Spittlebug will attack yarrow, roses, shasta daisies, columbine, mums, and numerous other herbaceous plants. It is also found on grasses and arborvitae and other woody plants.
The immature insect produces a protective foam that looks like "spit." The foam helps protect the insect from ultraviolet light, predators, and insecticides.
Adults over winter, laying eggs in the spring. Spittle-covered green nymphs become obvious on various plants during the spring. Later in the summer, the brown, leafhopper-like adults are common.
Use a strong spray of water to wash the foam from the insect and knock it off of the plant. This will expose it to predators and those dislodged from the plant my die before they find their way back to the plant. Many chemical insecticides as well as insecticidal soaps are effective.