Hypericum kalmianum (St. Johnswort) Confirmed as a New Host of the Crapemyrtle Bark Scale in Virginia, U.S.A.

Abstract

Crapemyrtle bark scale (CMBS), Acanthococcus (=Eriococcus) lagerstroemiae (Kuwana) (Hemiptera: Eriococcidae), is an important insect pest of crapemyrtle, Lagerstroemia spp. (Lythraceae), one of the most popular flowering shrubs in the United States. Since first detected in Texas in 2004, this pest has spread to 12 states (Gu et al. 2014), causing economic losses to growers of nursery crops and aesthetic injury that require management inputs to nursery and landscape trees. First observation and collection of A. lagerstroemiae in Virginia occurred in 2014 at a residence in Chesapeake, VA. The number of confirmed infestations had increased to 220 sites in six localities in coastal Virginia by 2018 (PBS, unpublished data). Initially thought to be monophagous, A. lagerstroemiae not only attacks crapemyrtle but also other plant species in a number of different families. In China, Japan and Korea, this pest was reported on 13 other plants of ecological and economic importance (Wang et al. 2016). Despite being present in the United States for more than 14 years,A. lagerstroemiae had only been observed feeding on crapemyrtle (Gu et al. 2016) until reported from American beautyberry (Callicarpa americana L.; Lamiaceae) in 2015 in Texas and Tennessee (Wang et al. 2016, F. Hale, personal communication). Identifying potential alternate hosts and confirming the species identification of suspect scale insects is critically important for developing an integrated pest management program for this newly invasive pest. Here, we report a new host for A. lagerstroemiae in the United States. Acanthococcus lagerstroemiae was first observed by PBS in a demonstration garden plot at the Hampton Roads Agricultural Research and Extension Center (HRAREC), a unit of Virginia Tech and the Virginia Agricultural Experiment Station located in Virginia Beach, VA (36°53′32′′N, 76°10′48′′W) in 2017 on dwarf crapemyrtles (Lagerstroemia ‘GAMAD IV’ (PP# 17219), Ruby DazzleTM) purchased from a commercial nursery in Smithfield, VA (36°56′58′′N, 76°35′48′′W) in 2009. The crapemyrtles died over the winter of 2017–2018. Mortality was at-