Ips hunteri; Ips pillifrons
- adults: ~ 1/6 inch; brown to black
- rear end of beetle is concave and surrounded by four prominent spines
- larvae: white grubs with brown head capsule; no legs
Host Plants, Diet & Damage
- blue spruce (mostly); Engelmann spruce
- feed on tree phloem
- produce pitch tubes and sawdust-like frass
- kill trees systematically from the top down
- can introduce fungal pathogens
Biology, Life Cycle & Damaging Life Stage
- overwinter as larvae (mostly) or adults under the bark
- two to three generations per year
- emerge in early spring with warming temperatures (warmer than 50 degrees F)
- males mate with multiple females creating diagnostic gallery pattern
- larvae are the damaging life stage
- Reduce stress and keep trees healthy and damage free.
- Irrigate properly.
- Remove affected material (usually tree tops) and remove from site, or debark.
- Monitor nearby spruce trees for signs of Ips attacks.
- If known populations are nearby, an insecticide (carbamate; pyrethroid) applied to the bark prior to beetle flight can protect trees.
For more information, see our Bark Beetles fact sheet.