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Lep Monitoring Network Update #13 – WBC Numbers Remain High, Continue Scouting!

The Ohio Lep Network is continuing to monitor moth pests across Ohio. We are in our 13th week of monitoring, and we are continuing population reports for Western bean cutworm (WBC), corn earworm (CEW), and both variations of European corn borer (ECB - IA & NY).

While black cutworm (BCW) and true armyworm (AMW) monitoring for this season have both finished in June, this week Van Wert County, which had been seeing an increase in population numbers for several weeks after the typical peak, saw a decline in BCW numbers with an average of 8.4, compared to 11.2 of last week.  Van Wert County also reported an average of 5.9 AMW’s, a slight increase to the average of 4.6 insects from last week.

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

Writing on the Western Bean Cutworm
This is our sixth week reporting on adult Western Bean Cutworm (WBC) populations across Ohio. In total, 20 counties have been monitoring for WBC, using 71 total traps (Figure 1). We caught a total of 527 moths with a statewide average of 7.5 moths. These numbers are a decrease from last week (total of 779 and a statewide average of 10). While we believe we are past the peak, there are still a number of counties reporting high numbers. The highest average reports for WBC again come from Lucas County, with an average of 53 moths in 1 trap. Sandusky, reported the highest number of WBC in a single trap (77), however the county average was only 30.3. In addition to Lucas and Sandusky, five other counties had an average of 7 moths or higher including Defiance, Geauga, Hancock, Wayne, and Wood

As mentioned in our previous newsletters (#11 and #12), counties with an average of 7 or more WBC should continue scouting for WBC egg masses, which often reside on the underside of the leaves.  Several counties across northern Ohio have seen decreasing numbers since last week, but if averages are still above 7 for your county, continue scouting for WBC’s! For more information on how to scout for WBC and what to look for, see our previous newsletter: https://agcrops.osu.edu/newsletter/corn-newsletter/2023-23/lep-monitoring-network-update-11-%E2%80%93-time-scout-wbc

Also keep a lookout for a WBC look-alike named the flame-shouldered dart (FSD) moth. They bear the same boomerang and dot markings, with a white stripe on the outer side of the forewing but are smaller than the WBC. For more information, see our article: https://aginsects.osu.edu/news/western-bean-cutworm-moth-look

Western Bean Cutworm Moth Map
July 24th – 30th, 2023

Figure 1. Average western bean cutworm moths (WBC) captured from July 24th - July 30th. 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.

Collecting the Corn Earworm
This is our eighth week reporting on corn earworm (CEW) populations across Ohio. This week, 10 counties have been monitoring for CEW, using 18 total traps. Overall, very few CEW were observed over the past week. Henry County, which had a high of 4 average CEW’s last week, had a decrease in numbers this week and reported an average of 0.5 CEW. The highest average reports for CEW come from Muskingum County, with an average of 1 moth (Figure 2).

For more information on CEW 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 24th – 30th, 2023

Figure 3. Average corn earworm moths (CEW) captured from July 24th - July 30th. 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.

Eluding the European Corn Borer
This is our eleventh week reporting on European corn borer (ECB – IA & NY) populations across Ohio. This week, 10 counties have been monitoring for ECBs using 35 traps.  No moths were reported across all participating counties for both the ECB-IA and ECB-NY variants (Figure 3).

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 24th – 30th, 2023

Figure 3. Average European corn borer (ECB) moths captured from July 24th -  July 30th. 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.