Elongate Hemlock Scale, Fiorinia externa

Alternate name: Fiorinia scale, Abbreviated Name: EHS

Hosts: Hemlock, fir = primary hosts. Spruce is also a common host. Secondary coniferous hosts only usually infested in the presence of heavy scale populations on primary hosts. Pines not affected.

Distribution in US: South to Georgia and South Carolina, west to Ohio, Michigan and Minnesota and, north to southern New York and New England (including southern NH and ME).

Known populations in Maine (year detected in parentheses): map

Forest Stands:

York County: Kittery (2010)

Planted Trees (hemlock unless otherwise noted):

York County: Berwick (2011, planted fir), Kennebunk (2009, escaped to native fir and hemlock), Kennebunkport (2009), Old Orchard Beach (2010), Wells (2011), York (2011, two sites one on planted hemlock, other on planted fir)

Cumberland County: Cape Elizabeth (2010, escaped to native hemlock and planted fir), Scarborough (2011, on planted fir), Gorham (2011, on planted fir)

Where to look: Planted hemlock, fir and spruce. Planted and natural hemlock in areas affected by hemlock woolly adelgid or near detections of elongate hemlock scale.

Field Characteristics (See Photos Below): Yellow spots on foliage apparent on the upper surfaces of the needles. Foliage of more heavily infested trees will have a dirty appearance from a distance. Crowns may be thin. Female scales are covered by a parallel-sided, yellowish-brown waxy coating. Males, by a white, elongate coating. Crawlers and adult males are tiny, yellow, translucent and soft bodied. Crawlers are present during the warmer months of the year. Presence of crawlers and winged males can be determined by jarring infested foliage over a piece of petroleum jelly coated dark paper.

NOTE: In 2009, 2010 and 2011 detections of elongate hemlock scale have been reported during the last week of August. The insect may be more noticeable at that time due to the length of time it has been feeding over the course of the growing season. It appears to be a good time of year to check your trees for this pest.

Waxy Bloom Apparent from a Distance in Late Summer/Early Fall (pictured below on fir)

Waxy bloom apparent from a distance in late summer/early fall. Photo: MFS

Report Suspected EHS

Photos: More photos can be found at: http://www.invasive.org/browse/subthumb.cfm?sub=304.

Elongate hemlock scale on hemlock needles:

Elongate hemlock scale on hemlock. Photo: MFS

Elongate hemlock scale on hemlock (left) and fir (right):

Elongate hemlock scale (Fiorinia externa) on hemlock (Tsuga canadensis), September 2009. Photo Maine Forest Service Elongate hemlock scale on Fraser fir (September 2011). Photo: MFS

Needle discoloration on hemlock (left) and fir (right):
Note: other pathogens, pests and processes will cause needle yellowing. Look for scale coverings on the needle undersides if yellowing is apparent on the upper surfaces of the needles.

Needle discoloration caused by heavy elongate hemlock scale population on hemlock. Photo: Maine Forest Service

Crawlers (left) and adult males (right, only winged form):
Note: The insects pictured below are trapped in petroleum jelly.

EHS crawlers caught in sticky trap Sept 10, 2009, Kennebunkport, ME. Photo: Maine Dept. of Agriculture Male EHS caught in sticky trap Sept 10, 2009, Kennebunkport, ME. Photo: Maine Dept. of Agriculture

Crawlers (~0.1 to 0.2 mm)

Report Suspected EHS

Modified: May 26, 2011