joe hu/town crier A hairy weevil sits atop a yellow starthistle. The hairy weevil, a native of Greece, has been introduced to open space land to combat the spread of the invasive yellow starthistle.

Amid an ongoing debate about pesticide use in weed abatement, the town of Los Altos Hills has discussed various solutions, such as mowing. The Los Altos-based Midpeninsula Regional Open Space District will employ an experimental alternative - fighting non-native weeds with a non-native bug.

The district released 6,500 Eustenopus villosus, hairy weevils, in the Skyline and Foothill-area open space preserves last week to try to to control the spread of the yellow starthistle, a non-native invasive weed. Introduced to California in the 19th century, the starthistle forces out native plants and is an aggressive roadside weed. The hairy weevil is one of several insect species researched by the U.S. Department of Agriculture for use as biocontrol agents.

“Introduction of the weevil is an effort to recreate the natural system of ecological checks and balances that prevent this non-native, invasive plant from eliminating desirable native plants and habitats in the open space preserves,” said Lisa Infante, district’s resource specialist.

Originally from Greece, the hairy weevil is 0.24 to 0.32 of an inch long, has a distinctive long snout with antennae and an overall brown-gray striped color, Long hairs, which cover much of its body, give the weevil a hairy or fuzzy appearance. Both the adult and immature hairy weevils feed on the thistles.

The district first released hairy weevils in 1997 and conducted additional releases in 2004 and 2005. Initial monitoring revealed that 40 percent to 90 percent of yellow starthistle seedheads were damaged by weevil activity. The district will also implement other methods to control and eradicate the yellow starthistle, including mowing, prescribed burning, cutting, pulling and select herbicide applications.