Lep Monitoring Network – Fall Armyworm Update and Last Week of Corn Earworm Reports # 19

This past week rounded out our 19^th week of monitoring for Ohio pests at the Lep Network. This week has been our third week reporting on the fall armyworm (FAW) with average numbers for this pest continuing to rise; as well as our last week reporting on corn earworm (CEW) populations across the Ohio counties as this pest as all-but died off for this season. This past week, Van Wert County saw a variety of mixed moths in their FAW traps and identified these imposters as a combination of green clover worm adults and wainscot moths (Figure1). Some traps were dominated by wainscot moths with some traps reaching up to 82 of these imposters in one trap! We plan to continue updates on this infestation in Van Wert County and other potential, interesting pest phenomena. While CEW numbers have slowed to practically nothing, FAW numbers keep rising in a select number of counties. If your county has seen a surplus of fall armyworm pests this past week, we recommend continuing to scout for egg masses and larva for this damaging pest.

Figure 1. Mix of fall armyworm, green clover worm adults and wainscot moths in a green bucket trap. Photo Credit: Curtis Young, OSU Extension, Van Wet County.

Fall Armyworm 

This is our 3^rd week monitoring for FAW pests in Ohio and these moths are wasting no time racking up their trap counts! The statewide average for FAW this past week has decreased from 37.7 during the week ending on August 18^th to 27.1 for the week ending August 25^th. Counties with the highest averages are Wayne (98.5), Van Wert (71.2) and Henry (35.0) (Figure 2). This week, several counties are seeing a spike in FAW pests with Van Wert County seeing a whopping 237 moths in one trap.

The fall armyworm is a sporadic corn, sorghum, small grain, pasture grass, and forage crop pest, not to be confused with its other armyworm counterparts: true, beet, and yellowstriped. This armyworm is a tropical pest that overwinters in warm soil in the southern US. Since this is a sporadic pest, infestations are infrequent, yet can be damaging when they occur. The last FAW outbreak seen in Ohio was recorded in 2021 where damage from this moth has substantial effects on alfalfa, clover, turfgrass, fall cover crops and small grain fields. Since we are only at the beginning of the season for FAW, scouting should be focused primarily on egg masses and larva (Figure 3). Counties with high reports that should begin scouting are: Henry, Lucas, Van Wert, and Wayne.

For more information on the fall armyworm, visit one of our previous articles: https://ohioline.osu.edu/factsheet/ent-0093

Fall armyworm moth map

Week 3

August 19^th to August 25^th, 2024

Figure 2. Average fall armyworm (FAW) moths captured from August 19^th to August 25^th. 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 3. Newly hatched fall armyworm (FAW) larva and remanence of the egg mass. Photo Credit: Curtis Young

Last week for Corn Earworm

This is our 12^th and final week of monitoring for CEW pests in Ohio. Overall, numbers continue to remain low for CEW. The only counties with any reports this past week were Clinton (1.0), Morgan (1.0), and Putnam (0.3) (Figure 4). To learn more about the corn earworm, check out our previous work: https://agcrops.osu.edu/newsletter/corn-newsletter/2019-27/corn-earworm-field-corn-watch-molds

Corn earworm moth map

Week 12

August 19^th to August 25^th, 2024

Figure 4. Average corn earworm (CEW) moths captured from August 19^th to August 25^th. 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.