Reports of armyworm activity have slowed since last week, but the potential for late-season infestations and crop damage remains high. Second-generation true armyworm larvae began appearing in crops and lawns. This is primarily in the southern and western areas of the state, around July 18. The week of July 18-24 brought many armyworm sightings. Most of these involved armyworms migrating through residential yards to nearby crop fields. As of July 31, reports of locally heavy larval populations have been received from Barron, Burnett, Chippewa, Clark, Columbia, Crawford, Dane, Dunn, Eau Claire, Green Lake, Iowa, Jackson, Jefferson, Monroe, Taylor, and Washburn counties.
The timing of the infestations is typical for second-generation armyworms. It also corresponds with large moth flights tracked by DATCP in late June and early July. Additional heavy flights this month (850 moths at Lake Mills in Jefferson County July 4-17) signal a potential for more larvae and feeding to extend well into August. Continued scouting of corn, small grains, and other susceptible crops for armyworms is advised to detect and prevent developing problems.
