WSU Extension

Hortsense

Rose : Root weevils
(revision date: 3/10/2017)


Biology
Several species of weevils feed on roses. Adult weevils feed on the leaves, leaving small ragged notches along the edges. They may also feed on the flowers. They are wingless gray, brownish, or black beetles that feed at night. The larvae live in the soil and feed on the roots.
Management Options

Non-Chemical Management
  • Hand-pick night-feeding adults to reduce numbers.
  • Application of beneficial nematodes which kill the larvae may be useful for controlling severe infestations. The nematodes are used as a soil drench in moist soils over 55 degrees F (mid-fall in western Washington).
Select non-chemical management options as your first choice!

Chemical Management

Adult control should begin when adults emerge late May-June or when notching begins to occur on new leaves.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bayer Advanced Power Force Multi-Insect Killer R-T-S
    Active ingredient: cyfluthrin  |  EPA reg no: 72155-39
  • Bonide Systemic Insect Control
    Active ingredient: acephate  |  EPA reg no: 239-2461-4
  • ferti-lome Broad Spectrum Insecticide
    Active ingredient: bifenthrin  |  EPA reg no: 53883-228-7401
  • Garden Safe Fungicide 3 Conc - OMRI - [Organic]
    Active ingredient: clarified hydrophobic extract of neem oil  |  EPA reg no: 70051-2-39609
  • 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.
Images
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Caption: Adult root weevil damage
Photo by: E.P. Breakey
Caption: Root weevil larval damage
Photo by: A.L. Antonelli
Caption: Root weevil larvae
Photo by: A.L. Antonelli
Caption: Black vine weevil adult and leaf damage
Photo by: A.L. Antonelli