Elongate hemlock scale (Fiorinia externa) is an insect pest. It is a native of Japan and was first detected in Nevada in 1984.
F. externa attacks the lower surface of the hemlock needle, where it removes fluids from the mesophyll cells through piercing and sucking mouthparts. Scale populations build slowly on healthy trees, but much more quickly on stressed ones. Feeding by elongate hemlock scale causes foliage to turn yellow and drop prematurely.