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Lep Monitoring Network Update #12 – High WBC Numbers – Time to Scout!

The Ohio Lep Network is continuing to monitor moth pests across Ohio. As we have begun our 12th week of monitoring, we are continuing population reports for Western bean cutworm (WBC), corn earworm (CEW), and both variations of European corn borer (ECB - IA & NY).

Although black cutworm (BCW) and true armyworm (AMW) monitoring for this season have both come to a close, it should be noted that Van Wert County, which had been seeing an increase in population numbers for several weeks after the typical peak, is continuing to see a climb in BCW numbers while AMW numbers are beginning to decline. This week Van Wert County reported an average of 11.2 BCW compared to the 7.2 average of last week, and an average of 4.6 AMW – a slight decrease compared to the 6.6 average reported last week.

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

Watching the Western Bean Cutworm
This is our fifth week reporting on adult Western bean cutworm (WBC) populations across Ohio. In total, 24 counties have been monitoring for WBC, using 78 total traps. The highest average reports for WBC come from Lucas County, with an average of 100 moths in 1 trap. Sandusky and Defiance counties also reported high averages of moths this past week (Figure 1).

As mentioned in our most recent newsletter (#11), counties with an average of 7 or more WBC should continue scouting for WBC egg masses (Figure 2). Several counties across northern Ohio moving from west to east are seeing averages topping 7, so be sure to check your county average! The stark increase we have been seeing these past two weeks indicates that we are nearing the peak for WBC. For more information on how to scout for WBC and what to look for, see last week's newsletter: https://agcrops.osu.edu/newsletter/corn-newsletter/2023-23/lep-monitoring-network-update-11-%E2%80%93-time-scout-wbc

Western Bean Cutworm Moth Map
July 17th – 23rd, 2023

Figure 1. Average western bean cutworm moths (WBC) captured from July 17th – July 23rd. 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. Western bean cutworm egg mass found on corn leaves. Pencil included for scale.

Chasing the Corn Earworm
This is our seventh week reporting on corn earworm (CEW) populations across Ohio. In total, 12 counties have been monitoring for CEW, using 21 total traps. The highest average reports for CEW come from Henry County, with an average of 4 moths (Figure 3). For more information on the corn earworm as well as the threats they pose, see our previous newsletter: https://agcrops.osu.edu/newsletter/corn-newsletter/2019-27/corn-earworm-field-corn-watch-molds

Corn Earworm Moth Map
July 17th – 23rd, 2023

Figure 3. Average corn earworm moths (CEW) captured from 17th – July 23rd. 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.

Exploring the European Corn Borer
This is our tenth week reporting on European corn borer (ECB – IA & NY) populations across Ohio. In total, 12 counties have been monitoring for ECB-IA, using 39 traps. The only county to report ECB presence this past week was Hardin County with an average of 0.5 moths (Figure 4). No moths were reported across all participating counties for the ECB-NY variant.

For more detailed information about the European Corn Borer visit our previous article at: https://aginsects.osu.edu/sites/aginsects/files/imce/ENT_15_14.pdf

European Corn Borer Moth Map
July 17th – 23rd, 2023

Figure 4. Average European corn borer moths (ECB) IA variant captured from July 17th – July 23rd. 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 NY variant had 0 moths recorded across all participating counties.

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.