Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
I was watering my garden one day when I noticed some spots of white foam on my tansy plant. This was alarming because herbs are rarely bothered by insects and diseases. So I decided to do a little investigating to find out what was causing the foam and if it was harmful to my tansy and other plants. What I discovered was that I had a small infestation of spittlebugs.
What are Spittlebugs?
Spittlebugs (Cercopidae spp) are tiny insects related to aphids. They are rarely seen because of their miniscule ¼ inch size and tan, brown or black coloring. Some species have stripes. They are also known as froghoppers because their faces look a lot like frogs. The insects have wings but usually hop. They can hop up to 100 times their own length.
They are considered a pest in the garden because they feed by piercing the stems of your plants and sucking out the sap. Mild infestations of spittlebugs are not harmful to the plants because of the small amounts of sap that they consume. Larger infestations, with larger amounts of sap consumed, can result in stunted growth, wilted yellowed leaves, reduced yield and stunted fruit.
Spittlebugs lay their eggs in the late summer on plant stems near the top of the soil. The eggs overwinter and hatch in the early spring. The resulting nymphs are smaller than the adults and are a pale yellow-green color. The nymphs themselves are difficult to see because they cover themselves with spittle while they are feeding and molting into adults. You know they are there because you can see the white frothy patches where they are hiding on your plants.
What is Spittle?
“Spittle” is a misnomer because it implies the use of saliva. The so-called spittle produced by spittlebug nymphs is actually produced from the sap on which they feed. Excess sap moves through the nymphs’ bodies and mixes with a substance produced by their epidermal glands which are similar to our sweat glands. This substance enhances the viscosity of the spittle as well as stabilizes it to make it last longer. The nymphs move their abdomens up and down, forcing the spittle out of their anuses where it mixes with the air and forms the characteristic bubbles. The nymphs then use their legs to maneuver the bubbles from their rear ends to cover their bodies.
How the Nymphs Use Spittle
The nymphs cover themselves with spittle for three important reasons:
- It protects them from predators. The spittle is almost opaque so predators can’t see them. It also tastes acrid so if a predator does see a nymph or suspects there is something in the spittle, it will leave it alone because it tastes terrible.
- It protects them from temperature extremes. Most insects are cold blooded. Their body temperature is the same as the surrounding air temperature. Because nymphs hatch in the early spring when air temperatures are still highly variable, their spittle covering insulates their bodies and helps them maintain a constant, optimal temperature no matter how hot or cold the outside air temperature is.
- It keeps them from drying out. Unlike the adult spittlebugs who have a hard covering, nymphs have soft bodies which can dry out very quickly. Their spittle covering creates a moist environment for them as they feed and grow into adult insects.
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Handpick Them Off of Your Plants
An easy way to get rid of spittlebugs if you have a mild infestation is to handpick them off of you plants. Wear gloves if you are squeamish. Search your plants for both the nymphs and the adults and pick them off. You can kill them by either squeezing them to death or drop them into a container of soapy water.
Use A Hose to Knock Them Off Your Plants
While you are using a strong spray from your hose to get rid of aphids on your plants, you can also use it to knock spittle bugs and their nymphs off your plants too. A strong stream of water directed at the stems of the plants, especially where you can see the spittle infestations will wash them away. Be aware that some will come back, so you may have to spray for a few days to get rid of them completely.
Use A Spray to Kill Them
Insecticidal soaps and horticultural oils are effective in killing both the adults and the nymphs. However, the sprays could also damage your plants. Read the label carefully for application instructions for use in killing spittlebugs.
Keep Your Garden Weed Free
Keep your garden weeded to rob the insects of places to hide. The weeds also attract more spittle bugs to your garden because there will be more plants for them to eat. Another good practice is to leave a strip about three feet wide with no vegetation around your garden. This is to prevent the adults from hopping from your lawn or other vegetation into your garden. They can only hop about 2 feet.
Do a Thorough Garden Clean-up
The best way to get rid of a spittlebug infestation is to prevent it from happening in the first place. The females lay their eggs on plant stems in the late summer so a thorough garden cleanup is a must. Remove all dead plant material in the fall. Do not leave anything for the eggs to overwinter in. Then, to make sure that you get all of the eggs, rototill your garden.
Spittlebugs are usually just a nuisance in your garden. If you should have a large infestation which can damage your plants and reduce the yields in your vegetable garden or orchard, the insects are not difficult to get rid of and you can even prevent them from re-infesting your yard.
© 2018 Caren White
Caren White (author) on August 21, 2018:
As long as there are only a few, you don't need to worry.
Linda Lum from Washington State, USA on August 21, 2018:
I see this occasionally in my garden. I knew it was a bug but didn't know that they are harmful. Thanks for an informative article.