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May 26, 1999

Spittlebug nymphs of both important Illinois species are present on plants throughout the state. The meadow spittlebug has a very large host range and is most important as a pest on flowers and other herbaceous ornamentals. The nymphs feed on plant sap while covered by a white foam that the nymph takes from the posterior of its body and spreads over itself, giving it the common name of spittlebug. The meadow spittlebug nymph is green and eventually grows to about 3/16 inch long. Adult spittlebugs are elongate, jumping insects that are similar in appearance to leafhoppers. Meadow spittlebug adults are colored in various brown shades and patterns. The meadow spittlebug usually causes no damage, but the spittle masses reduce the aesthetic appeal of plants.

Pine spittlebugs are present on pines throughout the state but are particularly numerous in northeastern Illinois this year. As with meadow spittlebug, the nymph forms a spittle mass but the nymph under the spittle is brown. The adult is similar in appearance to meadow spittlebug. Pine spittlebug causes a brownish area on the cambium where it feeds. Heavy infestations can cause enough necrosis to result in branch dieback. Populations that have been seen in Illinois this spring are limited to two or three per foot of branch, much too small to warrant control for damage prevention. Branches that appear almost covered in spittle probably warrant control.

The spittle prevents insecticides from reaching the nymph. If numbers need to be controlled, itís best to wash the spittle off the nymphs before applying an insecticide. With woody plants that allow higher water pressures, the water itself may wash the insects from the plants, eliminating the need for insecticide application.

Author: Phil Nixon staff at The Morton Arboretum


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