergence, identification, and size to be successful with postemergence herbicide applications. I did find me first thistle caterpillar adult, so that is concerning this early in the season. First cutting of grass and alfalfa forage has harvested and the quality looks to be good. Pastures are in good condition with the rainfall and ponds filled back up. Pasture weeds are getting large, especially poison hemlock, hemp, wild parsnip, and thistles. Now is the time to start spot spraying, mowing, and cutting weeds in pastures. Cool-season grasses are all headed out and pollen shed is occurring –be looking for pink eye in cattle.”
Logan McCrea (Region 11)
Appanoose, Davis, Lucas, Mahaska, Marion, Monroe, Van Buren, Wapello, Wayne counties
“The end of last week was rather soggy for south-central Iowa, with parts of Marion, Lucas, and Monroe counties getting upwards of 5 inches of rain in some spots, along with severe storms that brought some hail and wind. Eastern portions of my territory received precipitation as well, but more in the 1 to 2 inch range. Mother nature does not appear to be letting up this week either, with more chances of rain and severe weather on the way. Corn ranges from V3–V9, depending upon planting date. I noticed over the weekend some yellow leaves starting to stick out in the canopy of some corn fields, meaning that rapid growth syndrome has arrived with the precipitation and warm weather. Soybeans range from V1–V4 and have been growing slowly recently. Weeds are accumulating plenty of size and will become difficult to control if weather continues to keep folks out of the field. Though there were plenty of sprayers in the fields last week prior to the rain. Most of first cutting hay has been put up, though there are some straggler fields that will be waiting quite a while now with the way that the weather looks. Pastures of course love the rainfall and look very good. Calls over the past week have mainly been surrounding herbicides, with injury and drift being the main topics.”
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- Field Agronomist in EC/SE Iowa