Fir Coneworm

Appearance

The wingspan is 10–13 mm. The forewings are primarily black and white with a prominent spot.

Adult: forewing blackish-gray with black zigzag AM and PM lines, bordered by white; irregular white discal spot in median area; black blotch present inside AM line at costa; hindwing light brownish-gray with pale fringe

Larva: body light reddish-gray with dark dots and dark brown head

Naming

Dioryctria abietivorella (Grote, 1878)
Pinipestis abietivorella Grote, 1878
Myelois elegantella Hulst, 1892
Pinipestis reniculella Grote, 1880

Distribution

US: Arizona, California, Colorado, Illinois, Indiana, Maine, Maryland, Massachusetts, Minnesota, Montana, Nebraska, New Jersey, New York, Oregon, Pennsylvania, Rhode Island, Tennessee, Washington
Canada: British Columbia, New Brunswick, Ontario, Quebec.

Behavior

Adults are nocturnal and attracted to light. Adults fly from May to August. Larvae present from June to September.

Habitat

Coniferous forests throughout range.

Reproduction

Adult lays eggs under scales of new cones or under bark; larva feeds from June to September, then drops to the ground and weaves a silk cocoon where it overwinters in the last larval instar stage or as a prepupa; pupation occurs the following spring; one generation per year.

Food

Larvae usually feed internally on cones, but may also feed on needles, twigs, and under bark of various conifers: mainly balsam fir in the east, and Douglas fir in the west, plus various species of pine and spruce.

Larvae are economically important pests; they do not cause serious damage to the tree but in severe infestations can destroy an entire seed and cone crop, and can be particularly damaging in seed orchards.