2022 Iowa Moth Trapping Network Update: Week 4

April 28, 2022 12:56 PM
Blog Post

Black cutworm (BCW) and true armyworm (TAW) moths continued to migrate into Iowa during Week 4 (April 17 to April 23). Last week, our cooperators reported a total of 60 BCW and 13 TAW moths throughout the state.

Week 4 report:

All of the moths were captured in the late part of last week (April 20 to April 22), with 12 TAW and 33 BCW captured on Friday, April 22. Two significant flights of BCW occurred on April 22: one in Buena Vista County (northwest) and one in Mills County (southwest). So far this spring, significant flights have been reported in Buena Vista, Mills, and Taylor (Week 3) counties. Figures 1 and 2 show the Week 4 trap reports for true armyworm and black cutworm, respectively.


Figure 1. True armyworm moth captures from April 17 to April 23. The bold number indicates the total moth count for the week (for counties with multiple sites, only the site with the highest total 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 April 28, 2022.

BCW reports April 17 to 23 2022
Figure 2. Black cutworm moth captures from April 17 to April 23. The bold number indicates the total moth count for the week (for counties with multiple sites, only the site with the highest total 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 April 28, 2022.

Follow the links to see reports from Week 1, Week 2, and Week 3. You can also track moth flights and black cutworm significant flights for Iowa, Illinois, and Wisconsin on https://corn.ipmpipe.org/insects/. In a few weeks, we will begin predicting cutting dates for Iowa, which will be posted on the corn IPMpipe website and ICM News.

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. I will predict cutting dates across the state by mid-May and share them on ICM News, so make sure you are subscribed!

Author: 

Ashley Dean Education Extension Specialist I

Ashley is an education extension specialist for field crop entomology at Iowa State University. She coordinates the Iowa Moth Trapping Network, develops educational resources for field crop pests in Iowa, and aids in the research efforts of the