Homoptera (Heteroptera): Adelgidae
Identification
• Cooley spruce gall adelgid appears as conelike galls 1 to 11/2" long
on the ends of spruce twigs. (a)
• Eastern spruce gall adelgid appears as conelike growths about 1"
long at the base of spruce twigs.
• Both galls can be distinguished from cones by the spruce needles
sticking out of the galls. (b)
• Cooley spruce gall adelgid also occurs as 1/8" long, white, fuzzy
insects on Douglas fir needles. (c)
Damage
• Heavy infestation can cause dieback of spruces and occasionally death
of the tree.
Management
• Spray spruces with chemical insecticides in early spring before the
gall forms or late fall when adults are preparing for winter.
Other Information
• Cooley spruce gall adelgid does not have to alternate between its
spruce and Douglas fir hosts.
• The galls are green in the spring. They then turn brown later in
the summer and split open, allowing the adult adelgids to escape.