Backyard and Beyond

Gallia est omnis divisa in partes tres…
At the tips of a young oak, small round nestled in filamenty nests. Galls (not Gauls, pace Casesar) with exit holes. Big question in the wonderful world of galls is: what emerged, the gall inducer or the inquiline (parasite)?

Not just on the bud tips.

Possibly something in the Andricus gall wasp genus. This is a large genus. As I understand it, each species makes a unique gall. These tiny wasps stimulate the tree by chemical commands and the tree grows a gall in response. The tree is being hijacked, but not really damaged (?).

But wait! I’d originally thought this tree was a red oak but could it be be a bur oak? Will have to double check this.

If it’s a bur, then Andricus quercusfrondosus sounds like a possibility. This source notes that this species creates autumnal growths for the the agamic or asexual generation. Yes, gall wasps, which were once all called gall flies, alternate an asexual generation and a sexual generation. According to the cited piece, the agamic or sexual generation isn’t known for this species.

More complications: found a similar if not same gall on a definite red oak, which will be the subject of another day.

To summarize: galls are complicated.