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Lep Monitoring Network Update #9 – Trap Counts for CEW, WBCW, and ECB (IA & NY)

Introduction
The Ohio Lep Network is continuing to monitor moth pests across Ohio. As we have begun our nineth week of reporting, we will continue population reports on corn earworm (CEW), Western bean cutworm (WBCW), and both variations of European corn borer (ECB - IA & NY).

While monitoring for black cutworm (BCW) and true armyworm (AMW) have both ended for this season, it should be noted that Van Wert County is seeing a stark increase in both BCW and AMW populations. Across the county, an average of 11.3 BCW and 3.2 AMW were reported this past week alone.

For more information on these pests and many more, check out our website: https://aginsects.osu.edu

Capturing the Corn Earworm
This is our third week monitoring the corn earworm (CEW) pest. 9 counties across Ohio monitored for CEW populations using 13 total bucket traps. Overall, 18 moths were reported (Figure 1). Of the 18 moths reported, 15 CEW were reported in Auglaize County alone.

Figure 1. Average corn earworm moths (CEW) captured from June 26th – July 3rd. 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.

Corn earworm is a common pest found across Ohio which can routinely be found feeding in corn, tomato, and certain legume fields. This frequency of this pest particularly in corn fields can lead to feeding damage, molds, and an increased threat to the plant from birds. Corn earworms are drawn to these corn fields in the early green silk stage in an effort to lay their eggs. A majority of the damage imposed by CEW will be focused on the tip of the affected ear of corn. For more information on CEW and the threats they pose, check out our previous newsletter: https://agcrops.osu.edu/newsletter/corn-newsletter/2019-27/corn-earworm-field-corn-watch-molds

Exploring the European Corn Borer
This is our seventh week monitoring the European corn borer with only 0.5 IA variants and 0 NY variants being reported from June 26th – July 3rd. In total, 9 counties across Ohio are monitoring for both ECB variants, using 25 total wing traps for both. Figure 2 below shows just data for the IA variant, as NY had 0 reports.

Figure 3. Average European corn borer moths (ECB) captured from June 26th – July 3rd, of the IA variant. 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 ECB-NY variant had a total of 0 moths across all our counties in Ohio.

The European Corn Borer (ECB) is a common corn pest of Ohio that restricts the proper and normal flow of nutrients within an affected corn stalk. The ECB pest will ‘bore’ as its name suggests into a stalk of corn, cutting off the flow of nutrients and exposes the host plant to various problems including stalk breakage, ear drop, and a reduction in corn yield (Figure 3); all of which prove quite troublesome – if not detrimental to that season's crop. ECB is more commonly seen as a later season moth, so we expect to see an influx in population numbers for both ECB variants – IA and NY -- in the coming weeks. To be better informed on European corn borers and the threat they pose, visit: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_15_14.pdf

Figure 4. European corn borer crop damage at larval stage. Photo Credit: Mariusz Sobieski, Bugwood.org

Watching the Western Bean Cutworm
This is our second week reporting on adult Western bean cutworm (WBCW) populations across Ohio. 17 counties across Ohio monitored for CEW populations using 50 total bucket traps. Overall, 6 total moths were reported (Figure 4).

Figure 4.  Average western bean cutworm moths (WBCW) captured from June 26th – July 3rd. 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.

WBCW is a common Ohio pest affecting dry beans and corn. WBCW adults emerge anywhere from late June to early July, so we expect to see a gradual increase of WBCW reports in the next week or so. Adults have distinct markings which make for easy identification. Look for a white line along both edges of the forewing, a light tan colored dot inward of the stripe, behind the dot should be a tan-colored boomerang (or crescent) like mark (Figure 5). For more information regarding the Western bean cutworm, visit our previous article: https://ohioline.osu.edu/factsheet/ENT-40#:~:text=Western%20bean%20cutworm%20(WBCW)%20was,corn%20in%20Iowa%20and%20Minnesota.

Figure 6. Adult western bean cutworm (WBCW) markings on a corn leaf. Photo Credit: Adam Sisson, Iowa State University, Bugwood.org

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.