Bug FAQOak Timberworm
Arrenodes minutus · Order: Coleoptera · Family: Brentidae
Also called: Oak Timberworm Beetle, Oak Timberworm Weevil
Source: Wikipedia
Adult oak timberworms are 7 to 25 mm long, reddish-brown to black with yellow spots, and show strong sexual dimorphism in mouthparts. They live in eastern North America, emerge from May to August, and their life cycle lasts two to four years, with larvae tunneling through the tree’s xylem. The beetles are serious economic pests of oaks and other hardwoods, damaging lumber and making it unfit for special uses.
Source: Wikipedia
How to recognize it
Adults are reddish-brown to brownish-black with yellow spots on the wing covers.
Source: Wikipedia
Size
Adults measure between 7 and 25 mm in length and have a shiny, elongate shape.
Source: Wikipedia
Is it a pest in the house?
Heavily infested wood is often unsuitable for flooring, barrel making, or other special uses.
Source: Wikipedia
How to get rid of it
Proper forest sanitation and prompt removal of felled trees help prevent infestations. Treating logs or processed wood with fumigation, steaming, kiln drying, or appropriate pesticides can control the pest.
Source: Wikipedia
Where it lives
They are pests of hardwood trees in North America and are often found under loose bark near tree wounds.
Source: Wikipedia
Life cycle
The life cycle takes two to four years; after hatching, larvae bore directly into the xylem and tunnel across the trunk.
Source: Wikipedia
When you see it
Adults usually emerge in May and remain active until August.
Source: Wikipedia
Where it is found in the US
Recorded in 39 of 51 states and DC. Most records: Virginia, Maryland, North Carolina, Massachusetts, Pennsylvania, New York, Tennessee, Illinois.
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
How long does the oak timberworm live?
Its life cycle lasts two to four years from egg to adult.
Source: Wikipedia
When are adult oak timberworms active?
Adults emerge in May and are active through August.
Source: Wikipedia
What damage do oak timberworms cause?
The larvae tunnel through the tree’s wood, creating galleries that weaken lumber and make it unsuitable for flooring or barrel making.
Source: Wikipedia
How can I prevent oak timberworm infestations?
Remove and properly dispose of felled or wounded trees and treat harvested wood with fumigation, steaming, kiln drying, or approved pesticides.
Source: Wikipedia
Same family (Brentidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Arrenodes_minutus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.