Description Roseslugs are a type of sawfly. They are usually best identified in their larval stages, particularly since this is the stage when most damage occurs. There are three types of roseslugs that plague our roses, all somewhat different inhabit and life cycle. The Curled Roseslug larva is metallic green with white dots, and tends to be found curled up in a tight spiral on the underside of the leaf.
Adults are wasp-like insects, about inch long, shiny black with yellow markings.
The most common roseslug seen in our area is the European roseslug. Life cycle European roseslugs overwinter as pupae in cocoons in debris or soil. The eggs soon hatch and the larvae begin to feed on the upper surface of the leaf. When the larvae are fully grown, they drop to the soil to prepare their cocoons. European roseslugs have one generation per year.