- adults: large, 1 3⁄4 – 2 1⁄4 inches; reddish brown, relatively smooth with deeply notched antennae
- larvae: up to 4 1⁄4 inches long and about 3⁄4 inch in diameter; legless and whitish in color
Host Plants, Diet & Damage
- sweet cherry, peach, apricot, other stone fruits, cottonwood and other ornamental trees and shrubs
- larvae feed on roots, reducing the tree’s ability to take up water and nutrients
- larval feeding can open up trees to root rot pathogens
- feeding in the root crown and upper roots can girdle trees
- cause limb dieback and overall reduce tree vigor
- infestation and damage are worse on sandy soils
Biology, Life Cycle & Damaging Life Stage
- overwinter as larvae in the roots or soil
- pupate in spring
- adults emerge and fly July to September
- eggs are laid in soil near host trees
- larvae move into the soil and feed on roots working their way upward toward the root crown
- in the third year, larvae pupate near the soil surface next to root crowns
- one generation is completed in 3 years
- larvae are the primary damaging stage
- Manage trees to improve or maintain overall health.
- Monitor beetles with a pheromone and bucket light trap.
- Monitor trees for canopy dieback.
- Apply an insecticide (carbamate; pyrethroid) to the lower trunk and soil to target adults and inhibit egg laying.
- Apply a systemic neonicitinoid to the root zone to suppress younger larvae.
For more information, see our Prionus Root Borer fact sheet.