Viability and cold tolerance of elongate hemlock scale (Hemiptera: Diaspididae)

Sunday, November 13, 2022

10:36 AM – 10:48 AM PT

Location: Vancouver Convention Centre, Meeting Room 111/112

Presenting Author(s)

Julia B. Leone (she/her/hers)

Postdoctoral Researcher
University of Minnesota
Saint Paul, Minnesota

Co-Author(s)

Pheylan A. Anderson

Lab Manager
University of Minnesota
Anoka, Minnesota
Marie Hallinen (she/her/hers)

IPM Coordinator
Environmental Protection Agency, Region 10
Seattle, Washington
AA

Angie Ambourn

Minnesota Department of Agriculture
Maplewood, Minnesota
BA

Brian Aukema

Professor
University of Minnesota
Saint Paul, Minnesota
TP

Toby R. Petrice

Research Entomologist
USDA-Forest Service
Lansing, Michigan
RJ

Robert Jetton

North Carolina State University
Cary, North Carolina
RV

Robert Venette

USDA-Forest Service
Saint Paul, Minnesota

The elongate hemlock scale, Fiorinia externa Ferris, is an invasive armored scale from East Asia that threatens some native conifers in the United States and Canada. The insect was first discovered in New York in 1908 and subsequently spread south to Georgia, north to Maine, and west to Michigan. Its primary host in this region is eastern hemlock, Tsuga canadensis. However, it also infests other Tsuga spp. and other cedars, spruce, junipers, and firs, especially Fraser fir, Abies fraseri, a tree commonly produced for Christmas trees and other holiday greenery. Heavy infestations can lead to yellowing, needle drop, and eventual branch dieback. In recent years, F. externa has been intercepted on imported holiday greenery from the southeastern United States by agricultural departments in the midwestern United States, including Wisconsin, Minnesota, and South Dakota. In order to better understand the risk this insect may pose to local Christmas tree industries and to the environment in the Midwest, we present research on F. externa cold tolerance, viability, and climatic acclimation. We adapted Biochemical Viability Test methods (BVT) for F. externa and measured supercooling points. Supercooling points were determined by cooling excised scales attached to copper-constantan thermocouples in a silicon chiller bath. Changes in supercooling points provide evidence for seasonal cold acclimation in F. externa.