Largest infestation of the tussock moth caterpillar in 20 years, Mountain View experts say

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The tussock moth caterpillar is no stranger to these parks. But experts in Mountain View said this is the largest infestation they've seen in nearly 20 years.

A warm February meant an early hatch, before the city's first application of insecticide could take effect.

Dora Andrade of Mountain View said: "Oh I think they're gross. When we first came out and saw them they were just like all over; all over the garbage cans and the trees. And you walk and they fall in your hair."

They like trees, especially oak. Eagle, Pioneer and Rengstorff parks in Mountain View have been especially hard hit. And while experts say the caterpillars don't pose a health risk, the hair on their bodies can irritate the skin and cause a rash.

And when the caterpillars take over the slides and swings, the kids steer clear.

"Normally this has got a bunch of kids around it at this time," Raymond Andrade said. "Now you just got the soccer guys which they're not affected by it cause it's in the open area. But when the kids come over here they run right into them."

Mountain View is taking steps to address the problem now, hosing down the trees and also spraying some parks with an insecticide derived from the chrysanthemum flower. Experts say the caterpillars should hang out in their current form until about mid-spring. And then there should expect a bumper crop of moths. 

Still for those looking to play or picnic, they can be a nuisance.

"They're huge," Andrade said. "They're pretty big. Hopefully they'll get rid of them soon."