Iowa crop update for June 13 to June 19, 2016

June 20, 2016 5:11 PM
Blog Post

Iowa Crop Progress Summary
The USDA Weekly Crop Progress Report stated Iowa's corn crop has a good/excellent rating of 79%, above the current national average of 75%. The agency reported all of Iowa's soybeans as planted and 97% emerged, ahead of the 5-year-average by 9%. Iowa soybeans were given a good/excellent rating of 80%, and 17% are considered in fair condition. The U.S. Drought Monitor classifies southeast Iowa as abnormally dry on its intensity scale.

Iowa State University Extension and Outreach field agronomists report crop conditions in your area of the state:

Joel DeJong:
On Friday evening of last week (June 17), a storm system rolled through the northwest corner of Iowa. A 1-3 mile wide strip of hail damage from the NW edge of Plymouth County to near the SE corner of the county, and proceeding a few miles into Woodbury County, really did some significant damage to many crop fields. As with any hailstorm, there was a range of injury to crops in the path of this storm. Some were totally demolished, some could recover quite well. Many producers in the heart of the storm are replanting soybeans. Cornfields fared relatively better than soybean fields, but some of them are nearly totally gone, too. These will create tougher decisions. Read more.

Paul Kassel: Corn planted May 17 is around the V9 stage, corn planted May 7 is at V7, and May 16 corn is at V6. The crop looks good. My region had some decent rainfall last week, with Dickinson County receiving excess rain. Soybeans planted in April are at V4, and June-planted soybeans are around V1.

There have been some alleged group 9 and 27 herbicide resistance (3.6 pt/a Halex Gt) claims in the area, but it might just be poor control. Soybean preemergence herbicides are working well, but waterhemp is coming to life. There will be lots of herbicide application to soybeans this week.

North Central
Angie Rieck-Hinz: Corn in north central Iowa is V8-V11 with some quickly approaching V12. There have been some scattered reports of northern corn leaf blight, but at very low levels. Rooting issues are becoming increasingly noticeable in fields where planting depth was not ideal or from compaction. Postemergence herbicide applications in corn are mostly done. I did see two corn fields being cultivated last week! Some fields are showing what I anticipate is probably sulfur deficiency symptoms- especially on our eroded side slopes. Soybeans are V2-V5, and I have seen a couple of fields that are just beginning to flower. Postemergence herbicide applications continue. I did find potato leafhoppers in cut alfalfa fields last week--not at threshold, but warrants scouting. 

Rainfall across my counties has been more than abundant in that Fort Dodge to Lehigh area; same for parts of Cerro Gordo and Worth counties. However, parts of southern Hamilton and southern Hardin counties have corn exhibiting rolled leaves for nearly 10 days now. Rainfall for the Eldora area shows we are 4.38 inches behind the norm for April 1 through June 19. 

Terry Basol: This past week, we received some rain across the area, particularly Tuesday (June 14) afternoon and evening. According to the Mesonet, the ISU Northeast Research and Demonstration Farm near Nashua, Iowa received 1.7 inches of rain from that system. There were isolated cases of more rainfall across the territory, which included up to 7 inches of rain east of Osage with flash flooding.

Most of the corn is at V6-V9 growth stage with a lot of it giving canopy closure over the row. Besides the areas that received too much rain, the corn is looking good with a dark green color and nodal roots taking over. Most of the soybeans are at the V2-V4 growth stage. The weather last week gave most growers in the area a chance to get their first round of postemergence applications completed on the soybeans late in the week. First cutting hay has essentially all been harvested with a good growth of the second cutting well underway.

Brian Lang: Once the first crop of alfalfa is harvested, it’s time scout for potato leafhopper (PLH). Consider your first scout 7-10 days after cutting the first crop. A simple threshold rule that still basically holds true is one or more PLH per inch height of alfalfa per 10 sweeps. In other words, if I take 10 sweeps on 4-inch tall alfalfa, I reached threshold if I find four or more PLH in the net. Owning a sweep net is an excellent investment. Thresholds are based on a 15-inch diameter net, and taking about a 3-4 foot sweep across the alfalfa canopy with the edge of the net about halfway into the canopy.  If PLH are present, they are easy to kill. The lowest labeled rates work very well on this pest. Also scout the new seedlings, including those with oat nurse crops. The same pest thresholds apply.

