Each year I find some branches of the younger Garry Oak trees that I have planted on the farm to have these small brown pillbox-like galls of an insect parasite . Usually the branch will die in the following year. I am attempting to get it identified. Also the branches of the trees these are found on often have deep scratches as if a bird was trying to get under the bark?? I think that leads to the weakening of the branch. I have saved one top leader of a Garry Oak tree like this by coating the damaged section with grafting paste.
Margot Moser of Nanoose bay, suggested that these galls are likely made by the Honey gall wasp Disholcaspis eldoradensis. A light colored, cylindrical (8mm in diameter), flat-topped gall caused by a cynipid gall wasp.
I am not so sure and a look at the reference on California Oak Galls by Joyce Gross made me think it may even be Disholcaspis chrysolepidis
Phylum Arthropoda – Arthropods
Subphylum Hexapoda – Hexapods
Class Insecta – Insects
Order Hymenoptera – Ants, Bees, Wasps and Sawflies
Superfamily Cynipoidea
Family Cynipidae – Gall Wasps
Tribe Cynipini
Genus Disholcaspis
Species ?? Gall Wasp
