WSU Extension


Black mold 
Black spot 
Botrytis bud and twig blight 
Brand canker 
Bullheading (cold damage) 
Common canker 
Crown gall 
Downy mildew 
Powdery mildew 
Leafcutting bees 
Redhumped caterpillar 
Root weevils 
Rose aphids 
Rose galls 
Rose leafhopper 
Rose midge 
Spider mites 
Tobacco budworm 
Western spotted cucumber beetle 

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Caption: Mossy rose gall
Photo by: R.S. Byther
Rose : Rose galls
(revision date: 4/23/2014)

Insects can cause two types of rose galls: spiny rose gall and mossy rose gall. The spiny rose gall is caused by tiny cynipid wasps. They produce small hard internal caverns armed with stout, sharp spines on the exterior. The galls usually occur on the surface of leaves, but they sometimes occur on stems. These rose galls do not appear to harm the plant. Spiny rose gall develops exclusively on wild roses. Some people consider them to be rather attractive nuances. The mossy rose gall is also caused by cynipid wasps. This gall resembles a highly filamentous and spongy twig gall that can exceed the size of a golf ball. It contains numerous caverns with resident wasp larvae. It also appears harmless to the plant, and occurs on domestic roses only.
Management Options

Non-Chemical Management
  • Hand remove or prune galls if aesthetics are a concern.
  • Allow parasites to control the wasp population.
Select non-chemical management options as your first choice!

Chemical Management

None recommended


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Caption: Mossy rose gall
Photo by: R.S. Byther
Caption: Rose spiny leaf gall
Photo by: R.S. Byther