Lep Monitoring Network – Western Bean Cutworm numbers continue to rise # 13

This is our 13^th week of monitoring moth pests in Ohio. Between July 14^th and July 20^th, we continued to monitor Corn Earworm (CEW) and Western Bean Cutworm (WBC). Over the past week, the state of Ohio experienced moderate rainfall and average temperatures (78.0 °F). The statewide averages for WBC and CEW remained increased from the previous weeks. Please read below for more details.

Western Bean Cutworm

This week twenty counties monitored WBC (Figure 2) with a total of 54 traps. Sixteen counties trapped WBC this week, which is a decrease from the previous week. However, the average moths per county continue to increase to an average of 13.2 moths. This number is up from last weeks average of 5.4. Counties with the highest averages included Sandusky (139.0), Lucas (13.0), Defiance (21.9), Fulton (11.3), Henry (12.0), Wood (22.7), Putnam (10.6), and Wayne (16.5) (Figure 2). The numbers for WBC are expected to remain high, so counties with an average greater than 7.0 moths should consider inspecting their fields.

How to scout for WBC egg masses

A field of corn that is in the process of forming tassels is an ideal place to start looking for WBC eggs. Examine 20 plants in 5 different locations (100 plants total). Typically, eggs can be found on the underside of upright leaves near the tassel or on the upper side of leaves near the leaf collar. Newly laid eggs are usually a whitish color, and the older eggs can be dark purple (Figure 1). Treatment options should be considered if 5% of plants have egg masses. For optimal results, treatment should be applied when the majority of the eggs found are purple (indicating they are close to hatching).

To view a more detailed video on scouting – click here: https://youtu.be/qGjpwtfkObM?si=CFPzX1rlqt6jzyJw

For more information on how to scout WBC please visit: Western Bean Cutworm | Ohioline

Western Bean Cutworm Moth Map
Week #7
July 14^th to July 20^th, 2025

Corn Earworm

This week we monitored 36 traps in 16 counties across Ohio for CEW moths (Figure 3). The statewide averages of CEW increased across the state with an average of 1.9 moths per county (Figure 4). Putnam County had the highest moth average, which was 19.2. Overall, the statewide averages of CEW have remained low since the beginning of June.

More information on CEW can be found here:

Corn Earworm in Field Corn; Watch for Molds | Agronomic Crops Network

Corn Earworm Moth Map
Week #7
July 14^th to July 20^th, 2025