Spittlebugs
These sucking insects (family Cercopidae) can at least occasionally be found on almost any plant. They are also called froghoppers because adults rest with their head elevated. Only about one-half dozen species of spittlebug are known in California. These include Clastoptera lineatocollis and those discussed below.
Identification
Where spittlebug nymphs suck and feed on plant tissue (xylem fluid), they surround themselves with frothy white excrement beginning during the second instar. One or more nymphs can occur in a single spittle mass. Nymphs are stout and commonly pale green, orange, or yellow.
Adult spittlebugs readily fly or jump when disturbed. They are stout and commonly brownish, gray, or tan insects about 1/3 inch long or less. They resemble leafhoppers (family Cicadellidae), which include sharpshooters. However, spittlebugs lack the long, continuous rows of spines found along the hind tibia (longest leg segment) of leafhoppers.
Spittlebugs are discriminated from leafhoppers and other true bugs (Heteroptera) by two stout, thornlike spines along the outer length of hind tibia. Spittlebugs also have a whorl of many spines at the end of the tibia near the tarsi (feet). See Sharpshooters/Spittlebug for an illustration comparing the leg spines of leafhoppers versus spittlebugs. To help you discriminate between these and other types (families) of insects with similar-looking adults see Distinguishing Among Sucking Insects That Resemble Each Other.
Meadow spittlebug. Philaenus spumarius feeds primarily on broadleaved herbaceous plants, but it also occurs on woody, deciduous species. At least 400 hosts are known. Adults are robust and blackish, brown, tan, yellow, or a mottled mix of these colors. Females lay brown to white eggs in rows at plant nodes. Nymphs are pale green to yellow and occur mostly hidden beneath a foaming mass of spittle.
Meadow spittlebug requires cool, humid or moist conditions so it historically has been common in coastal areas. Its populations have declined in recent years and this is believed due to global warming.
Western pine spittlebugs. Aphrophora permutata is one of several Aphrophora species that feed on conifers and nearby herbaceous plants. It is especially common on Monterey pine and other pines in coastal areas of California. Other hosts include Douglas-fir, fir, hemlock, spruce, and various herbaceous broadleaves.
Nymphs are mostly black, brown, or dark greenish. Adults are dark brown to orangish and may have an indistinct diagonal white line across the back. Adults can be up to 1/2 inch long. For a detailed discussion of this pest consult The Biology of Aphrophora permutata and Some Observations on Aphrophora canadensis Attacking Monterey Pine in California.
Life cycle
Spittlebugs develop through three life stages: egg, nymph and adult. Adult females use their knifelike ovipositor to lay eggs singly into thin-barked branches and succulent, green shoots or in crevices of plants. Each female commonly lays one to several dozen eggs in or on hosts.
After hatching, nymphs suck and feed on aboveground parts or near the soil line on the root crown. They begin producing and surrounding their body with spittle during the second instar and grow through four increasingly larger instars. Nymphs remain mobile throughout their life and move to feed in a different location if the quality of the plant part on which they feed declines. Each nymph feeds for 1 to 3 months. The last instar darkens and develops wing pads before maturing into an adult.
Adult spittlebugs are relatively long lived, and each can feed and move among plant parts for up to 6 months. Overwintering occurs as tiny eggs on or in stems or needles. Spittlebugs commonly have one or two generations per year in California.
Damage
Feeding by abundant spittlebugs can distort host tissue and slow plant growth, but this is primarily a problem on herbaceous species. On hosts such as pines the egg laying wounds of adult females when abundant can cause shoot tips to die back. Spittlebugs’ obvious and occasionally abundant masses of white foam on foliage and stems may be annoying, but they do not seriously harm established woody plants in landscapes.
In certain crops spittlebugs may be important vectors of plant pathogens, such as the Xylella fastidiosa bacterium that causes oleander leaf scorch of oleander and other woody landscape species, Pierce's disease of grapes, and variously named diseases in other crops. However glassy-winged sharpshooter and certain other leafhoppers are the main vectors of X. fastidiosa. The potential importance of spittlebugs in spreading this pathogen in gardens and landscapes may be unknown.
Solutions
Adult spittlebugs are commonly fed upon by birds. Nymphs are preyed upon by assassin bugs, minute pirate bugs, syrphid larvae, and various harvestmen and spiders. Eggs and nymphs are attacked by various parasitic wasps. Although the importance of their natural enemies is not well known, biological control of spittlebugs is generally considered to be not important.
Ignore spittlebugs or wash nymphs off with a forceful stream of water. Spittlebugs are more likely to become abundant on woody plants when they migrate from nearby herbaceous hosts. Cut spittlebug-infested weeds in the spring before the insects mature and spread.
For more information see Spittlebugs of Canada (PDF), which includes many California species. Adapted from the publications above and Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide, University of California Statewide Integrated Pest Management Program (UC IPM). | 
