While most areas received some needed rain last week, some areas in Western Iowa continue to miss out on the rain or get minimal amounts of rain and it’s starting to show more in the crops. Getting out in the fields, some pests or issues observed by ISU Extension Field Agronomists included corn rootworm larvae, Japanese beetles, stink bugs, herbicide damage, and some nutrient deficiencies. Read on for more specifics on what’s happening across the state.
Gentry Sorenson (Region 2): “Rainfall was variable across the counties that I cover in NW Iowa. Rainfall ranged from a trace to around 1 inch, with most areas receiving only a trace of rainfall. Corn growth stage is at V9, and soybeans range from V5 to V6. Many farmers are working on finishing up with POST herbicide applications in soybeans. Overall, the crop is looking good, but we are seeing drought stress start to show up in some areas. The area that I cover in NC to NW Iowa is experiencing leaf rolling on corn in many counties. There were many field visits and phone calls over the last week, all of them were herbicide related and involved questions about herbicide drift onto soybeans and corn.”
North Central Iowa
Angie Rieck-Hinz (Region 3): “From June 20- June 27, rainfall was from 0.05 inch to 3.99 inches. Corn in areas of Humboldt, Webster, and Hamilton counties are exhibiting some stress due to dry conditions. GDD accumulation was on track for last week, but when calculating GDDs from April 11 until June 27, we are still running 2-3 days behind normal. Corn is V5 to V10. Soybeans are V4 to R1. POST-application of herbicides in soybeans continues, and while crop stage may be behind normal, the weeds are not. Effectiveness of some POST-applied products will be in question with the overly large waterhemp and marestail present in many fields. I am never surprised to see people row cultivating, but don’t you be surprised if I pull over to take pictures! Stalk borers are definitely on the move in north central Iowa, and I have received a couple of calls with concerns about grasshopper populations. The majority of phone calls and field calls of the past week were primarily dominated by weed and herbicide calls, with a few nitrogen side-dressing phone calls as well.”
Josh Michel (Region 5): “Finishing up POST herbicide applications and the start of alfalfa second crop harvest were the main activities being conducted last week. Over the past seven days, most of the region received 0.25 to 0.50 inch of rain, but some areas in Buchanan County received up to 4 inches of rain as some strong thunderstorms came through late Friday night into early Saturday morning. Thankfully there wasn’t any reported crop damage. Most of the corn in NE Iowa can be staged from as small as V2-V3, up to V8 in some early planted fields. Soybeans can be staged from V2 up to V4-V5, with some early planted fields possibly flowering sometime later this week. POST herbicide applications have been getting finished up for both corn and soybeans. Almost all of the oats I’ve seen are headed out and a few fields are starting to turn. Alfalfa second crop harvest is underway in many areas as I’m starting to receive some reports of potato leaf hopper feeding. Pastures continue to benefit from the light rain showers, but warm temperatures have greatly slowed down the growth of many grasses. Recent field calls and questions have consisted mainly of alfalfa pests and scouting, small grains and forage management, possible nutrient deficiencies in corn and soybeans, and herbicide injuries due to spray tank contamination, product mis-use or suspected group 4 herbicide injury.”
Meaghan Anderson (Region 7): “Central Iowa received decent rainfalls through most of my counties last week; most of the area got over 0.5” and continued rainfall like that will be important as we approach reproductive stages in the coming weeks. Corn is mostly in the V7-V12 range and is looking more even and green than last week. Soybeans are in the V4-V6 range but many fields are beginning to flower and will soon be at R1 if not already there. In my western counties, both crops have suffered from flooding and ponding that still plagues some fields. I’ve received a lot of questions about sidedressing nitrogen in the last week, which is especially relevant as April 1 to now rainfall has been significant in Dallas, Boone, and Story counties (see “Springtime Precipitation – A Tool for Estimating Nitrogen Application Need for Corn”). Last week was also the first opportunity to replant some soybeans in drowned out areas as waters finally receded enough. POST herbicide applications are wrapping up and field calls have mainly centered around crop injury related to herbicides – misapplications, drift, weather-related issues, and carryover have all been present.”
Aaron Saeugling (Region 10): “Crop growth continues to progress. Corn is in the late vegetative stages while soybeans are catching up after a later planting date and isolated hail events across parts of SW Iowa. Corn rootworm larvae feeding has been observed in some fields. Soybean gall midge emergence is occurring now, but I have not heard any reports of damage yet. Start scouting for other insects like Japanese beetles over the next few weeks. Herbicide spraying continues with various crop stages and planting dates. I expect to see tassel emergence and soybeans flowing in the next week to 10 days. We have made good crop progress given the later than average planting this year.”
East Central, Southeast, and South Central:
Rebecca Vittetoe (Region 8): “Last week you could really start to see corn leaves rolling, especially in the afternoon, across my area. Thankfully we did receive some much-needed rain last week. Rainfall totals ranged from a couple tenths to 6 plus inches in some isolated areas (mainly between Iowa City and Cedar Rapids area). Most corn falls within the V7-V11 growth stage and soybeans V4-V7. I noticed later last week some soybean plants starting to flower here and there in fields. POST applications are starting to wrap-up in soybean fields. I saw my first corn rootworm larve feeding on corn roots last week and noted seeing Japanese beetles as well. The majority of my questions were herbicide related last week with a lot of herbicide injury (drift, wrong product sprayed on the field, or tank contamination)."
Virgil Schmitt (Region 9): “Rainfall last week in the counties I cover was extremely variable, ranging from a trace to over three inches. In general, temperatures during the last week in the counties I cover were two to six degrees above normal. Most corn is V8-V10 and looks good to excellent. A few fields have severe infestations of stink bugs and are being treated with an insecticide. Most soybeans are at V4-V6 and also look good to excellent. I have not seen any blossoms yet, but I am sure there are some fields with blossoms. Potato leafhoppers are present in alfalfa. There are numerous grasshopper nymphs in some grassy areas. Phone calls and field visits last week mostly involved herbicide injury (including wrong product in the genetics planted), herbicide drift, herbicide lack of performance, and stick bugs.”
Check out the map below to find your local ISU Extension field agronomist and find their contact information here!