- adults: ~ 1 inch; gray with black speckles and brown markings
- larvae: up to 1 1/4 inches long; white grubs without legs
Host Plants, Diet & Damage
- aspen, cottonwood, poplar and willow
- larvae feed on sapwood and heartwood
- cause structural weakness of branches and stems
- wounds allow secondary pathogens to invade
- boring holes ooze rust-colored sap and frass
- major pest of aspen trees in landscape and forest settings
- smaller diameter trees can be killed
Biology, Life Cycle & Damaging Life Stage
- overwinter as larvae in the wood
- adults fly from mid-June through August
- one generation is completed in about 3 years
- larvae are the primary damaging stage
- Avoid planting aspen at low elevation valley sites.
- Manage trees to improve or maintain overall health.
- Remove and chip/burn heavily infested trees.
- Spray Steinernema nematodes into active larval galleries.
- Apply a pyrethroid insecticide to the bark in early June.
For more information, see our Poplar Borer fact sheet.