How to Get Rid of Rose Slugs (Sawfly)
Rose slugs are sawfly larvae, not true slugs. They skeletonize leaves in spring. Hand-pick them, blast them off with water, remove them from leaf undersides, and treat heavy outbreaks with insecticidal soap or neem.
Despite the name, rose slugs are the larvae of sawflies, small wasp-like insects. The green, caterpillar-like larvae feed on the undersides of rose leaves in spring, scraping away the tissue and leaving a lacy, skeletonized, or windowpane appearance.
Because they are not caterpillars, products aimed at caterpillars do not affect them. Instead, check leaf undersides and hand-pick or wipe off the larvae, dislodge them with a firm jet of water, and treat heavier infestations with insecticidal soap or neem oil, coating the undersides where they feed.