Willow

Disease

Marssonina leaf & twig spot

Rust

Twig blight (Venturia)

Insect

Carpenterworm

Poplar-and-willow borer

Satin moth

Spiny elm caterpillar

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Caption: Poplar-and-willow borer adult

Photo by: A.L. Antonelli

Willow : Poplar-and-willow borer

(revision date: 6/29/2015)

Use Integrated Pest Management (IPM) for successful plant problem management.

Biology

The adult poplar-and-willow borer is a black and white weevil (a flightless beetle) about 3/8" long. The larvae are white and legless and mine beneath the bark and in trunk and branches. Feeding larvae expel large quantities of frass (sawdust-like excrement) through holes they keep open in the bark. The feeding larvae may girdle branches, resulting in leaf wilt and eventual branch death. When mature, larvae are approximately 1/4" long. Severe infestations cause swollen, lumpy bark, bark scars with exposed wood, and sometimes considerable production of shoots from old wood. Willows are preferred, but the borer will also attack poplar species.

Management Options

Non-Chemical Management

Remove seriously infested trees.

Select non-chemical management options as your first choice!

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

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

WSU Extension

Hortsense