Lep Monitoring Network – Black Cutworm and True Armyworm Update # 3

Week 3 of monitoring for black cutworm (BCW) and true armyworm (AMW) resulted in the highest statewide average for both pests so far this year. To monitor for BCW and AMW, wing traps are placed at the edge of corn fields and checked weekly through the end of May.

Black cutworm

Many counties in Ohio saw an increase in BCW adults from April 29 – May 5. The statewide average increased from 2.6 moths from April 22 – 28 to 5.2 moths this past week. Counties with the highest averages included Hardin (12.0) and Van Wert (10.8) (Figure 3).  Keep in mind, BCW adults are attracted to fields with broadleaf weeds, such as chickweed (Figure 1) and purple dead nettle (Figure 2), where they will lay eggs. Eggs 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. For more information on how to scout BCW please visit: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_35_14 BCW.pdf

Figure 1. Common chickweed. Photo credit: Curtis Young.

Figure 2. Purple dead nettle. Photo credit: Curtis Young.

Black cutworm moth map

Week 3 - April 29^th to May 5^th, 2024

Figure 3. Average black cutworm (BCW) moths captured from April 29^th to May 5^th. The bold number on the left indicates the average moth count for the week, followed by the standard number on the right which indicates the total traps set up in that county.

True Armyworm

Similar to BCW, the statewide average also increased over the past week for AMW from 7.3 moths to 9.4 moths, indicating moths remain active in Ohio. Counties with an average that increased over the past week include: Auglaize, Defiance, Henry, Lucas, Pike, Van Wert, and Wood counties. The counties with averages of 7 or more moths include: Van Wert (22.9), Henry (12.0), Wood (10.0), Auglaize (8.7) and Putnam (7.8) (Figure 4). 

True Armyworm moth map

Week 3 - April 29^th to May 5^th, 2024

Figure 4. Average true armyworm (AMW) moths captured from April 29^th to May 5^th. The bold number indicates the average moth count for the week, and the standard number in parentheses is the total number of traps set in that county.