Spittle Bugs – the Mystery Foam Source
By George Giltner, Master Gardener
From the name, spittle, you know what to look for – a spit-looking mass on vegetation. This frothy mass is excreted by yellow-brown nymphs mainly on grasses and ornamentals as defensive protection against predators and desiccation. Below the froth, the nymphs insert piercing mouth parts into the plant consuming large amounts of plant juices. They go through 4 instars before reaching adulthood. Populations expand during wet humid climate periods and retract during drought.
In Louisiana, they can be found on grasses like St. Augustine, centipede, rye, Johnson, coastal Bermuda, and small grain crops. Usually spittle bugs are not a problem, unless large populations develop under wet environmental conditions. Pyrethroids can be used for control. Also look for them in vines like honeysuckle and morning-glory and in ornamentals like holly, aster, and redbud where their feeding results in white blotches on the leaves. They are most active in the morning to avoid the heat and drying conditions of hot afternoons.
The common two-lined spittle bug adults look like large black leafhoppers. They are easily identified with two large red or orange stripes across their triangular-shaped body. If you get close enough, notice the small red eyes.
The adults only live for three weeks, with females laying eggs during the last two weeks of their lives. Eggs laid in the fall, overwinter in grass sheaths and ground debris.
The Pecan spittlebugs, Clastoptera achatina, are more of a problem insect, especially where pecans are grown. The nymphs become active after bud break in the spring by feeding on young buds and later on tender shoots and nutlets. Heavy populations can cause terminal bud death and immature nut shedding. Infections can be recognized by white bubbly masses on terminal buds to dried yellowish masses on young nuts. The adults are small, 4 to 5 mm, and yellowish brown in color. Therefore they are hard to detect in pecan trees.
So the next time that you see those frothy masses on your plants, shrubs or trees, look for the larvae spittlebugs underneath. At least you will know the source was not a rabid animal or from human origin.