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The weather warmed up a bit during Week 5 (April 25 to May 1), and the moths were flying more than previous weeks. During Week 5 of the Iowa Moth Trapping Network, our cooperators reported 97 total black cutworm (BCW) and 33 true armyworm (TAW) moths.

A lot of planting progress was made for both corn and soybeans over the last week. According to the May 3 USDA-NASS Crop Progress Report, approximately 70% of Iowa’s corn crop has been planted and about 40% of the soybean crop. Iowa State University Extension and Outreach field agronomists share reports on what they are seeing and hearing in their respective regions across the state with field conditions and planting progress.

Northwest Iowa

Cooler conditions continued into week 4, resulting in relatively few moths being caught across the state. During week 4 of the Iowa Moth Trapping Network (April 18 to April 24), our cooperators reported 56 total black cutworm (BCW) and 15 true armyworm (TAW) moths.

Soybean research and Extension specialists from land-grant universities across the country welcome you to join a monthly informal discussion on production topics that have timely relevance. By joining the Notes from the Field webinar series, you will get highlights and current issues from across the major soybean growing regions of the U.S. You will have the opportunity to ask questions to guide you and your operation.

Schedule

Just last week, Ashley Dean predicted overwintering mortality of bean leaf beetle in Iowa. It looked pretty grim for this soybean pest, with over 77% mortality predicted for central Iowa. I didn’t have high hopes for a new insecticidal seed treatment study going in at the ISU Johnson Farm just south of Ames. While we were getting ready to plant today, it started to rain just a bit, too.

Like in prior springs, we often see a trend in the weed identification questions in certain parts of the state. This spring, a small mustard species with finely-divided (I like to say frilly or lacy) leaves is the most frequent plant requiring identification by our clients. There are several species we may run into in the spring with these lacy or finely-divided leaves. I’ve outlined the species in question, Descurainia species, and a few others that could look similar.

It’s been an unusual spring with the cooler and drier conditions. While many would welcome a rain, the warmer conditions mean planting has gotten underway. Iowa State University Extension and Outreach field agronomists share reports on what they are seeing and hearing in their respected regions across the state with field conditions and planting progress.

Northwest Iowa

While the warm weather has finally arrived for planting season, dry soil is becoming an increasing concern in parts of the state. In addition to concerns about subsoil moisture, some fields have had significant surface drying, particularly in areas with more tillage this spring. Dry soil conditions have put into question seeding depth. The goal here is to plant the seed into moisture to achieve uniform emergence.

Soybean seed depth considerations

During week 3 of the Iowa Moth Trapping Network (April 11 to April 17), our cooperators reported 62 total black cutworm (BCW) and 9 true armyworm (TAW) moths. Cooler conditions recently may have slowed down moth migration into the state, but black cutworm remains the dominant species caught in traps around the state.

The optimum rate of Nitrogen fertilizer application on corn varies from year to year and from field to field. Here we provide simulation data to aid decision making.

We simulated 25,000 fields across the U.S. Corn Belt from 1984 to 2021 using the Agricultural Production Systems sIMulator (APSIM). In this report, we benchmark Iowa soil N mineralization and N loss by crop reporting district.

The concern for not having enough water during the 2021 growing season is increasing. Observations from Iowa fields (i.e., deep soil samples and tile drainage experiments), and analytical frameworks (i.e., Drought monitor) indicate below normal moisture in parts of Iowa. Here, we benchmark the 2021 spring soil moisture across fields and across profile depths to enhance our understanding of current soil moisture conditions.

Subsoil moisture levels have improved for 2021 crop production.

Iowa State University has completed their spring survey of subsoil moisture in northwest Iowa, says Paul Kassel, ISU Extension and Outreach Field Agronomist located in Spencer.  The amount of subsoil moisture is sampled in the fall and spring in six northwest Iowa counties.

The Crop Protection Network (CPN) has produced a new web book called Fungicide Use in Field Crops. Fungicides are an important crop protection tool for modern agriculture, and proper use decreases risk of fungal diseases and economic losses. This book highlights the importance of fungicides for yield protection, while considering economics, risks to humans and the environment, and prolonging use of fungicide modes of action.

The 2021 Virtual Crop Scout School is now available and is free to the general public. The scout school consists of 22 webinars from crop protection specialists at eleven Midwest Universities and is offered through the Crop Protection Network (CPN).

It’s hard not to be itching to get in the field and start planting, especially since we are past the April 11^th crop insurance date for planting. However, the optimum planting date is dictated by soil conditions (moisture and temperature), the weather forecast, and the calendar date – not just one of these.

With cool weather conditions potentially causing delays in cover crop termination, what options are available? Cereal rye ahead of soybean is not nearly as problematic. While planting green may not be advised for beginning cover crop users, more experienced cover crop users have planted soybean into green cereal rye. There are two main considerations. First, make sure the planter is setup properly for the seedbed conditions.

Recent research showing the benefits of sulfur application to corn in Iowa have many folks asking questions about ammonium thiosulfate or ATS. ATS and ammonium sulfate (AMS) contain both nitrogen and sulfur, however in different amounts. AMS also differs from ATS in that all the sulfur in AMS is immediately available to plants in the sulfate form, whereas ATS contains no sulfur in the sulfate form, but changes to sulfate after application to the soil. 

While it seems like most alfalfa fields are greening up quite nicely this spring, there have been a few reports of winter injury in alfalfa stands, especially if stands or parts of stands may have been covered by sheets of ice during the winter.

Even though the weather has been variable this past week, one thing is certain: black cutworm is moving through Iowa. During week 2 of the Iowa Moth Trapping Network (April 4 to April 10), our cooperators reported 122 total black cutworm (BCW) and 21 true armyworm (TAW) moths. Windy conditions last week likely helped move so many moths into the state. Both species take advantage of powerful low-level jet streams at night to move long distances from their overwintering sites in the south.

Does the recent increase in nitrogen (N) cost and the increase in corn grain price warrant a change in nitrogen rates in 2021?  The following discussion gives an overview of the current N cost and corn price situation

New crop corn for delivery during the fall of 2021 was $4.05 per bushel locally on January 10, 2021.  And the price of a ton of anhydrous ammonia was $415 per ton the fall of 2020.