August 1st – The various varieties of wasp gall that form on oak trees are necessarily seasonal. Rosy, marble and apple galls form from wasp eggs injected into leaf notes, so grown from them in spring and early summer, and by now are largely vacated and spent.
Knopper and artichoke galls form from eggs laid in acorn buds, corrupting the fruit into a gall from the crop, so don’t start appearing until late summer. Right now they’re developing well, forming a protective, curiously shaped home for the wasp larva to hatch in and develop.
Galls are fascinating things for sure, and are markers of the passing year.