Cooley Spruce Gall Adelgid
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Hosts
Douglas-fir and spruce.
Distribution
On hosts throughout Idaho and Montana.
Damage
On Douglas-fir, nymphs suck out the juice of current needles which turn yellow and fall off. On spruce, nymphs form galls on the tips of twigs and branches.
Identification
Look for galls on spruce. In late spring, the unopened galls are green with shades of pink or purple. Nymphs may be found inside them. Open galls, found in late August, are brown, dry, and resemble small cones (fig. 105). Look f or oval, black nymphs with a white, waxy fringe or oval, dark brown adults covered with white, woolly wax on current Douglas-fir needles during spring and summer months (fig. 106). See Table 4 for comparison of Cooley spruce gall adelgid damage with that of needle casts and midges.
Similar damages
On Douglas-fir, damage may be similar to that caused by Douglas-fir needle midge, Rhabdocline, Swiss needle cast, or aphids.
References
Anonymous. 1982. For. Insect & disease identification and management. USDA For. Serv.,Northern Region; Idaho Dept. of Lands, Insect and Disease Control; Montana Dept. of State Lands, Division of Forestry. 192 p.
Furniss, R. L., and V. M. Carolin. 1977. Western For. Insects. USDA Forest Serv., Misc. pub. 1339, 654 p., illus.
Field Guide to Diseases and Insect Pests of Idaho and Montana Forests, USDA Forest Service Northern Region, Publication Number R1-89-54
