Lep Monitoring Network – Black Cutworm and True Armyworm Update # 5

After finishing out our fifth week of monitoring for black cutworm and true armyworm, it was observed that the slight decline seen last week in the statewide average for both pests has continued to drop. Van Wert has seen the highest average of both BCW and AMW pests this past week. These numbers indicate that we have most likely passed the peak abundance of both BCW and AMW moths in Ohio for this season.

Black cutworm

The statewide average decreased significantly from 4.2 during the week ending May 12^th to 2.7 for the week ending May 19^th. Counties with the highest averages included Van Wert (5.5), Putnam (4.5) and Hardin (4.0) (Figure 1).  As mentioned in last week's newsletter, adult moths lay eggs that hatch in 5 – 10 days. The 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

Black cutworm moth map

Week 4: May 13^th to May 19^th, 2024

Figure 1. Average black cutworm (BCW) moths captured from May 13^th to 19^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 number of active traps set up in that county.

True Armyworm

Similar to the trend seen in BCW this past week, the statewide average decreased for AMW from 8.0 moths for the week ending May 12^th to 2.1 for the week ending May 19^th. Counties with the highest averages this week included Van Wert (5.1), Defiance (3.3) and Hardin (3.0) (Figure 2).  As previously mentioned, plan to scout fields after corn is planted in counties that have had high averages, especially in fields that were previously planted to cover crops. 

True Armyworm moth map

Week 4: May 13^th to May 19^th, 2024

Figure 2. Average true armyworm (AMW) moths captured from May 13^th to May 19^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 number of active traps set up in that county.