One of my trees had something on the bottom of its leaves. It almost looks
like grains of sugar.

What kind of a tree? This is important. Do you see any damage or mottling on
the tops of the leaves? Is there anything that looks like a spider web or
cobweb?
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)