CFAES Give Today
Agronomic Crops Network

Ohio State University Extension

CFAES

Lep Monitoring Network – Spike in Numbers: Fall Armyworm Update # 23

This past week was our 23rd week of monitoring for Ohio pests at the Lep Network and our 7th week reporting on the fall armyworm (FAW). Due to a decrease in FAW numbers across the state, as well as nearing the end of the field season in Ohio, this will be our second to last week reporting on this pest for the 2024 season. While we are closing out reports here at the Lep Network, scouting is still important when making educated agricultural decisions in your county. As mentioned in previous weeks, if FAW reports surpass an average of 7 in your county, we recommend continuing to scout for egg masses and larva. Counties that should continue scouting for FAW are: Henry, Muskingum, Van Wert, Wayne, and Wood.

Fall Armyworm Averages and Scouting

The statewide average for FAW this past week continued to drop from 41.2 for the week ending September 15th to only 17.4 moths for the week ending September 22nd. Counties with the highest averages are Wayne (104.5), Van Wert (30.8) and Henry (8.3) (Figure 1). This past week, Wayne County yet again saw the highest trap count with 193 fall armyworms in one trap.

When scouting for FAW, it is important to look primarily for eggs and larva of this sporadic pest because the larval stage is the most damaging. The adult fall armyworm is a species that does not feed, it only feeds in the larval stage. This time of the year, egg masses will be few and far between, but when scouting, know that nowhere is off limits for these pests (Figure 2). FAW moths will lay these masses on a variety of surfaces, including (but not limited to), plant leaves, fence posts, telephone poles, flags and more. When scouting for FAW, continue to be aware of larval presence as a spike in this activity is to be expected near the end of September. When scouting for fall armyworm larva, be sure to look for the distinct white, inverted “Y” shape on the front of this pesky pest's head.

For more information on the fall armyworm, visit our current factsheet on FAW: https://ohioline.osu.edu/factsheet/ent-0093

Fall armyworm moth map

Week 7

September 16th to September 22nd, 2024

Figure 1. Average fall armyworm (FAW) moths captured from Sept 16th to Sept 22nd. 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 2. Fall armyworm egg mass on the underside of a leaf. Photo credit: David Jones, University of Georgia, 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.