TACOMA, Wash. — U.S. Customs and Border Protection discovered a serious infestation of Asian Gypsy Moth egg masses on a cargo ship at the Port of Tacoma on January 23.
The masses were discovered on an empty bulk grain carrier that had visited a port in East Asia, a region known as a potential Asian Gypsy Moth risk area.
Asian Gypsy Moths are a serious threat to U.S. forests and urban landscapes. The moths are known to attack more than 500 species of trees and other plants.
Following the discovery of the egg masses, the ship was ordered out to international waters for cleaning. During cleaning 275 egg masses were discovered and removed from the vessel. The ship was then re-inspected by U.S. Customs and Border Patrol and released to load cargo in Tacoma.
As with most moths, Asian Gypsy Moth adults are attracted to lights, including those used in seaports at night. The adult females swarm to the lights on loading ships and lay their eggs on the exposed surfaces. Each egg mass, though only a few inches long, can contain up to 1000 eggs.
If the moths became established in the United States, they have the potential to spread rapidly, since adult females can fly up to 25 miles.