WSU Extension


Caption: Black vine weevil adult and leaf damage
Photo by: A.L. Antonelli
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Pieris (Andromeda) : Black vine weevil
(revision date: 3/22/2021)

Characteristic damage by black vine weevils includes irregular, ragged notching of leaf margins by adults and minor to severe root and bark damage by larvae. The adult is a gray to black beetle about 2/5" long which feeds at night. The larvae feed below ground on roots or just beneath the soil surface on the bark at the crown of the plant. Bark feeding can result in girdling and plant death.
Management Options

Non-Chemical Management
  • Hand-pick and kill night-feeding adults.
  • Apply beneficial nematodes to kill larvae. The nematodes are most effective when applied as a soil drench in moist soils over 52 F. (late summer to early fall in western Washington). Read and follow all label directions carefully.
Select non-chemical management options as your first choice!

Chemical Management

Apply when first signs of notching on new leaves are noticed. Monthly applications may be needed if infestation is heavy. Cease when first hard frost occurs in late fall/early winter. Night applications are more effective. Beneficial nematodes can be ordered from certain nurseries. They can be applied to control the larval stage if soil temperatures are warmer than 52 F. Do not apply nematodes in direct sunlight and be sure soil is saturated with water before application.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bayer Advanced Vegetable & Garden Insect Spray RTS
    Active ingredient: cyfluthrin  |  EPA reg no: 72155-39
  • Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 70051-6-42697
  • Safer Brand Garden Defense Multi-Purpose Spray Conc [Organic]
    Active ingredient: clarified hydrophobic extract of neem oil  |  EPA reg no: 70051-2-42697
  • This list may not include all products registered for this use.
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Caption: Black vine weevil adult and leaf damage
Photo by: A.L. Antonelli