Blueberry Stem Gall - Hemadas nubilipennnis
Hard, irregular, lumpy galls on blueberry branches that are caused by a chalcid wasp, Hemadas nubilipennnis. The galls remain attached for a long time and the numerous, tiny exit holes show that these galls are multi-celled.
I spotted several of these galls on highbush blueberry (Vaccinium corymbosum) in a bog.
Hemadas nubilipennnis is a pteromalid wasp which creates stem galls on blueberry species (Vaccinium spp.). Larvae develop inside the gall. They emerge as adults in spring.