Pest Alert - Japanese Maple Scale

Japanese maple scale, Lopholeucaspis japonica , is active now and much of the summer. It is a small, oystershell-shaped, armored scale believed to have been introduced to the U.S. from Asia. Japanese maple scale is found in several eastern U.S. states, including North Carolina, Tennessee and Virginia. Japanese maple scale has a wide host range that in addition to maples (e.g., Japanese maples, red maples, paperbark maples, and sugar maples) Cornus, Ilex, Magnolia, Malus, Stewartia, Ulmus and others.

Although the lifecycle of this pest has not been fully examined, two generations a year are expected in the mid-southern U.S. First generation crawlers emerge in mid-May, and the second generation in early August. Management efforts are complicated by the extended crawler hatch observed for Japanese maple scales that results in first and second generational overlap. Thus, the most recent sample we received had every stage (egg to adult) present at the same time.

Adult scales and crawlers are very small and most readily observed on bark of dormant deciduous host plants, but can also be found on foliage. The waxy coating on the body of male Japanese maple scales is white and females, eggs, and crawlers are lavender. The most work on this scale has been done at the University of Maryland and their fact sheet on the Japanese maple scale is available on the web at this site.

Steve Frank, Extension Entomologist, NC State University