Voracious leaf-eating moth found in Mendocino County

Two European gypsy moths, Lymantria dispar, were caught in the Anderson Valley area this month in agriculture department traps, according to the California Department of Food and Agriculture.

With a Latin name that translates into “destroyer,” the European gypsy moth’s first known appearance in Mendocino County is not to be taken lightly.

Adult moths also have been recently captured in pheromone emitting traps in Marin, Alameda and Los Angeles counties, said department spokesman Jay Van Rein. Moth eggs have been found in Sonoma County at least once, in 2006. They were attached to a boat belonging to people who had recently moved to the area, according to news reports.

As caterpillars, the moths are voracious leaf consumers that can defoliate trees and shrubs. A single gypsy moth caterpillar can eat up to 1 square foot of leaves per day, according to the state agriculture department. If they persist, affected trees can eventually starve to death or become susceptible to other diseases that finish them off.

“The East Coast and South lose thousands of acres of hardwood forests annually” to the gypsy moth, said Mendocino County Agricultural Commissioner Chuck Morse.

They have been known to feed on hundreds of different plants. While they primarily like hardwoods, they also devour conifers, shrubs and may even threaten agricultural crops, like grapes, said Greg Giusti, a forest advisor with the University of California Extension Service.

“This is a big deal,” he said.

Agricultural officials are hoping the two male moths were the only ones. None have been found since last week, Morse said. They were caught in traps that lure them with the scent of the female gypsy moth.

The bugs typically hitch rides across the country in moving vans and on recreational vehicles, boats, trailer and lawn furniture while they’re still in egg form. Officials at agricultural inspection checkpoints between states stop and check people transporting such items across state lines, Van Rein said. They question people who are moving from infested areas and notify the agricultural officials near their new homes. But they can’t stop everyone and look at every item.

In response to finding the first moth on July 21, Mendocino County agriculture officials set out additional pheromone traps in the 4 square miles surrounding the location. The second moth was found in a trap at the same site at which the first moth was found, officials said. None have been found since. The other good news is the males don’t fly long distances and the females don’t fly at all, unlike its cousin, the Asian gypsy moth.

The agriculture department will continue to monitor traps through the end of September, when the moth’s life cycle will conclude for the year, officials said.

If an infestation occurs, tougher measures could be employed. But the best steps are preventive, Giusti said.

“Hopefully they don’t catch any more and the threat is obliterated,” he said, noting there are plenty of other foreign pests to worry about.

You can reach Staff Writer Glenda Anderson at 707-462-6473 or glenda.anderson@pressdemocrat.com. On Twitter ?@MendoReporter