Rose Slugs

by Nanette Londeree, Master Rosarian

SIGNS

Eggs singly in pockets along the margins of the leaves
European rose slug – usually found on the top of the leaf
Bristly rose slug larvae – found on the underside of the leaf
Curled rose slug – curled like a naked snail and attached to the undersides of the leaves

SYMPTOMS

Leaves with only veins and one epidermis resulting in a “window pane” appearance that may turn brown and crispy
Leaf undersides scraped, “skeletonized”
Large holes in leaves
Entire leaves eaten except the main veins

CAUSE

Immature stages of sawflies (primitive wasps): European roseslug, Endelomyia aethiops; the curled roseslug, Allantus cinctus; and the bristly rose slug, Cladius difformis

TREATMENT

Prevention:

Maintain good garden sanitation
Promote a habitat for birds
Check your roses regularly for signs of damage, and if you see them, remove the affected leaves and destroy

Elimination:

Hand pick and spray off with a strong spray of water
Use neem oil or insecticidal soaps being sure to spray both the top and undersides of the leaf
Use horticultural oil when they are first attacking – will work and is a very safe alternative
Any contact or systemic insecticide labeled for use on roses will kill the roseslugs, particularly those that contain cyfluethrin

GOOD GUY / BAD GUY?

A really big nuisance, creating unsightly foliage, potentially weakening the plant

Photos courtesy of Baldo Villegas.

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