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Ohio State University Extension

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LEP Monitoring Network Update #5 – Trap Counts for BCW, AMW, and ECB (IA & NY)

Introduction

The Ohio LEP Network is continuing to monitor moth pests across Ohio counties. For our fifth 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 are decreasing, as expected. This will be our last week reporting for both BCW and AMW this season, but the presence of the larval stages is likely in fields now; so be sure to be scouting your fields as necessary. 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/

Breakdown of Black Cutworms

Up until last week, BCW adults, have been our most prevalent pest reported across Ohio. Counties that had high trap numbers should be scouting for larvae in the field (Figure 1); with particular attention to fields that may have attracted BCW adults, such as chickweed and purple dead nettle. It is recommended to monitor fields closely until corn reaches its 6th leaf stage. To do this, monitor at least 20 plants in 5 separate locations weekly for cutworm damage (Figure 2). For threshold information and insecticide treatment options, 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 3). Overall, the statewide average of BCW moths decreased from an average of 2.3 moths last week to an average of 0.9 moths this week, as expected as the season continues. The county that had the most moths caught in just one trap was Muskingum County, with 6 moths in one trap.

Figure 1. Segmented Black cutworm larva (BCW) featuring white underbelly. Photo Credit: Adam Sisson (bugwood.org).

 

Figure 2. Damage to a corn plant, caused by the adjacent ECB larva. Photo credits: W.M. Hantsbarger (bugwood.org).

Black Cutworm Moth Map

May 29 – June 4, 2023

Figure 3. Average black cutworm moths captured from May 29th to June 4th. 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.

Tackling the True Armyworm

We have entered our fifth and final week of monitoring for true armyworm (AMW) moths. With this being the last week of monitoring for AMW, counties with previously high numbers of AMW should continue monitoring fields for possible larvae (Figure 4). For more information on AMW, please reference this previous newsletter: https://agcrops.osu.edu/newsletter/corn-newsletter/2020-18/true-armyworm-infestations

From May 29th to June 4th, 11 counties across Ohio were 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 the previous week's average of 1.3 to an average of 0.9 moths this week. This week, the county with the highest number of AMW in a single trap is Hardin, with 5 moths.

Figure 4. Curled up true armyworm larva displaying yellow and light green lines, with black dots in each segment. Photo Credit: Frank Peairs (bugwood.org).

True Armyworm Moth Map

May 29 – June 4, 2023

Figure 5. Average true armyworm moths captured from May 29th to June 4th. 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, numbers are probable to increase for European corn borer moths, as later season moths. These moths deposit eggs on the underside of corn leaves (Figure 6), where the larvae will then hatch and feed on the corn foliage, before entering the stalk, causing damage to the corn stalk. There are various types of ECB, and we monitor for the IA and NY variations. This is our third week of monitoring and no ECB variants have been reported county-wide May 29th – June 4th. Overall, nine counties monitored for ECB over the past week (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. Small, white European corn borer eggs on a corn leaf. Photo Credit: Frank Peairs (bugwood.org). 

European Corn Borer Moth Map

May 29 – June 4, 2023

Figure 7. Average European corn borer moths (ECB) captured from May 29th to June 4th., 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.

Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.