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Due to 2023 court decision, questions continue about the use of chlorpyrifos on agricultural crops for 2024. The following chlorpyrifos products may be used on corn and soybean according to label directions and uses. This list was current as of July 17, 2024, and will change over time. Please refer to the listing of all chlorpyrifos products currently registered for use in Iowa for up-to-date information.

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Hail and wind damage, corn rootworm, Japanese beetles weed escapes, insect, and questions on foliar fungicides have been the more common issues or questions Iowa State University Extension and Outreach field agronomists have seen or heard about over the last week. Read on for more specifics about what’s happening around the state.

With all the talk on fungicide use in corn and soybean, this may be a good time to talk about alfalfa production and fungicide use. We often get asked as Extension field agronomists about studies conducted with fungicides on crops. So, the short answer to fungicide use on alfalfa is “it depends”, but we have good research on helping farmers understand when to put the odds in their favor. 

To read the rest of the blog and learn more about weather notables in Iowa, follow this link. 

Last week a beekeeper contacted me about a total bee kill as a result of the adjacent soybean field being sprayed with an insecticide. The applicator was not aware of the presence of the bee hives, even though the hives were registered on  the FieldWatch® (https://fieldwatch.com/) Beecheck (https://beecheck.org/) apiary registry.

As corn approaches tasseling, I hear more and more rumblings about fungicide application.  The good to abundant moisture we have had this growing season, has resulted in some itchy trigger fingers. In addition, the early reports of tar spot haven’t helped with the itch.  Do we need to scratch that itch and get a fungicide application on a.s.a.p? Here are some of my thoughts:

Hail and wind damage to crops, corn rootworm, nutrient deficiencies, herbicide injury/drift, and  waterhemp surviving post herbicide applications were common issues or questions reported by Iowa State University Extension and Outreach field agronomists over the last week. Read on for more specifics about what’s happening in fields across the state.  

Corn is beginning to tassel and there are fields with small ears, which means pollination is just around the corner. Corn pollen is highly attractive to many insect pests, so it is a good idea to assess pollination rates once reproductive development starts. This could be especially complicated in areas or fields with staggered planting dates and growth stages of corn. Some of the main silk-feeding insects in Iowa field corn are Japanese beetle, corn rootworm adults, and grasshoppers.

I’ve received several phone calls in the last couple weeks regarding waterhemp or other species that survived postemergence herbicide applications (in some cases, more than one!). While most herbicide applications have finished, it isn’t too late to evaluate how well your program worked, whether fields would benefit from a “last ditch effort” to reduce weed seed production, and what changes might be necessary for next year.

Flooding or flood damage in parts of Iowa, corn starting to tassel, corn rootworm, potato leafhoppers, waterhemp suriving post herbicide applications, and herbicide injury due to carryover or drift were "highlights" Iowa State University Extension and Outreach field agronomists saw over the last week. Read on for more specifics about what’s happening in fields across the state.  

Many areas in Iowa were impacted by hail this past week. Hailstorms are an unpredictable and formidable adversary for producers, capable of inflicting significant damage on crops, forage, and livestock. The impact of hail can be extensive, from shredded leaves to battered stems and bruised animals. However, there are strategies and solutions that can help assess and mitigate the damage and pave the way for recovery.

I've noticed potato leafhoppers in soybean this week (nymphs and adults), plus several notable observations are coming my way. It's time to get out a sweep net to  alfalfa and soybean so you can make timely treatment decisions. Depending on where you are in the state, you might be close to the second cutting or a few weeks away. It is important to distinguish leafhopper injury, sometimes called hopperburn, from other issues in the field. 

Recent floods throughout Northwest Iowa have caused significant damage and loss to communities, homes, roads, livestock producers, crops and more. Unfortunately, this situation will continue long after the rain as high river levels continue to surge south.

Heavy rain across northern Iowa resulted in major flooding in areas. For those dealing with flooding, additional resources can be found here ranging from farm and home to cleaning up after flooding. Read on for more specifics about what Iowa State University Extension and Outreach field agronomists saw over the last week.

Heavy rainfall can have economic and environmental consequences if flooded fields are left barren. Long-term damage to soil needs to be considered when planning for next season's crop.

Biological, chemical and physical soil health

The torrential rains that northern Iowa experienced last week may have favored several diseases of corn including crazy top, Physoderma brown spot and node rot, Goss’s wilt and bacterial stalk rot. While there are no in-season management practices for these diseases, correct diagnosis can help with disease management options in future years including choosing hybrids with resistance.

Crazy top

European corn borer, known as “the billion-dollar bug,” was a pest of economic concern in the United States prior to the commercialization of Bt corn hybrids in 1996. With the widespread adoption of Bt traits, European corn borer populations have been effectively managed and areawide suppression provided benefits to farmers that did not use Bt.

Summer annuals are valuable to forage production systems due to their heat and drought tolerance. These high-yielding crops are typically ready for grazing within 40-45 days under optimal conditions, making them ideal for double cropping systems. They provide excellent options for silage, baleage, hay, and grazing.

Areas in Iowa remained on the drier side last week while other areas received some heavier rain and even some isolated large hail in areas. Herbicide injury, Asian copperleaf, tar spot, nitrogen management, and weeds surviving herbicide applications were some of the hot topics or issues Iowa State University Extension and Outreach field agronomists saw over the last week. Read on for more specifics.