Okay, your two big trees with the huge acorns and leaves are Burr Oaks. They're great trees and may easily live another 75 years or even more.
Need to know what those other trees are- the ones you're having the problems with. If possible, you might catch one of the bugs in question in a jar or something and take it to a local garden center. They may recommend all sorts of synthetic chemicals to kill them off, but you can ignore that part.
Most of the time you end up with an infestation that attcks a bunch of trees, it's either a poorly-adapted tree for the area, or something in its environment has changed and has stressed the tree, disabling its ability to resist bad bugs.
Most bad bugs can be driven off with some Garlic/Pepper Tea, not to mention the stuff helps the tree nutritionally. Follow up with sick tree treatment, and if the worms are digging in the trunk, clean the holes out with some peroxide, then apply a bit of tree trunk goop.
The formulas for all these are on the site, most of which are at the top of this forum.
Depending upon what kind of bug it is, there may well be a good bug that eats them that you can release.
Keep us posted.
Shepherd of the Trees
It is not our part to master all the tides of the world, but to do what is in us for the succor of those years wherein we are set, uprooting the evil in the fields we know so that those who live after may have clean earth to till.