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Windy conditions last week (April 14 to April 20) brought a lot of black cutworm (BCW) moths into Iowa. A total of 157 BCW moths were reported by our cooperators during Week 3. April 17 had the most total moths reported (50 moths), but captures were consistent throughout the week. Ten significant flights occurred last week, and two sites had multiple significant flights during the week:

I’ve been scouting several alfalfa fields in East-Central Iowa this spring, and it’s always interesting to see what you get in your sweep net. While I’ve been able to find quite a few alfalfa weevil adults and larvae in fields this spring, that’s not all I’ve found!

Recent rains, cooler temperatures, and the windier conditions have slowed field activities. According to the May 22 NASS Crop Progress Report, 13% of the corn acres and 9% of the soybean acres have been planted. Some of the first planted corn and soybeans have emerged or are getting close to emerging.

Proper spray nozzle selection plays a key role in effective pesticide applications. There are a lot of useful sprayer nozzle selection guides and even online resources or apps to assist with nozzle selection. 

Wearing personal protective equipment (PPE) is your first line of defense against pesticide exposure. PPE includes  items such as gloves, coveralls, aprons, and respirators. Generally, as the toxicity of a pesticide increases, the more PPE items there are required.

Anyone working with pesticides is legally required to follow all PPE instructions that appear on the pesticide label.

Moth counts ramped up dramatically during Week 2 of the moth trapping network (April 7 to April 13), although we often get large flights with spring storm systems in April. Despite the low captures reported during the first official week, 70 total black cutworm (BCW) moths were reported last week. Most of those captures were reported on April 8 (41 moths), and 16 additional moths were reported on April 11.

Timing is crucial for spring planting. Planting too early can expose young stands to damaging frost, while planting too late can lead to greater potato leaf hopper and weed pressures.  Establishing a vigorous alfalfa stand is pivotal for future production, forage quality, and minimizing weed pressures. Here are some recommendations to establish a vigorous alfalfa stand.

Field Site

On May 16^th, we will be hosting a Field Crop Scout School at the Southeast Research and Demonstration Farm (3115 Louisa-Washington Rd., Crawfordsville, IA). Check-in begins at 8:30 a.m., with the program running from 9 a.m. to 3:30 p.m.

Given the dry conditions that prevailed Iowa in 2023, there will be herbicide carryover in 2024. Suspect herbicides that are likely to carryover include, but are not limited to atrazine, clopyralid, and the various HPPD inhibitor herbicides. Specifically, the accuracy, evenness, and timing (i.e., later in the season) of the 2023 herbicide applications can increase the potential for interactions with the 2024 herbicides.

Iowa soils can hold 9-12 inches of water in the soil profile and most parts of Iowa have shallow water tables at about 4-7 feet depth. These two sources of water, together with the precipitation, provide water for crop production. Typically, a 250 bu/ac corn yield requires about 22 inches of water as evapotranspiration.

Planting, in my opinion, is THE most important field operation. Planting in the optimal planting window and into good seedbed conditions will set the plant up for rapid growth and high yield potential. With planters beginning to move or sitting in waiting for better conditions, here are some planting considerations to consider.

Compared to March, April temperatures have so far stayed much closer to normal. So far, no days in April have exceeded 10°F above normal. The 30-day average temperature has been from 35-50°F.

I have been observing, and also receiving phone calls and e-mails about, purple weeds in untilled fields. If you observe such an area, the weeds are probably either purple deadnettle (Lamium purpureum) or henbit (Lamium amplexicaule) or a mixture of the two. They are very similar in appearance and growth habit, so you need to “get up close and dirty” to differentiate between them.

A few more farmers are switching to a high-speed planter when upgrading or trading planters.  A few reasons they report for switching to the high-speed planter include:

The 2024 moth trapping season is underway, and our volunteers began placing traps the week of March 24. Black cutworm (BCW) monitoring is a long-standing project in Iowa to detect moths migrating from southern overwintering sites each spring. By monitoring adult black cutworms, we can provide scouting recommendations to growers to avoid significant injury from black cutworm larvae.

It is important to read and follow all label instructions before applying a pesticide to insure you are following all measures to protect plants and animals, including federally listed threatened and endangered species. The label may instruct you to comply with Environmental Protection Agency (EPA) procedures or other regulations and requirements regarding the use of the pesticide product.

Over the last 10 days, precipitation totals across the state have varied with less precipitation falling in the western and northern part of the state and heavier amounts falling in the east-central and southeast part of the state.

With the recent precipitation, we are seeing improvements in drought conditions across the state. Below is a comparison of the U.S. Drought Monitor on March 5 (left) to April 4 (right).

With the announcements of water usage restrictions in parts of Iowa, pesticide applicators may need to use alternative water sources for their pesticide applications. Keep in mind the considerations below when using water from a new source this spring. For more information on these concerns, check out the Purdue University Extension publication “The Impact of Water Quality on Pesticide Performance,” available as a free download.

The visible and invisible

During the past 90 days, temperatures have been warmer than average, keeping soils from freezing and allowing much needed precipitation to infiltrate into the soil. Despite accumulated precipitation across the state being greater than average for the past 90 days, soil moisture is still lacking. Stream flow was below normal for most of the state during March into early April.

AMES, Iowa – Planting season varies wildly from year to year and technology is always changing. Cool and wet conditions can dramatically delay planting. When soil conditions are remarkably dry, getting seed in the soil at the correct depth is a challenge. But just as each planting season is different, so too are the decisions for optimizing the planting technology.