This seems to happen on all my oaks every summer. Second flush of growth starts off strong, them the tips wilt or shrivel.
Don’t know what that is but the oaks on my property seem to be on radiation. Absolutely NOTHING seems to kill them and they just get bigger and bigger all the time with one HELLUVA root ball. Even as I try to kill some of them they just won’t die.
Looks like you have Japanese beetles for starters. Believe it or not they eat oaks but not just as they would their favorites.
If it’s not Japanese beetles it’s something else chewing.
As for the browning/shriveling, I would guess likely a soil pathogen or air borne fungus but I’m not sure, Bryan. Then there’s always too much water or not enough that shows signs just like that.
Dax, Since it seems to happen every year, no matter what the weather, I don’t think it’s a too much/too little water thing. I’m guess fungal.