WSU Extension

Hortsense

Poplar : Poplar-and-willow borer
(revision date: 6/29/2015)


Biology
The adult poplar-and-willow borer is a black and white weevil (a flightless beetle) about 3/8" long. The larvae are white, legless, and about 1/4" long at maturity. They feed by mining beneath the bark of trunk and branches. Feeding larvae expel large quantities of sawdust-like frass (excrement) through holes in the bark. Larval feeding may girdle branches, resulting in leaf wilt and eventual branch death. Severe infestations cause lumpy, swollen bark and bark scars with exposed wood. Old wood may produce large numbers of shoots. Willows are the preferred host, but the poplar-and-willow borer will also attack poplars.
Management Options

Non-Chemical Management
  • Borer feeding results in weakened limbs. Remove dead branches and seriously infested trees for safety reasons.
Select non-chemical management options as your first choice!

Chemical Management

None recommended.

Images
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Caption: Poplar-and-willow borer adult
Photo by: A.L. Antonelli
Caption: Poplar-and-willow borer damage
Photo by: S.J. Collman