White Spots & Holes on Knock Out Roses: Rose Slug (Sawfly) Damage

Second-year Knock Out roses show white spots and holes in leaves. No visible pests on leaf surfaces or undersides.

Diagnosis: Rose Slug (Sawfly Larvae)

Rose slugs feed on leaf undersides, creating windowpane-like transparent spots that become holes. They're small, green, caterpillar-like, and easy to miss.

Control

• Use any rose spray labeled for rose slugs or sawflies.
• Thoroughly spray leaf undersides and soil around base (they hide there when not feeding).
• Repeat as needed—multiple generations per season.

Early detection and targeted spraying prevent significant defoliation.