The Ohio Lep Network is continuing to monitor for moth pests across Ohio. We have started our 6th week of monitoring, which concludes the monitoring for black cutworm (BCW) and true armyworm (AMW). We will continue to monitor for European corn borer (ECB) IA and NY, and, in the coming weeks, we will be adding traps for western bean cutworm (WBC) and corn earworm (CEW). For more resources on these pests and many others, check out our website: https://aginsects.osu.edu
A Brush with Black Cutworm
This is our final week reporting on black cutworm (BCW) moth numbers in Ohio. Over the past week, 10 counties monitoring 28 traps reported BCW numbers (Figure 1). Overall, the statewide average of BCW moths averages is decreasing as expected. Moths were only reported in 4 counties, with the highest county average being 2 moths per trap in Muskingum County.
Black cutworms (BCW) are an early-season pest that overwinters in the southern states and migrates Northward as the year moves on. Previously, BCW adults have been our most prevalent pest reported statewide, and counties that had high average insect numbers should be scouting for larvae in the fields (Figure 2). Fields should be given special attention if they had weeds such as chickweed and purple dead nettle, as these attracted BCW moths. When monitoring for BCW, it is important to monitor closely, until corn has reached the 6th leaf stage. BCW can cause both above-ground feeding injuries, and below-ground feeding injuries, tunneling, as well as low stand count. (Figure 3). When monitoring, monitor at least 20 plants in 5 separate locations once a week and look for insect presence. If you are looking for more information on BCW symptoms or management, please visit: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_35_14%20BCW.pdf
Black Cutworm Moth Map
June 5 – June 11, 2023
Figure 1. Average black cutworm moths captured from June 5th to June 11th. 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.
Figure 2. Black cutworm (BCW) larvae in the field. BCW can be identified by their black coloration in addition to a white underbelly. Photo Credit: Roger Schmidt (bugwood.org).
Figure 3. Damage caused by BCW, above-ground damage (left), tunneling (middle), and below-ground damage (right). Photo Credit: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_35_14%20BCW.pdf
Taming the True Armyworm
Similar to BCW, this will be our final week of monitoring for true armyworm (AMW). From May 29th to June 4th, 11 counties across Ohio were monitored for AMW, with 27 total wing traps being set (Figure 4). AMW numbers have continued to decrease with only two counties reporting AMW, both located in the more western part of the state.
True Armyworm Moth Map
June 5 – June 11, 2023
Figure 4. Average true armyworm moths captured from June 5th to June 11th. 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.
AMW is similar to BCW as it is an early-season pest and can be a pest for grasses and vegetable plants. These pests migrate from Southern states each year and lay their eggs in grasses such as forage, weed grasses, winter wheat, barley, and rye cover crops. As AMW moths are continuing to decrease across Ohio, attention should be turned to their larval stages (Figure 5). AMWs hide during the day and feed at night, so scouting for them should occur at dawn, dusk, or on cloudy days. AMW are named for their behavior of marching forward like an army. AMW causes the most damage in no-till fields or any fields that have rye as a cover crop. Pay particular attention to fields that are near wheat fields, and if you find AMW in a corn field, check the percentage of plants damaged out of 20 plants. If more than 10% of plants had damage, recheck plants in a few days. If your average remains high, you may want to look into insecticide application if plants are continuing to show damage. Damage will often be present on the leaf blades (Figure 6). It is important to note that AMWs cannot survive on soybean plants, so monitoring for them on soybeans is not needed. If you are looking for more information on AMW check out our previous newsletter from 2020: https://agcrops.osu.edu/newsletter/corn-newsletter/2020-18/true-armyworm-infestations
Figure 5. True armyworm larva. Photo Credit: Frank Peairs and North Carolina Forest Service (bugwood.org).
Figure 6. Leaf damaged by true armyworm and an armyworm visible on a nearby leaf. Photo Credit: https://agcrops.osu.edu/newsletter/corn-newsletter/2020-18/true-armyworm...
Examining the European Corn Borer
This is our third week of monitoring and no ECB variants have been reported from June 5th – June 11th. Overall, ten counties were monitored for both ECB IA and NY using 34 wing traps (Figure 7).
The European Corn Borer (ECB) is a common corn pest in Ohio that bores into corn stalks; this can increase corn stalk disease, stalk breakage, and ear drop, which may result in reduced corn yield. You can identify ECB moths by their white wings, but their darker-colored body (Figure 8). ECB is a later season moth, and we are expecting to see an increase in ECB numbers as the weeks move on. For more information about ECB please visit: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_15_14.pdf
European Corn Borer Moth Map
June 5 – June 11, 2023
Figure 7. Average European corn borer moths (ECB) captured from June 5th to June 11th, both IA & NY variants. 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.
Figure 8. European corn borer moth captured on a wing trap. Photo Credit: Suranga Basnagala.