Elongate Hemlock Scale, Fiorinia externa

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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).

Known populations in Maine:

Kennebunkport, planted hemlocks.

Kennebunk, planted hemlocks planted 2000 or earlier, native hemlock and fir adjacent to the plantings.

Where to look: Planted hemlock, fir and spruce. Planted and natural hemlock in areas affected by hemlock woolly adelgid.

Field Characteristics (See Photos Below): Yellowed 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 dark paper.

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

Heavy scale population on hemlock (note floss in upper right quadrant):

Heavy population of elongate hemlock scale on hemlock. Photo: MFS

Adult males (only winged form):

Note: The males pictured below are trapped in petroleum jelly.

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

Crawlers (~0.1 to 0.2 mm):

Note: The crawlers pictured below are trapped in petroleum jelly.

Crawlers caught on sticky trap, Sept. 10, 2009, Kennebunkport, ME. Photo: ME Department of Agriculture.

Needle discoloration:

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. Photo: Maine Forest Service

Report Suspected EHS

Modified: September 25, 2009