Lep Monitoring Network – Black Cutworm and True Armyworm Update # 1

Our fifth year of the Ohio Lep Monitoring Network has officially started! This year we will continue o monitor Lepidopteran (moth) pests in agronomic crops across Ohio. Similar to last year, we will be monitoring 5 moth pests including black cutworm (BCW), true armyworm (AMW), corn earworm (CEW), western bean cutworm (WBC) and fall armyworm (FAW) throughout the growing season.

For our first update, we have nine counties that monitored for BCW and AMW from April 13 through 19. This is one week earlier than our first trapping report in 2025. To monitor, we are using green bucket traps. Traps are placed along field edges that will be planted to corn and monitored weekly for about 7 weeks. Last week the warm weather brought in numbers for both BCW and AMW. Read more below for specific details.

Black cutworm

Over the past week BCW moth had a range of averages from 0.5 moths to 34.0 moths. All of the  monitoring counties reported moths in their traps. Overall, we monitored a total of 26 traps in 9 counties. Our statewide average was 5.6 moths. We recommend keeping a close eye on fields in counties with averages of 7 moths or more, which included Defiance and Lucas (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 Table

Week 1

April 13^th to April 19^th, 2026

True Armyworm

True armyworm was also monitored from April 13^th to April 19^th using 26 traps in 9 counties (Figure 5). Our statewide average for the week was 9.7 moths, with the highest trap catch of 80 moths in one trap in Van Wert County. Counties with a weekly average of 7 moths or more included: Fayette, Lucas and Van Wert.

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 Table

Week 1

April 13^th to April 19^th, 2026