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
GOOD GUY / BAD GUY?
A really big nuisance, creating unsightly foliage, potentially weakening the plant
Photos courtesy of Baldo Villegas.