Meadow Spittlebug

Philaenus spumarius

The adults are heavy-bodied, wedge-shaped insects about a quarter of an inch long. They are usually a mottled brown and cream, but vary from cream to almost black. They jump readily, making an audible thump. The eggs are small, yellow-to-white, elongate capsules laid in rows in a matrix under the leaf sheaths of grain stubble and in similar places. The young (nymphs) are yellow to orange. The nymphs cause the damage. They are found behind leaf sheaths, in folded leaves, or on the leaves and stems in masses of froth or spittle during late April, May, and early June. Both the nymphs and the adults may be found on a wide variety of weeds and plants, but they concentrate chiefly in alfalfa and clover fields.

Meadow Spittlebug
Figure 2. Meadow Spittlebug

Life Cycle
There is one generation each year. The insect overwinters in the egg stage. The eggs hatch in early to mid-April in central Illinois, and the last two weeks in April in northern Illinois. After the tiny nymphs hatch, they immediately start to suck sap from the plant and form the froth in which they live. At first, they are found in the crowns and the folded leaves of the plants; later, in large masses of froth anywhere on the plant. From one to several nymphs may be found in a mass of froth. The nymphs mature in June. The adults feed on a variety of plants until late August, when they congregate in clover and alfalfa fields to lay their eggs. Egg-laying continues through September.

When abundant, spittlebugs stunt plant growth by suncking the sap. They may cause losses in yield varying from slight to 25 percent or more. An average of 1 nymph per stem can decrease the yield of dry hay by 300 or more pounds per acre. To determine the need for treatment, count the spittlebugs on 50 to 100 stems selected throughout the field.

Chemical control is usually not profitable if the number of spittlebug nymphs averages fewer than I per stem. When the average is 1 or more nymphs per stem, control will be profitable if you need the hay.