Exit holes produced by shothole borers (Clemson University, USDA Cooperative Extension, Bugwood.org)
- adults: 1/16 – 1/10 inch; black to reddish brown
- have a “thumbnail-like” rear end
- larvae: white grubs with a brown head capsule; no legs
Host Plants, Diet & Damage
- crabapple and other fruit trees; cydonia; hawthorn; elm
- feed on phloem and sapwood
- produce frass and oozing from holes in trees
- attack cut, broken or unthrifty limbs or stems
- when beetles emerge, they leave small “shotgun” holes in the bark
- can introduce fungal pathogens
Biology, Life Cycle & Damaging Life Stage
- overwinter as larvae in sapwood chambers
- one to two generations per year
- emerge in April to mid-May
- larvae are the damaging life stage
- Reduce stress and keep trees healthy and damage free.
- Prune affected material and remove from site, or debark.
- Monitor fruit trees for signs of attack.
- 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.