2024 Iowa Moth Trapping Network Update: Week 8

May 29, 2024 9:24 AM
Blog Post

Moth flights into Iowa were drastically reduced during Week 8 (May 19 to May 25), partly because of fewer moths but also likely due to the fact that recent storms took out several traps across the state. Our cooperators recorded only 51 black cutworm (BCW) moths and, for the first time since Week 1, no significant flights were recorded.

Figure 1 shows where moth traps are established throughout Iowa and black cutworm trap captures by county. Figure 2 shows the maximum 2-night capture in each county. This is an important distinction because although total moth counts tell us a bit about moth activity in the region, we determine whether a significant flight has occurred based on total captures over two nights. The red coloration on both maps indicate significant flights occurred, but Figure 2 gives a better sense of where large flights occurred even if they were not significant.

BCW Counts May 19 to May 25 2024
Figure 1. Black cutworm moth captures from May 19 to May 25. 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; highlighted counties without numbers indicate that traps are placed but no reports have been received). The number in parenthesis represents the season-long total black cutworm captures in that county. Data is current as of May 29, 2024.

Maximum 2-night count of BCW May 19 to May 25 2024
Figure 2. Maximum two-night moth captures in each county during Week 8 (May 19 to May 25). Increasingly intense colors indicate more moths were captured over a two-night period during the week.

Since BCW moths are still arriving in Iowa, plan to scout corn until the V5 growth stage. Look for missing or cut plants, and refer to this encyclopedia article to help make management decisions. First cutting dates have already been posted, but continued flights into Iowa could mean a prolonged risk of black cutworm to seedling corn.

Follow the links to see reports from Week 1, Week 2, Week 3, Week 4, Week 5, Week 6, and Week 7. You can also track moth flights, black cutworm significant flights, and projected cutting dates for Iowa, Illinois, and Wisconsin at 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:


Ashley Dean Agriculture and Natural Resources Extension Specialist II

Ashley is an education extension specialist for field crop entomology at Iowa State University. She 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 ...