Bug FAQMountain Pine Beetle
Dendroctonus ponderosae · Order: Coleoptera · Family: Curculionidae
Source: Wikipedia
It lives in many pine species, develops through egg, larva, pupa and adult stages, and can kill trees during epidemic outbreaks.
Source: Wikipedia
How to recognize it
It has a hard black exoskeleton.
Source: Wikipedia
Size
It measures about 5 mm (¼ in), roughly the size of a grain of rice.
Source: Wikipedia
Is it a pest in the house?
Normally it helps forests by attacking old or weakened trees, but hot, dry summers and mild winters caused an unprecedented epidemic that damages pine forests.
Source: Wikipedia
How to get rid of it
Early detection is critical to prevent a runaway outbreak.
Source: Wikipedia
What it eats
It inhabits and chews the inner bark and phloem of its host pines, releasing pheromones as it feeds.
Source: Wikipedia
Life cycle
Its life cycle includes egg, larva, pupa and adult stages.
Source: Wikipedia
When you see it
Adults emerge for a few days in summer to fly to new trees; all other stages stay under the bark.
Source: Wikipedia
Where it comes from
It is native to western North America, from Mexico up to central British Columbia.
Source: Wikipedia
Where it is found in the US
Recorded in 13 of 51 states and DC. Most records: Colorado, California, Idaho, Utah, South Dakota, Montana, Arizona, Wyoming.
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
Why are mountain pine beetles suddenly a problem?
Unusually hot, dry summers and mild winters from 2004-2007 created conditions for a massive epidemic that harms pine forests.
Source: Wikipedia
What trees do they affect?
They infest several pine species, including ponderosa, lodgepole, whitebark and bristlecone pines.
Source: Wikipedia
Same family (Curculionidae)
Green Immigrant Leaf WeevilPolydrusus formosusDamages trees, gardens or crops
Black Vine WeevilOtiorhynchus sulcatusDamages trees, gardens or crops
Nettle weevilPhyllobius pomaceusDamages trees, gardens or crops
Asian Oak WeevilCyrtepistomus castaneusDamages trees, gardens or crops
Strawberry Root WeevilOtiorhynchus ovatusDamages trees, gardens or crops
Common Leaf WeevilPhyllobius pyriDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Mountain_pine_beetle
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-24.