Ash Bark Beetle

Pest Description

• adults: ~ 1/6 inch long; dark with white to yellow scales; clubbed antennae
• larvae: white grubs with no legs and a brown head capsule

Host Plants, Diet & Damage

• ash
• feed on sapwood and phloem layers under the bark
• typically attack smaller branches, but can attack the trunk
• prefer highly stressed trees
• leaves above the damaged areas will turn color and die
• if the main stem is attacked, tree death may occur
• create small round holes in limbs
• galleries can be found under bark
• can introduce fungal pathogens

Biology, Life Cycle & Damaging Life Stage

• overwinter as late-stage larvae under the bark or as adults in bark notches
• larvae and adults become active in mid- to late-spring
• adults mate and eggs are laid within a gallery that encircles and girdles the branch
• larvae hatch and burrow outward from parental gallery
• typically one generation per year
• adults and larvae damage limbs and occasionally the main stem

IPM Recommendations

• Control is generally not warranted.
• Remove and discard infested branches prior to beetle emergence.
• Reduce stress on ash trees.
• Apply insecticides (carbamates; pyrethroids) to the bark and branches to prevent damage to susceptible trees in areas of active ash bark beetle activity.

For more information, see our Bark Beetles fact sheet.