Frothy bubbles on a plant are a sure sign that these small, triangular, brownish or greenish creatures are in residence. The froth is actually a protective coating produced by the nymphs; the adults don’t produce
bubbles. Nymphs are more or less immobile, but adults are winged and will fly or hop away if disturbed. Spittle bugs do suck plant sap, but most species are harmless though a few types can damage strawberries, holly, and pine trees.