Introduction

The Ohio LEP Network is continuing to monitor moth pests across Ohio counties. For our fourth week of monitoring, we are reporting the numbers for black cutworm (BCW), true armyworm (AMW), and European corn borer (ECB) IA & NY moths across Ohio. Both BCW and AMW are considered early season pests, so our moth numbers for these pests is decreasing, as expected and the laval stages may be present in fields now. These insects’ larval stages are common pests in Ohio and can cause problems for farmers, specifically dealing with crop health and yield. If you are looking for more resources on these pests, check out our website: https://aginsects.osu.edu/

Beginning with Black Cutworms

We continue to monitor for BCW adults (Figure 1), as they have been our most prevalent pest reported across Ohio this summer. Counties with high trap numbers should continue to monitor for BCW larvae after corn is planted, with particular attention to fields with broadleaf weeds such as chickweed and purple nettles, as these are prime sources of food for BCW (Figure 2 and Figure 3) For more information about BCW please visit: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_35_14%20BCW.pdf

Over the past week, 10 counties monitoring 31 traps reported BCW numbers (Figure 4). Overall, the statewide average of BCW moths decreased from an average of 4.1 moths last week to an average of 2.3 moths this week. Hardin County was the only county with an average moth count above 7 from May 22^nd to May 28^th (11 moths, respectively). The county that had the most moths caught in just one trap was also Hardin County, with 18 moths in one trap.

Figure 1. Black cutworm moth (BCW) featuring a distinct dagger shaped marking on the forewing (circled in yellow). Photo Credit: Curtis Young.

Figure 2. Chickweed, one of the food sources for black cutworms. Photo Credit: Curtis Young.

Figure 3. Purple nettles, one of the food sources for black cutworms. Photo Credit: Curtis Young.

Black Cutworm Moth Map: May 22 – 28, 2023

Figure 4. Average black cutworm moths captured from May 22^nd to May 28^th..The bold number on the left indicates the average number of moths captured. The second number on the right indicates the number of traps monitored in each county. The darker green color indicates a moth average higher than 7 moths per trap.

Tackling the True Armyworm

We have entered our fourth week of monitoring for the true armyworm (AMW) (Figure 5). From May 22^nd to May 28^th, 11 counties across Ohio monitored for AMW, with 31 total wing traps being set (Figure 5). Similar to BCW, the statewide AMW moth average decreased over the past week, from an average of 2.7 the week of 15^th to an average of 1.3 moths this week. This week, our most significant county was Hardin County with an average of 5.3 moths per trap, which is a decrease from last week, with other counties reporting small average moth counts.

Figure 5. True armyworm moth displaying the light tan color, and white dot on wings (circled in yellow). Photo Credit: Kylie Harbert.

True Armyworm Moth Map: May 22 – 28, 2023

Figure 5. Average true armyworm moths captured from May 22^nd to May 28^th. The bold number on the left indicates the average number of moths captured. The second number on the right indicates the number of traps monitored in each county.

Encounters with the European Corn Borer

The European Corn Borer (ECB) is a common corn pest in Ohio that bores into corn stalks which disrupts the flow of nutrients in the corn stalks; which can increase corn stalk disease and stalk breakage, resulting in reduced corn yield. Unlike BCW and AMW, European corn borers overwinter in Ohio in corn stalks, and then emerge as moths in the springtime. These moths then deposit eggs on the underside of corn leaves, where the larvae will then hatch and feed on the corn foliage, before entering the stalk, causing damage to the corn stalk. The ECB moth is white, with a darker head and body area (Figure 6).  There are various types of ECB, and we monitor for the IA and NY variations. This is our second week of monitoring, and only ECB-IA variation has been reported these past two weeks. Seven counties monitored for ECB over the past week and only ECB-IA was reported. (Figure 7). For more detailed information about the ECB please visit: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_15_14.pdf

Figure 6. European corn borer moth captured on a wing trap. Photo Credit: Suranga Basnagala.

European Corn Borer Map:May 22 – 28, 2023

Figure 7. Average European corn borer (IA) moths captured from May 22^nd to May 28^th.. The bold number on the left indicates the average number of moths captured. The second number on the right indicates the number of traps monitored in each county. No ECB-NY were reported over the previous week.