Hello Meredith

Yes, you are correct, this looks like the two-marked treehopper egg masses covered with the sticky white substance to protect them. At this stage they are not doing damage to the tree.

The complete article, with pictures, which I think you referenced, is here- https://bygl.osu.edu/node/566

If you want to remove the spots, rub them off with a gloved hand, being careful not to damage the tree’s bark. More control information is here-

http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/INVERT/treehopper.html

I can’t see the leaf damage clearly. Are there any insects on the leaves- especially on the backs of the leaves? Does irrigation hit the leaves such that they are remaining wet for several hours or overnight?

Please attach a picture of the whole tree, so I can see the whole canopy. Also attach a picture of several leaves showing the beginning of damage( still half green) laid out flat on a plain piece of paper, 2-3 face up and 2-3 face down. Take this close up picture in focus, and from about 5-6 inches away.

These additional pictures may help identify what else may be going on. Thank you.