Bug FAQCalifornia Root Borer
Prionus californicus · Order: Coleoptera · Family: Cerambycidae
Also called: California prionus
Source: Wikipedia
Adults are 2.5 to 5.7 cm long, reddish-brown with smooth shiny wing-cases, while larvae are cream-to-brown and strongly segmented.
Source: Wikipedia
Size
Adults measure 2.5 to 5.7 cm in length.
Source: Wikipedia
Is it a pest in the house?
California root borers are considered orchard pests. The tunneling larvae can kill infested trees.
Source: Wikipedia
Where it lives
They spend most of their life underground feeding on the roots of deciduous trees, shrubs, some conifers, brambles, hops and grape vines.
Source: Wikipedia
What it eats
Their diet consists of roots of most deciduous trees, shrubs, some conifers, brambles, hops and grape vines.
Source: Wikipedia
Life cycle
Adult beetles live for 10 to 20 days.
Source: Wikipedia
Where it comes from
The species is native to the western United States.
Source: Wikipedia
Where it is found in the US
Recorded in 16 of 51 states and DC. Most records: California, Arizona, Oregon, Utah, New Mexico, Idaho, Washington, Colorado.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What damage do California root borers cause?
Their larvae tunnel in roots, which can kill trees and harm orchard crops.
Source: Wikipedia
How long do adult California root borers live?
Adults survive for about 10 to 20 days.
Source: Wikipedia
Where is the California root borer native to?
It is native to the western United States.
Source: Wikipedia
What do the larvae look like?
Larvae are cream to brown in color and have strong body segmentation.
Source: Wikipedia
Same family (Cerambycidae)
House LonghornHylotrupes bajulusCan damage your home
Asian Longhorned BeetleAnoplophora glabripennisDamages trees, gardens or crops
Red Milkweed BeetleTetraopes tetrophthalmus
White-spotted SawyerMonochamus scutellatusCan damage your home
Red Pine Longhorn BeetleStictoleptura rubra
Spotted Longhorn BeetleRutpela maculataDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Prionus_californicus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.