Cone worms - Dioryctria spp.
Cone moths - Barbara spp.
Cone borers - Eucosma spp.

From: Field Guide to Diseases and Insect Pests of Idaho and Montana Forests, USDA Forest Service Northern Region, Publication Number R1-89-54

Hosts. – Douglas-fir, true firs, and most western pines.

Distribution. – Region wide.

Damage. – Larvae feed within cones on cone scales and seeds. External damage ranges from small, misshapen cones (fig. 139) to cones marked only with an entrance hole surrounded by frass and pitch. Larvae may tunnel throughout cone or may nearly hollow it.

Identification. – Larvae vary in color from dirty white to brown to gray – depending on species. Most are one-fourth to three-fourths inch long when mature (fig. 140). Some species are solitary feeders; in others there may be several larvae per cone. Adults, while not often seen, are small moths with wingspans of three-fourths to 1-1/4 inches. All have brown, gray, or orange-mottled forewings and typically gray hind wings.

Similar damages. – Similar cone damage may be done by western spruce budworm larvae. Depending on instar, it may be difficult to separate the various species when in the larval stage.

Link to Images in Forestry Images

Link to Images in Forestry Images

References.

Furniss, R. L., and V. M. Carolin. 1977.  Western For. Insects. USDA Forest Serv., Misc. pub. 1339, 654 p., illus.

Hedlen, A. F., H. O. Yates III, D. C. Tovar, B. H. Ebel, T. W. Koerber, and E. P. Merkel. 1980. Cone and seed insects of North American conifers. Can. Forest Serv., USDA For. Serv., Sec. de Agric. y Rec. Hid., Mexico. 122 p., illus.

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