Elm Bark Beetles
Scolytus multistriatus; Scolytus schevyrewi
- Scolytus multistriatus (SM): 1/13–1/9 inch; reddish brown
- Scolytus schevyrewi (SS): 1/9-1/6 inch; reddish brown with black band across wings
- both have a “thumbnail-like” rear end with a center spine
- arvae: white grubs with a brown head capsule; no legs
Host Plants, Diet & Damage
- SM: elm; possibly hackberry
- SS: elm; host range broader in Russia
- feed on the phloem of stressed trees
- larval feeding can girdle branches or trees
- both species can vector Dutch elm disease to non-resistant elms
- without disease transmission, neither typically kills trees
Biology, Life Cycle & Damaging Life Stage
- overwinter as larvae under the bark
- pupate and emerge April to mid-May through summer
- two to three generations per year
- larvae are the damaging life stage
- These beetles are very common, but rarely damage Utah’s common Siberian elms; tolerate pest.
- Reduce stress and keep trees healthy and damage free.
- Prune dead or dying elm trees or branches and remove from site.
- If Dutch Elm Disease is a concern, use an appropriately labeled, systemic fungicide on susceptible trees.