Wild Rose Mossy Galls: Robin's Pincushion Gall Wasp

Identifying Mossy Galls with Larvae on Wild Rose in Vancouver

Wild rose (survivor from dead red rose) gets mossy clumps after blooming containing white larvae. Owner cuts them off but wants identification.

Diagnosis: Robin's Pincushion Gall

• Caused by gall wasp laying eggs late summer on wild roses
• Larval saliva creates plant growth chemical → ball formation
• Grubs feed inside through winter, emerge spring
• DOES NOT HARM the rose

Ecological Benefit

Gall wasps = beneficial. Feed on dead/decaying matter. Leave galls alone or remove for aesthetics only.