D3130: Cold tolerance of elongate hemlock scale (Hemiptera: Diaspididae), an invasive insect associated with the holiday greenery pathway

Fiorinia externa Ferris, the elongate hemlock scale, is an armored scale originating from East Asia. It was discovered in New York in 1908 and has spread throughout much the Eastern USA, currently ranging from Georgia to Maine and west to Michigan. In this region its primary host is eastern hemlock, but it is known to infest many conifer species, including spruces and firs. Fraser fir is commonly used for Christmas trees and decorations such as wreaths. Heavy infestations of F. externa can lead to yellowing, needle drop, and eventual branch dieback. In recent years, F. externa has been intercepted in Midwestern states such as Wisconsin, Minnesota and South Dakota on holiday decorations including wreaths and trees imported from the Southeastern USA in late autumn and early winter. The cold tolerance of insects from North Carolina was measured with contact thermocouple thermometry. To better evaluate the risk this insect may pose to local Christmas tree industries and to the environment in the Midwest, we present our ongoing research into F. externa cold tolerance and seasonal acclimation.