Seriously, go stand under any Crape Myrtle tree in California during the summer and you'll experience the same thing. Makes a mess of my truck.
If it was proven that the Old Testament manna was also something akin to dried Crape Myrtle tree bug poop, would modern Protestants be mocking the Old Testament Jews the way they are mocking these simple faithful Christians now?
My 40' Cedar of Lebanon tree does the same thing in early July and it is aphids. At least my tree has ties to the Middle East. All you Protestants can laugh because there IS a statue of Mary inside the window facing the tree; but it has nothing to do with the tree.
I do believe in many Catholic (and other) miracles but this one is just a nature calls kind of thing for the bugs.