Douglas-Fir Tussock Moth Lure

Latin Name:  Orgyia pseudotsugata

Lure: Gray Rubber Septum.

Lure Active Ingredient: Z6-heneicosen-11-one

Field Life: 45 days

Trap to Use: Red Paper or Plastic Delta Trap

Monitoring Strategy: Place traps in areas of higher risk. A loping configuration of 5 traps should be set with the first trap approximately 20 meters into the forest from the road. Traps should be place at least 20 meters apart. Place each trap in a relatively open grown tree or at the edge of a dense thicket. Traps should not be hung in dense foliage or in thickets. Traps should be wired very close to the branch. If necessary, remove any foliage that blocks the ends of the trap. Check to be sure the lure has not fallen out during positioning of the trap. Contact your local forester for more information on forest management practices.

Cultural and Physical Control: Thin to generate a low-hazard stand. Do not use equipment that causes soil compaction or erosion. Lop and scatter slash, pile and burn largest pieces only if fuel load is unsatisfactory. Favor species adapted to drought, such as ponderosa pine in place of Douglas-fir on dry sites, and ponderosa pine, lodgepole pine, Douglas-fir and larch on sites capable of supporting true fir species.

Distribution: Native to western North America.

Hosts: Douglas-fir, white fir and grand fir.

Description: Adult moth: Rusty-colored forewings, gray-brow hind wings, with a 25.4 mm wingspan.

Larvae: Black at first, later becoming gray to brown, ~30-35 mm long, with a black head.

Eggs: White, spherical, laid in an egg mass containing about 300 eggs.

Life Cycle: Eggs hatch following bud break. The caterpillars migrate, moving to the new growth but also often dispersing upwards in the trees. They pupate in brownish spindle-shaped cocoons in the vicinity of the infested trees. The adults emerge from late July through mid-August. The males are strong fliers, but the females have only minute, non-functional wings. Mating occurs in the immediate vicinity of the female pupal case and they then lay their characteristic mass of eggs. There is one generation produced per year.