Douglas-fir tussock moth

Orgyia pseudotsugata · Order: Lepidoptera · Family: Erebidae

Damages trees, gardens or crops. The larvae damage Douglas fir, grand fir, white fir and other conifers.

Douglas-fir tussock moth — Photo: Ken-ichi Ueda, CC BY

Caterpillars grow to 20 to 26 mm, feed on the needles of Douglas fir and related firs, and can cause defoliation during outbreaks that last several years.

Source: Wikipedia

How to recognize it

Adult males are grayish brown with mottled light and dark patterns.

Source: Wikipedia

Size

Males have a wingspread of 25 to 34 mm. Caterpillars measure 20 to 26 mm long.

Source: Wikipedia

How to get rid of it

Monitoring with pheromone traps helps detect outbreaks early. Silvicultural practices or aerial sprays of carbaryl are used to manage infestations.

Source: Wikipedia

Life cycle

Larvae spin cocoons and pupate in July or August, with adults emerging later in the season.

Source: Wikipedia

Where it is found in the US

Recorded in 13 of 51 states and DC. Most records: Colorado, New Mexico, California, Washington, Montana, Idaho, Arizona, Oregon.

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Darker = more records. Counts are museum and citizen-science records, not population size.

Source: GBIF

Status: native in North America; native in United States; native in Canada. Source: iNaturalist

Months it is reported in the US

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Source: GBIF

More photos

Douglas-fir tussock moth photo 3 — Photo: Aaron Allen, CC BY

Douglas-fir tussock moth photo 4 — Photo: David McComb, CC BY

Douglas-fir tussock moth photo 5 — Photo: Michele Jones, CC BY

Douglas-fir tussock moth photo 6 — Photo: antimatterbee, CC BY

Questions people ask

How can I control a Douglas-fir tussock moth outbreak?

Entomologists use pheromone traps to spot outbreaks early, and managers may apply silvicultural methods or aerial carbaryl sprays to reduce the larvae.

Source: Wikipedia

When are the moths active?

Adults fly from late summer into November, while eggs hatch in May-June and larvae feed through the summer.

Source: Wikipedia