Douglas-Fir Tussock Moth Expected To Invade Yosemite National Park

Yosemite National Park, CA — Visitors to Yosemite National Park should be prepared for increased numbers of Douglas-fir tussock moth caterpillars from July through September.

The tussock moth is a native insect that is found in middle elevation fir forests near the Crane Flat and Chinquapin areas. Every few decades moth populations irrupt and consume the needles of white fir trees. During an irruption, the caterpillars may kill trees over an extensive area.

Yosemite officials are advising visitors of possible human health effects caused by contact with the tussock moth. The hairs on the caterpillars, egg masses and cocoons may cause allergic reactions. Adverse health effects can include skin irritation, rashes, watery eyes, runny nose, coughing and respiratory distress.

Park visitors should avoid exposure to infested areas in addition to wearing broad-brimmed hats and long-sleeved shirts.