Fiorinia externa

Fir with damage from and heavy infestation of elongate hemlock scale.  Photo: Maine Forest Service

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Alternate name: Fiorinia scale, Abbreviated Name: EHS

Hosts: Hemlock and fir are primary hosts. Spruce is also a common host. Several other conifers are secondary hosts, although these are usually infested only in the presence of heavy scale populations on primary hosts. Pines are 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: map (PDF | 2.64 MB)

Infestations of elongate hemlock scale on planted trees have been found from Kittery to Mount Desert. To date, forest infestations in the absence of planted trees have only been found in Kittery and Frye Island. It is very probable that elongate hemlock scale is established in Maine's forests outside of these areas.

Towns with known infestations:

Cumberland: Brunswick, Cape Elizabeth, Casco, Falmouth, Freeport, Frye Island, Gorham, Portland, Scarborough, Yarmouth

Hancock:  Sedgwick, Mount Desert

Sagadahoc: Topsham

York: Berwick, Kennebunk, Kennebunkport, Kittery, Old Orchard Beach, Saco, Wells, York

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: Detections of elongate hemlock scale have often 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 Buildup 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, middle (adelgid circled)) and fir (right):

Elongate hemlock scale (Fiorinia externa) on hemlock (Tsuga canadensis), September 2009. Photo Maine Forest Service Hemlock woolly adelgid and elongate hemlock scale on hemlock from Sedgewick, ME.  Photo: MFS 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 Needle discoloration caused by heavy elongate hemlock scale population on fir.  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