Who Spit on My Plants?

Spittlebug bubbles on lavender stem.

It’s the season for spittlebugs (Cercopidae family). You may see what looks like spit on plant stems but don’t blame it on the neighbor kids or the guy next door. The spittle, or foam, is made by a tiny insect that's so small you will likely never see one. The bug likes lavender, strawberries, salvia, rosemary and a variety of other plants. The spittle is a protective covering for the nymph of this insect. It attaches itself to a plant stem, then secretes a liquid that turns into bubble-like foam, around itself. This foam hides the spittlebug from predators, insulates them from temperature fluctuations and keeps them moist.

Spittlebug eggs are laid in late summer and overwinter on plant debris. The eggs hatch in spring and the young nymphs then crawl up plants and attach themselves, then make their protective covering of “spit.” These insects do little harm to plants. They feed somewhat on the plant’s sap, but unless you have large amounts of these little clumps of spittle, there’s no need to use any kind of poison on them. The easiest control is to use the spray from a garden hose and wash them off the plant with plain water onto the ground, where predators can easily eat them.

The "spit" is a protective coating around the tiny nymph inside.

So don't despair when you see the cluster of bubbles on your lavender or other plants. The spittle is made by a tiny insect to protect itself from birds and other insects. Spray it away with a garden hose and forgive it for looking like spit. Who knows what our house looks like to it?

Happy gardening!