Phenology of the elongate hemlock scale (Hemiptera: Diaspididae) on Fraser fir Christmas trees in western North Carolina.

Understanding the seasonal phenology of an insect pest in a specific region on a specific host is fundamental to the timing of management actions. The elongate hemlock scale, Fiorinia externa Ferris (Hemiptera: Diaspididae), is an invasive insect from Japan known to infest various conifer hosts in its invasive range in eastern North America. The phenology of the scale has been studied on hemlock (Tsuga spp.) hosts in its native range and portions of its invasive range in the northeastern and mid-Atlantic regions of the United States; similar studies are lacking for the southeastern region. In the Southern Appalachians, this scale poses a significant management and regulatory challenge for Fraser fir (Abies fraseri [Pursh] Poir.,) Christmas tree production. The objective of this study was to examine the seasonal phenology of the scale in the western North Carolina production region. Biweekly samples were collected from Fraser fir at three sites over 2 years and analyzed for abundance of each life stage. We found all life stages present at all locations throughout the year. Large variability in egg abundance was observed across 2 years. There was little variability in the abundance of life stages between sampling locations. Substantially more scale eggs, crawlers, 2nd instar nymphs and adult females were observed on the 2 most recent years' needles as opposed to older needles. These findings can help optimize the timing of management practices to control the elongate hemlock scale more effectively.