Lep Monitoring Network Update – True Armyworm vs Fall Armyworm, Trap Count Updates

True Armyworm vs Fall Armyworm— We all remember last year’s outbreak on alfalfa and forage from fall armyworm. Many growers are hearing “armyworm” again, and are worried about infestations in corn, wheat, oats and other small grains this spring. Keep in mind that we have two completely different species of armyworm:  True (or common) armyworm (Mythimna unipuncta) usually occurs in the spring (Figure 1A).  Infestations are typically found in wheat or oats, before marching onto corn and turf later in the season. Fall armyworm (Spodoptera frugiperda) usually occurs in late summer/early autumn and infests late stage corn and forages (like we saw last year) (Figure 1B). Neither species overwinters in Ohio—so any moths or caterpillars from last year did not survive. Both species migrate north from southern states. True armyworms arrive earlier and are more of a concern in the spring. Right now, the numbers in our true armyworm traps are variable but relatively low. Eleven counties monitored a total of 32 traps from May 16 – 22. All counties reported an average of less than 10 moths over the past week (Figure 2). Nonetheless, scouting of small grains is encouraged—see our true armyworm fact sheet for further instructions: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_36_14%20Armyworm.pdf

Figure 1. A) True armyworm adult. Photo credit: Curtis Young. B) Fall armyworm adult. Photo credit: Curtis Young.

True armyworm moth map: May 16 - 22, 2022

Figure 2. Average true armyworm (AMW) moths captured from May 16^th to May 22^nd. The large number indicates the average moth count for the week and the small number in parentheses is the total traps set up in the county.

Black cutworm

We are currently in our fourth week of monitoring for the black cutworm (monitoring from May 16 – 22). Over the past week, a total of 33 traps in 12 counties were monitored. Wayne county reported the highest moth average at 13 moths for the past week (Figure 3). For more information about BCW please visit: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_35_14%20BCW.pdf

Black cutworm moth map: May 16 - 22, 2022

Figure 3. Average black cutworm (BCW) moths captured from May 9^th to May 15^th. The large number indicates the average moth count for the week and the small number in parentheses is the total traps set up in the county.

European corn borer

This is our first week monitoring for European corn borer (ECB). We will be monitoring for both ECB-IA and ECB-NY with delta wing traps in the field. Ten counties monitored for ECB this first week. All counties are currently reporting low numbers (Figure 4).

European Corn Borer moth map: May 16 - 22, 2022

 Figure 4. Average European corn borer (ECB) moths captured from May 16^th to May 22^nd. The first number indicates the average ECB-IA followed by a comma and then the average ECB-NY moth count for the week. The small number in parentheses is the total traps for each species set in each county.