WSU Extension

Hortsense

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


Biology
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

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