West Central and Southwest
Michael Witt: Corn is around the V6-V9 stages on average for the area. The crops are generally healthy with some water stress showing in afternoons due to hot temperatures and lack of moisture. Corn roots are developing deep into the soil profile in their search for water which will help with later season stability. There are also reports of rapid growth syndrome (RGS) in corn, causing flag leaf flashing and some general rolling or twisting of whorls in certain hybrids. Soybeans are ranging in maturity from V3- V6 with a high variability of stages due to planting times. Japanese beetles are starting to appear as well as other summer insects, so scouting time for insects is upon us.

Aerial applications are also beginning across the region for fungicide and insecticides, so keep an eye to the sky. Subsoil moisture across the region is dropping, but not to significant levels to register on the drought monitors yet. Herbicide spray is continuing across the area for corn and soybeans with only general problems reported. There are chances of needed rain this week, but they are spotty and not widespread at this point. Temperatures will range from the upper 80’s to lower 90’s during the day and drop to upper 60’s and lower 70’s at night. The continued monitoring of weed pressures for escapes, insect damage, and general crop health so that things don’t “sneak up” on producers is important at this time of the season. Small problems can turn large quickly at this time of the season.

Aaron Saeugling: We have seen no precipitation in the last week and crops are showing signs of stress from limited root growth and temperatures over 90°F and windy conditions. Corn is rolling to conserve moisture in some fields. Corn is closing the rows and most side-dressing and herbicide applications are complete in this area. Soybeans look good with weed control as the number one issue for this week. Waterhemp is growing nicely, and may be a challenge for farmers who do not get it sprayed at the appropriate time. Forages look good despite needing precipitation.  

Clarke McGrath: Things looking better in west central and southwest Iowa, although Ringgold, Union, Adams, and Taylor counties and adjacent areas look pretty tough in spots. As you head north and west from those areas, things improve, but there are still a lot of thin spots and stunted corn and soybeans. Parts of Pottawattamie, Shelby, Audubon, and Crawford counties seem to be the best around the area.

Last week’s crop issues were finalizing our nitrogen (N) applications to corn--that is about done. Post corn spraying is about wrapped up too, with fewer drift and performance issues than expected, given the winds and small spray windows. Replant is pretty much done with a few guys putting some beans in the Missouri Valley river bottoms last week. Soybean spraying going full force despite the heat.

Mark Johnson: There are large, dry areas in each of my counties in central Iowa, with some compacted areas of fields looking tough. I’ve had a few calls on diseases or insects, and several calls on crop injury from herbicides or from herbicide drift. Photos below were taken in Marshall County.
  Cornfield in Marshall County           Cornfield in Marshall County
  Photos by Mark Johnson

East Central, Southeast, South Central
Rebecca Vittetoe: In general, the crops look pretty good in this part of the state. South central and southeast Iowa could definitely use some rain. What rain we have had has been pretty spotty with some isolated areas getting up to an inch of rain and others getting nothing. The corn is showing signs of stress by rolling the leaves. Sulfur deficiencies have started showing up, especially in lower organic matter soils as well as potassium deficiencies, particularly in compacted areas in a fields. Photo below was taken in Wapello County.

Photo by Rebecca Vittetoe

Meaghan Anderson: Corn is putting on leaves quickly with the warm temperatures, and soybeans are mostly between V3- V5.  Soybean postemergence herbicide applications are still going strong. With the warm temperatures, farmers should be careful to apply herbicides when weeds are actively growing. We’re dry in most of east central Iowa, but corn in counties to the south are really starting to show leaf curling. I’m getting a lot of phone calls about weeds that just don’t want to die; options are usually very limited with big weeds this late in the year.

Weeds in corn
Photo by Meaghan Anderson

Virgil Schmitt: We’ve had over 5.5 inches of rain in northern Jackson County, most of Dubuque County, and parts of Delaware County to none in parts of western Lee County. In general, less than 0.5 inch south of Highway 64 and more than 2.0 inches north of Highway 64. So far in June, Burlington has had 0.22 inches of rain.

Corn is V9-V12. Corn issues this past week involve low moisture along and south of I-80, sulfur deficiency symptoms, and light flag leaves due to rapid growth. Soybeans are in the V3-V5 growth state. For soybeans, I encountered a few cases of bacterial blight and septoria brown spot in the area, along with shorter plant growth from heavier residue. Oats are headed, but I haven’t seen any in the milk stage yet, and hay regrowth looking good. Other calls I’ve received over the past week involve herbicide drift, herbicide failure on waterhemp, and surfactant burn.

Find your local ISU Extension and Outreach field agronomist here!

Related links:
Iowa crop update for June 7 to June 12, 2016