Rose Sawfly Larvae: Identification and Control

Those green, C-shaped "caterpillars" skeletonizing your Knockout rose leaves are rose sawfly larvae. They're not true caterpillars (they have 6+ prolegs), so B.t. won't work.

Effective Controls

• Organic: Insecticidal soap or pyrethrin sprays applied to leaf undersides when larvae are active (early morning).
• Contact: Carbaryl (Sevin) sprayed on entire plant.
• Systemic: Imidacloprid applied to soil in early spring before feeding starts.

Monitor closely in spring; early intervention prevents severe defoliation.

See Sawfly Identification for more photos.

sawfly damage

European rose slug (sawfly)

sawfly damage

curled rose slug (sawfly)