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Agronomic Crops Network

Ohio State University Extension


Lep Monitoring Network – Corn Earworm Update # 9

Here at the Lep Monitoring Network, we have just concluded our ninth week of monitoring for Ohio pests and are happy to report on our second week of monitoring for corn earworm! While scouting numbers were relatively low this past week, Clinton and Muskingum Counties tied for the highest average of CEW moths from June 10th to June 16th.

Watch for Western Bean Cutworm

For this coming week, and subsequently our next newsletter (#10), we will begin reports for western bean cutworm (WBC) moths, compiling data from 24 counties across Ohio. Traps for this pest are being set this week in preparation for next week's newsletter, and we plan to monitor for WBC for a total of 7 weeks. Western bean cutworm is a common pest of dry beans and a sporadic pest of corn in Ohio. Adults are primarily dark brown and black and can be identified by a distinct comma or crescent-shaped mark in the middle of each wing that is seated behind a light brown to tan colored dot. A white stripe can also be seen along the top edge of the forewing (Figure 1). To continue the conversation and learn more about the western bean cutworm, please visit:

Figure 1. Corn earworm caterpillar on leaf. Photo credit: Adam Sisson, Iowa State University,

Corn Earworm

As mentioned above, this is our second week of monitoring for CEW pests in Ohio. While reports of this pest are low as of now, expect CEW numbers to increase as we get further into the season scouting for this damaging corn pest. The statewide average for CEW decreased from 0.89 during the week ending on June 9th to only 0.12 for the week ending June 16th. Counties with the highest averages included Clinton (1.0), Muskingum (1.0) and Morgan (0.5) (Figure 2). As a short reminder from last week’s newsletter -- while scouting numbers are currently low, it is still important to be ready for CEW pests in Ohio and scouting is the best way to stay ahead of any infestations before they happen. As the name implies, corn earworm is a common pest of sweet corn in its larval stage. When looking for a place to lay their eggs, CEW moths are attracted to fields that are in the early green silk stage of development; this is when fields will be most susceptible to damage. Caterpillars vary in color from light to dark but will always have the same characteristic markings (Figure 3). While scouting for the caterpillars of this pest is all but impossible, monitoring for adults (Figure 4) is important to predict larval damage in a field. To monitor for CEW moths, we are using green bucket traps with a lure that attracts adults to the trap. Traps are checked weekly, and an average is reported for each monitoring county. To learn more about corn earworms, check out one of our previous newsletters:

Corn earworm moth map

Week 2

June 10th to June 16th, 2024

Figure 2. Average corn earworm (CEW) moths captured from June 10th to June 16th. 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.

Figure 3. Corn earworm caterpillar on leaf. Photo credit: Joe Culin, Clemson University,

Figure 4. Corn earworm moth. Photo credit: Rebekah D. Wallace, University of Georgia,

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.