Species Insects & ArthropodsCalifornia Root Borer

California Root Borer

Prionus californicus

UncommonInsect & Arthropod
Illustration of California Root Borer (Prionus californicus)

The California Root Borer is a large, robust longhorned beetle with a broad, flattened body, serrated antennae in males, and a rich chestnut-brown coloration. Its larvae are serious root pests of orchard trees, grapes, and hops in the western United States. Adults fly at night in summer and are attracted to lights, sometimes alarming people with their large size.

Habitat
Orchards, vineyards, forests, and oak woodlands
Diet
Larvae: roots of trees and woody shrubs. Adults: do not feed
How common
Uncommon

Best time to see a California Root Borer

The best time to see a California Root Borer is June–July, when about 64% of U.S. sightings happen, based on 4,528 research-grade iNaturalist observations.

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Not certain it is a California Root Borer? What bug is this? walks through what to check first and the lookalikes that catch people out.

Recent California Root Borer sightings near you

Live, research-grade observations from iNaturalist. Allow location to center the map on you.

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