The Ohio Lep Network is back for a fourth year of monitoring Lepidopteran pests in ag crops across Ohio. Similar to last year, we will be monitoring black cutworm (BCW), true armyworm (AMW), corn earworm (CEW), western bean cutworm (WBC) and fall armyworm (FAW) throughout the growing season.
To start off the year we have 15 counties monitoring for BCW and AMW. This is our first year using green bucket traps to monitor to BCW and AMW – in past years we have used wing traps. I want to note that using different trap types this year makes it difficult to compare moth numbers from previous years. Traps are placed along fields that will be planted to corn and monitored weekly for about 7 weeks. Last week was our first consistently warm week in Ohio and we did see our moth numbers spike especially in northwest and northern Ohio counties. Read more below for specific details.
Black cutworm
Over the past week BCW moth trap numbers were high in Ohio, with many monitoring counties reporting moths in their traps. Overall, we monitored a total of 43 traps in 15 counties. Our statewide average was 20.1 moths. We recommend keeping a close eye on fields in counties with averages of 7 moths or more, which included Auglaize, Defiance, Henry, Huron, Lorain, Van Wert and Wood (Figure 1).
Some information on BCW: The 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 specifically 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, and 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 1
April 21st to April 27th, 2025
True Armyworm
True armyworm was also monitored from April 21st to April 27th using 42 traps in 15 counties (Figure 5). Our statewide average for the week was 15.3 moths. Counties with a weekly average of 7 moths or more included: Auglaize, Henry, Lucas, Putnam, 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 map
Week 1
April 21st to April 27th, 2025
One more side note - in addition to BCW and AMW, our county educator in Van Wert also observed variegated cutworm activity beside a clover cover crop field and egg masses on some wing traps and telephone poles nearby (Figure 7). While we are not monitoring for variegated cutworm in our network, it is another Lep to keep an eye out for and confirms that females are active and laying egg masses in our area.
