Our second week of monitoring for black cutworm (BCW) and true armyworm (AMW) is complete! Green bucket traps were monitored in 14 counties across Ohio from April 20th – 26th. Traps are placed along the edge of fields planted to field corn. The weather over the past week was a mix of warm/cold and rainy – and resulted in increased numbers of BCW and AMW. For more specific information, see below.
Black cutworm
Over the past week BCW moth had a range of averages from 0 to 32.0 moths. Overall, we monitored a total of 38 traps in 15 counties. Our statewide average was 8.8 moths which is higher than 7.0, the number that we recommend keeping a close eye on fields. The counties that had averages of 7 moths or more included Defiance, Fulton, Henry, Lucas, Madison and Van Wert (Figure 1).
Black cutworm moths are dark brown to black with a small black dagger mark two-thirds of the way toward the outer edge of the wing (Figure 2). Adults are attracted to fields with broadleaf weeds, such as chickweed (Figure 3) and purple dead nettle (Figure 4). The moths will fly into these area and lay eggs, which then hatch in 5 – 10 days. Once hatched larvae go through 6 instar stages over the next 28 – 35 days. Counties with high trap numbers should plan to scout for BCW larvae after corn is planted until V6 stage, especially in fields with a lot of broadleaf weeds (such as chickweed and purple dead nettle). For more information on how to scout BCW please visit: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_35_14 BCW.pdf
Black Cutworm Moth Map
Week 2
April 20th to April 26th, 2026
True Armyworm
True armyworm was also monitored last week with 35 traps in 15 counties (Figure 5). The statewide average for the week also increased slightly to 9.8 moths (up from 9.7 moths for the week of April 13th). Most of the moth activity we are seeing is in northwest Ohio. High trap averages for the week include Fulton (60.0), Henry (20.0), Lucas (31.0) and Van Wert County (21.1). Again, we suggest that counties with a weekly average of 7 moths scout for AMW larvae in the coming weeks. This week, Lucas and Van Wert had averages higher than 7.0.
Adult AMW are tan to reddish brown and have a single white mark in the center of their wing (Figure 6). Adults lay eggs in grasses and rye cover crops. The eggs hatch and the feed on young corn plants. Counties with high trap numbers should monitor for AMW larvae after corn is planted, especially in areas of grassy no-till fields or fields that had rye cover crop.
True Armyworm Moth Map
Week 2
April 20th to April 26th, 2026
Additional Author: Hannah Houser