OT - any harborists here? Got a question

Que the razor comments. Wish I could help.

odie91 said:

Is this a fungal or an insect infestation?

I’m not astute enough to tell you by the pics alone.

  I don't see any insects or larva when I look closely at the leaves, fwiw...

Just because you don’t see any bugs, that doesn’t mean that they are not around.  

With the above said, when those leaves fall if you don’t remove them from the property the fungi will definitely remain and return to your tree in the spring. This is what I have been told by several folks who has pecan orchards. 

What does the underside of the leaf look like?

northGAcock said:

Have you had your shingles vaccination?

NOT FUNNY Robin!

GrillSgt said:

What does this have to do with boats?

Exactly, I want my click back! No boats here  

That appears to be a fungus. It is best to remove the dead limbs, twigs first, then in the fall, gather the leaves from the ground as soon as possible. 
Take the infected leaf, in a sealed plastic bag, show it to an arborist, and let them suggest a fungicide to help treat and eliminate the problem.
Some garden centers may be able to assist in that manner as well.
I think @SGH is correct with his suggestion on battling this type of fungus.
With the rain we have this year, it makes these types of fungi worse because the downward watering causes the fungus to "splash" and spread.
It may be as easy as three treatments prior to budding on the tree and the leaf drop zone using some sort of sulphur based spray to control this.
But do take that leaf to a county extension office, or an arborist, or a garden center, to get what you need to fight this.