Soybean gall midge larvae, Japanese beetles, foliar diseases in corn, and weed management issues were some of the more common issues ISU Extension and Outreach field agronomists came across in fields this past week. Read on for more information about what’s happening in specific regions across the state.
Joel DeJong (Region 1): “In the NW corner of Iowa we see a wide range of corn growth. Early planted corn is around the V13 stage, and I estimate it is about 10 to 14 days from tasseling. Some of the June planted corn is about V6 to V7, and still somewhat showing that striping of the inability to get roots into the fertilizer. I am always amazed how rapidly corn grows when the system is well established, moisture is available, and average temperatures for early July are present! Soybeans are beginning to flower in many fields, although the latest planted ones are not that far along yet. Soybean gall midge larvae damage became more evident in many NW Iowa counties this past week. It has been interesting that I have also been asked about stalk borers in soybean field edges this year several times, too – an outgrowth of observing what annually happens, but noticed more when looking for other pests. Post soybean spraying continues. It will be interesting to see if the big weeds present in some fields can be controlled or only set back.”
Paul Kassel (Region 2): “Crop development continues to progress. A recent trip to Palo Alto County, which was an area that had good planting progress this spring, showed a lot of corn in the V12 stage and soybeans in the V8 to R2 stage. We will likely start to see a few tassels in this early planted corn around the last week of July. That is the good news; however, the rest of my area had a fair amount of corn planted in early June. This early June planted corn is developing at a good pace but is in the V7 to V8 stage currently. Farmers in Clay County that had hail damage from the June 27 hail event are still evaluating options. There will be some replanting of the soybean crop – although that activity has been delayed by some decent rain amounts during the 4th of July weekend. Other farmers are considering small grains or millets for cover crops and or forage crops, and they are finding that supplies of these forage crops are in short supply."
Meaghan Anderson (Region 7): “Much of central Iowa got some rain last week, but some areas missed virtually all the rain and could use a nice rain. Corn root systems seem fairly shallow and some are really suffering from the conditions at planting time. With the rain last week, the western reaches of my area (Boone, Dallas, and Madison Counties) received some wind that caused root lodging in corn and a very small amount of green snap. Most corn is very close to tassel, so farmers should be scouting for foliar disease and keep an eye on insect activity as reproductive stages near. Japanese beetles are out and will be highly attracted to silks in corn, but they aggregate along field edges, so scout thoroughly before treating. Corn rootworm beetles should be out as well; high numbers are a good sign that there may be significant feeding on roots below ground, but the only way to know for sure is to dig the roots! Many soybean fields are now in reproductive stages (flowering) and many soybeans in narrow rows have filled in the open row space. Most recent contacts have been about corn as a cover in prevented plant fields, herbicide options for July applications in soybean, and cleaning up large weeds in fields.”
Southwest and West Central
Aaron Saeugling (Region 6): “Early planted corn is in the late vegetative stages and looks very good. There were some isolated spots in Adams and Union Counties of heavy rain and wind damage from a July 3rd storm. Soybeans are all over the board with early planted beans beginning to flower (R1). Weed control is an issue in fields with large weeds, especially where burndown applications were not applied prior to planting. Insects dominate the conversation in the coffee shops with painted lady butterflies (adult thistle caterpillars) everywhere. We also have an outbreak of soybean gall midge larvae damaging soybeans in fields adjacent to last year’s soybean fields where damage from soybean gall midge larvae was observed. Farmers need to be scouting fields in SW Iowa, especially west of US HWY 71 for soybean gall midge larvae. Japanese beetles are also being reported causing defoliation damage in soybean fields. Alfalfa fields look good and good yields have been reported.”
East Central, Southeast, and South Central
Rebecca Vittetoe (Region 8): “Corn ranges from V13 to V14 down to V5 to V6. I’ve noticed a few of the earlier planted fields with some tassels starting to poke out. I’ve also started to notice some gray leaf spot lesions and common rust appearing in corn fields. As we approach the reproductive stages in corn it will be important to scout for foliar diseases. Over the weekend some of the later planted corn fields did show signs of moisture stress, and could benefit from some rain. Soybeans range from R2 down to V2 to V3. Insect pests that can be found in soybean fields include Japanese beetles and first-generation bean leaf beetles. I’ve also started to notice bacterial blight in some soybean fields. Many are taking the second cutting of hay. Weed management, herbicide drift, foliar diseases in corn, and cover crop options for prevent plant fields were some of the common questions over the last week.”
Virgil Schmitt (Region 9): “Rainfall last week was from less than 0.5 inch (roughly south of HWY 92) to between 0.5 and 2.0 inches (roughly north of HWY 92) with some areas receiving between 2.0 and 3.0 inches in thunderstorms. Field work days last week ranged from zero to seven, depending on location. April planted corn is mostly V13 to V14, mid-May planted corn is mostly V11 to V12, and June planted corn is mostly V7. Post herbicide applications are wrapping up. There was some corn leaf rolling due to moisture stress on some hot days last week, even in fields where soil moisture was abundant; there wasn’t a large enough root system to be able to move water into the plant fast enough. Soybeans range from R2 down to V2. Post herbicides are being applied. There was quite a bit of hay harvesting activity last week where weather allowed. Japanese beetles are becoming very evident and there is European Corn Borer shot holing in some corn. Inquiries about weed management, herbicide use, herbicide injury, and cover crops continued to dominate calls last week.”
Josh Michel (Region 11): “Much of southern Iowa received anywhere from just a tenth up to half an inch of rain last week, with some isolated areas receiving up to one inch. The dry weather allowed many field operations including some much-needed post herbicide applications to be completed. The dryer weather is supposed to continue, which will be a great opportunity for many second hay cuttings to get completed. April planted corn is V13 to V14, while June planted corn is around V6 to V7. I expect to see some tassels by this weekend on the earliest planted fields. Soybeans range from V3 up to R2. Japanese beetles are causing some concerns with defoliation in some of the younger soybean fields. I’m starting to get more questions about herbicide injuries that are starting to show-up in soybean fields as well. Common questions this past week have been on nitrogen management, fungicide use in corn and soybeans, late season weed management, summer forages, and prevented planting options.”
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