Elongate Hemlock Scale

ODNR recently held a workshop in Spring of 2023 on Hemlock Wooly Adelgid(HWA) and Elongate Hemlock Scale(EHL) at Penitentiary Glenn in Like County. So as a horticulturist or homeowner, what should you do. Inspect your plants and report what you find.

Tom Macy (Forest Health Program Administrator, Division of Forestry, Ohio Department of Natural Resources) has organized a workshop on treatment options for two non-native invasive pests threatening hemlock in Ohio: hemlock Woolly Adelgid (HWA) and Elongate Hemlock Scale (EHS).

Participants at yesterday's Greater Cincinnati BYGLive! Diagnostic Walk-About observed Elongate Hemlock Scale (EHS) on its namesake host. This non-native armored scale has a wide conifer host range beyond hemlocks. It may be found on firs, Douglas-fir, spruces, cedars, and occasionally pines and yews. I first came across EHS in southwest Ohio in 2010 infesting a Cilician fir in a high-profile landscape.

I received an e-mail message this past Wednesday from Tom Macy (ODNR) concerning efforts to discover locations of the non-native elongate hemlock scale in Ohio and other states. His message included two attached images taken by Bill Laubscher (Pennsylvania Bureau of Forestry) on November 20 that showed both the scale as well as odd looking blackened accretions on hemlock needles.

The non-native Elongate Hemlock Scale (Fiorinia externa), which is sometimes called "Fiornia scale," occurs on the underside of needles and on cones.  It may infest its namesake host as well as on other conifers including firs, Douglas-fir, spruces, cedars, pines, and yews.  The scale was accidently introduced to the U.S. from Japan and was first found in New York, NY, in 1908.  Currently, it's found in much of the native range for eastern hemlock (Tsuga canadensis) and Carolina hemlock (T. caroliniana).  Where it overlaps with the non-native Hemlock Woolly...