Distribution, life cycle, and natural enemies of crapemyrtle bark scale, Acanthococcus lagerstroemia (Kuwana), in Tennessee

Crapemyrtle bark scale (CMBS), Acanthococcus (= Eriococcus) lagerstroemiae (Kuwana), an invasive pest from Asia, is a threat to the ornamental nursery industry, homeowners and landscapers in the U.S. Although feeding is not fatal to many crape myrtles, its effects on aesthetics will affect the sale (valued at >$46 million annually) and use of crape myrtle in landscapes. This pest species has been found in numerous states, including Tennessee. Little is known about its state-wide distribution, life cycle, biology, natural enemies, and impact on crape myrtles. The purpose of this two-year study is to gain additional knowledge to mitigate CMBS before it becomes an economic barrier for crape myrtle production and growth. This pest was first found in Shelby County in Tennessee in late 2013; as of August 2020, CMBS had been documented in 13 counties (eight in western TN, four in middle TN, and only one in eastern TN). It has now been found in three major metropolitan areas (Knoxville, Memphis and Nashville), and extensive damage is apparent in these areas. Biweekly sampling of CMBS suggests that the life cycle of CMBS in Tennessee encompasses eggs, four nymphal instars, and adult females (sessile) and winged males, with two or three overlapping generations per year. Overwintering populations of last-stage instar females, adult females, and pre-pupal/pupal males were found in mid-February. Populations of several species of lady beetles were found to reduce CMBS densities at some locations. This poster will describe the results of this study highlighting distribution, seasonality, and life cycle.