Caterpillar Army Invades Disgusted Bay Area Town

Much to the disgust of residents in this San Francisco suburb, an invasion of caterpillars is thriving on the crisp, spring weather that has come to the area.

“It’s been so gross!” Dola Miller said Monday. “Our neighborhood is straight out of a Stephen King novel. We are talking about millions of caterpillars.” Jackie Gilliam, another resident, said mealtime is difficult for her.

“When you’re trying to eat breakfast while these things are crawling up the screen, it’s not real appetizing,” she said.

Dropping Out of Trees

Residents first noticed the tent-like webs of the caterpillars forming in oak trees early this month. Then last week, thousands of the fuzzy brown critters began to drop and crawl out of the trees.

John Gouvaia, senior biologist for the Alameda County Agricultural Commissioner’s office, said the area’s spring climate was very agreeable to the caterpillars.

“They like a mild spring, as opposed to the dry heat of summer or the cold months of the winter,” he said.

Dubliners spent most of the Easter weekend spraying their backyards with a pesticide and then sweeping up the dead creatures. They reported caterpillars covered sidewalks and decks, wriggled their way up walls and dangled and dropped from roofs and trees.

Too Late to Spray

The city’s Department of Public Works planned to spray an oak tree where many of the caterpillars are born. But Gilliam and Miller said it will be too late. They said the city should have sprayed when residents first reported the caterpillar tents.

Gouvaia said the caterpillars, which hatch from eggs on oak trees, are native to Alameda County and surrounding areas and that they have been part of the natural pattern for thousands of years.

The caterpillars go through cycles, and they are hatched in very large numbers every seven to 10 years. Gouvaia said there was a large population last year, too, and there probably will be a fairly substantial one next year.

“The big problem is that people can’t interface with larvae hanging off their houses and crawling in their backyards.”

Commercial sprays are available for killing the critters but there is no way to get rid of them completely. Gouvaia said natural predators, such as birds and wasps, will cut down the population in a year or so.