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2022 Iowa Moth Trapping Network Update: Week 7

May 18, 2022
Content Author: Ashley Dean

Last week, moth flights into Iowa were slightly lower than previous weeks. In total, our cooperators captured 55 true armyworm (TAW) moths and 102 black cutworm (BCW) moths during Week 7 (May 8 to May 14).

Week 7 report

Moths of each species were captured almost every day last week, and reports were relatively consistent throughout the week. No additional significant flights of BCW occurred during Week 7, but we predicted cutting dates based on previous significant flights, degree day accumulation, and historical weather data. Figures 1 and 2 show the Week 7 trap reports for true armyworm and black cutworm, respectively.

TAW reports May 8 to 14 2022
Figure 1. True armyworm moth captures from May 8 to May 14. The bold number indicates the total moth count for the week (for counties with multiple sites, only the site with the highest weekly moth count is reported), while the smaller number in parentheses is a running total of the moth count for the season; highlighted counties without numbers indicate that traps are placed but no reports have been received. Data is current as of May 18, 2022.
BCW reports May 8 to 14 2022
Figure 2. Black cutworm moth captures from May 8 to May 14. The bold number indicates the total moth count for the week (for counties with multiple sites, only the site with the highest weekly moth count is reported), while the smaller number in parentheses is a running total of the moth count for the season; highlighted counties without numbers indicate that traps are placed but no reports have been received. Data is current as of May 18, 2022.

Follow the links to see reports from Week 1, Week 2, Week 3, Week 4, Week 5, and Week 6. You can also track moth flights, black cutworm significant flights, and projected cutting dates for Iowa, Illinois, and Wisconsin on https://corn.ipmpipe.org/insects/.

Surrounding states also monitor and report BCW and TAW captures. If you live near the state border, it may be beneficial to check these resources periodically. More resources may be available than what is listed here:

What is a significant flight? A significant flight of BCW occurs when 8 or more moths are captured over a two-night period; this serves as the “biofix” for degree-day accumulation and indicates an increased risk of black cutworm injury in corn. A degree-day model for black cutworm development predicts that larvae are large enough (4th instar or larger) to cut corn plants once 300 degree days (base 50°F) have accumulated since a significant flight occurred. Cutting dates have been predicted for Iowa: https://crops.extension.iastate.edu/cropnews/2022/05/begin-scouting-black-cutworm-corn.

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on May 18, 2022. The information contained within may not be the most current and accurate depending on when it is accessed.

Authored by
Ashley Dean
Ashley Dean
  • Extension Education Specialist, Entomology
Ashley is an extension specialist for field crop entomology at Iowa State University. Ashley coordinates the Iowa Moth Trapping Network, the Regional Corn Rootworm Monitoring Network, and the Iowa Pest Alert Network. She also develops educational resources for field crop pests in Iowa and aids in the research efforts of the Soybean Research Laboratory.

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