Hosts:  Oak, juniper, and southwestern dwarf mistletoe

Symptoms/Signs:  The most conspicuous evidence of infestation is the spittle-like froth that surrounds the feeding nymphs.

Biology:  Adults usually lay eggs just under the bark of twigs in summer. Eggs overwinter and hatch in spring. Nymphs feed on twigs and leaves and cover themselves with spittle. The spittle protects nymphs from drying and discourages natural enemies. Nymphs migrate to foliage in July and August where they transform to adults. Nymphs and adults feed on the sap of their hosts via their piercing mouthparts. The main natural controls include hot, dry weather that can desiccate the nymphs and a variety of natural enemies including wasp and fly parasites, ants, spiders and birds.

Effects:  When these insects are abundant, their feeding can cause discoloration and sometimes mortality of infested twigs.

Similar Insects and Diseases:  The juniper twig girdler, Styloxus bicolor, causes twig dieback and flagging on junipers, but may be distinguished from spittlebugs by looking closely at affected twigs. The twig girdler bores inside the twigs, leaving them hollow inside.

Reference:  23