This is actually a Spittlebug infestation.

Looking like lots of tiny bubbles, this substance will normally appear in the plant where the leaf attaches to the stem or where two branches meet.

From my understanding its actually a nest, and helps keep them warm and protects them from changing temperatures.

Incidentally Spittlebugs actually do very little to the plant. They do suck some of the sap from the plant, but rarely enough to harm the plant (so I've been told), and this bubble like structure serves mostly to hide the adult and young Spittlebugs.

The little insect down near the corner of the one bubble is actually deceased and in a Spiders web.

I promise nicer photos from now on...