The Purdue Plant and Pest Diagnostic Laboratory

P&PDL Picture of the Week for
June 7, 2010

Bristly Rose Slug

Tom Creswell, Plant & Pest Diagnostic Lab Director and Cliff Sadof, Department of Entomology, Purdue University

Bristly rose slug (Cladius difformis)  is working its way through rose gardens this time of year.  And the extent of the damage suggests it’s not so sluggish in its feeding habit.

These small green, bristly caterpillars are about half an inch long and have a brownish head. They can be found on the undersides of rose leaves showing typical damage. They prefer to feed on the softer tissues between veins and the undersides of rose leaves first but will eventually leave only the petioles and major veins intact.

If you have only a few rose bushes you can hand pick them or clip off the affected leaves and let them fall onto newspaper spread below the bushes to capture the larvae. For larger rose plantings you may want to apply, spinosad (Fertilome Borer and Bagworm Killer), carbamate (Sevin Liquid) or bifenthrin (Talstar) if the infestation is serious. To avoid killing bees and other pollinators, don’t apply these pesticides to flowers.

Click image to enlarge

Bristly rose slug on leaves

Damage on leaves

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service