Young larvae of aspen leaf beetle feed on the undersides of aspen leaves. The arrow points to the cluster of eggs that produced the larvae. / Photo Credit: Wisconsin DNR

By Linda Williams, Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov, 920-360-0665.

Aspen leaf beetles have recently been spotted defoliating young quaking aspen trees in Vilas and Oneida counties.

Both adults and larvae will feed on aspen leaves. The defoliation level detected was light to moderate.

Older aspen leaf beetle larvae feed singly or in small groups on the underside of aspen leaves. / Photo Credit: Wisconsin DNR

Aspen leaf beetles are native to North America. Young larvae feed as a group on the underside of leaves. As they get larger, they will disperse and feed singly or in very small groups.

Adults live for more than one year. Reports of this beetle seem to be more common in Canada than in the United States. The beetles are interesting because both adults and larvae exude a liquid from glands along their back that smells slightly like nail polish remover.

Native predators and parasites help to control populations that get too large. Young aspen will typically recover from this defoliation, so management work is generally not undertaken for this insect.

Aspen leaf beetle adults also feed on aspen leaves. / Photo Credit: Wisconsin DNR