Twolined spittlebugs (Prosapia bicincta) are sap-feeding insects best known for the frothy masses produced by their nymphs and the striking appearance of the adults. They occur in lawns, pastures, ornamental plantings, and weedy field margins, and they can become serious pests in turfgrass and landscape settings. Although individual spittlebugs are small, their combined feeding can weaken plants, discolor turf, and reduce ornamental quality.
The insect gets its common name from the two reddish or orange lines visible across the dark body of the adult. Nymphs are less conspicuous because they hide in protective “spittle” masses, which are foam-like accumulations secreted from the body and mixed with plant fluids and air. This foam helps protect the nymph from dehydration and some predators.
Twolined spittlebugs are particularly favored by humid, dense vegetation and overgrown turf. Lawns with heavy thatch, frequent moisture, and lush growth often provide ideal habitat. In such settings, populations may build enough to cause visible injury, especially during warm seasons.
The “Foam-Maker” of the Turf: Twolined Spittlebugs
The Twolined Spittlebug (Prosapia bicincta) is a “noxious” and highly recognizable xylem-feeding insect found across the Southern United States. While a major pest of coastal bermudagrass and centipedegrass, they are a high-priority “O” pest for Tucson and Southwest homeowners managing lush turf or ornamental hollies. These insects are famous for the “spittle” produced by the nymphs—a soapy, frothy mass that protects them from the intense Arizona sun and predators while they drain the plant’s structural fluids. In the Southwest, a heavy infestation can turn a vibrant green lawn into a squishy, “squelching” brown patch in just a few weeks.
Identification: The “Frothy” Nursery
Identifying Twolined Spittlebugs requires looking for “bubbles” in the grass and spotting the dark, striped adults. For Pestipedia.com users, the orange stripes and the “spit” are the primary diagnostic keys:
- The Adult: A robust, oval “froghopper” (8mm to 10mm) that is jet black with two bright orange-to-red horizontal stripes across the wings. They have a blunt, frog-like head and are powerful jumpers.
- The “Spittle” Clue: Look for white, frothy masses (resembling human spit) at the base of grass blades or on the stems of hollies. If you move the bubbles aside, you will find a small, creamy-yellow or green nymph inside.
- The “Eyes” of the Nymph: The nymphs have prominent dark eyes that contrast sharply with their pale bodies, making them look like “bug-eyed” versions of the adults.
- The “Squelch” Test: In Arizona lawns, if the grass feels unusually “squishy” or wet underfoot even when you haven’t watered, you likely have a high population of spittle-masses hidden in the thatch layer.
The “Phytotoxic” Yellowing and “Thatch” Collapse
The “noxious” impact of the Twolined Spittlebug is more than just sap loss; it is a toxic reaction to their feeding:
- Phytotoxic Saliva: As the bugs feed, they inject saliva that is toxic to the plant. This causes the grass blades to turn yellow, then purple, and finally brown, mimicking a severe drought or “heat-scorch” strike in the Tucson summer.
- Structural Wilting: Because they feed on the xylem (the water-conducting tissue), the plant loses its ability to stay upright. Infested turf will look “flat” and matted, regardless of how much you water.
- Honeydew and Mold: Like aphids, the adults excrete honeydew. In the Southwest, this leads to Sooty Mold on the lower leaves of ornamental shrubs, which blocks sunlight and stunts growth.
U.S. Turf and “Thatch-Management” Strategies
In the United States, managing Twolined Spittlebugs is a game of Humidity Control and Thatch Reduction. They are “moisture-dependent” pests that cannot survive in dry, clean turf.
- The “Thatch” Audit: For Pestipedia.com users, the #1 U.S. defense is Power-Raking or Dethatching. These bugs hide in the thick layer of dead grass (thatch) where moisture stays trapped. In Tucson, keeping your thatch layer less than 1/2 inch thick removes their “nursery.”
- Irrigation Timing: Avoid evening watering in the Southwest. Watering in the early morning (4:00 AM to 7:00 AM) allows the turf canopy to dry out during the day, making the environment too hostile for the nymphs to maintain their “spittle” bubbles.
- The “Soapy Water” Flush: If you aren’t sure how many bugs you have, mix 2 tablespoons of liquid dish soap in a gallon of water and pour it over a square yard of turf. The bugs will crawl to the surface within minutes for easy counting.
- Mowing Height: In the Arizona summer, keep your grass mowed to the “U.S. Standard” height for your species (usually 2–3 inches). Scalping the grass or letting it grow too long both create stress points that the spittlebugs will exploit.
- Targeted “Soft” Sprays: If an outbreak occurs, Neem Oil or Insecticidal Soaps are effective, but they must be applied with high water volume to penetrate through the protective “spittle” bubbles and reach the nymph underneath.
Identification
Adults are about one-quarter inch long and usually black or very dark brown with two orange or red transverse stripes across the wings. Their wedge-shaped bodies and hopping behavior resemble leafhoppers, but the color pattern is distinctive. Nymphs are pale yellow to greenish and softer-bodied, remaining hidden inside masses of frothy foam near the crown of grasses or on stems.
The foam itself is one of the easiest diagnostic features. It may appear as small spit-like clusters at the base of turfgrass, on stems of ornamentals, or around low-growing vegetation. When the foam is parted, the nymph is usually visible inside.
Life Cycle
Twolined spittlebugs lay eggs in plant tissue or in protected areas near host vegetation. Eggs overwinter in some regions and hatch when conditions become favorable. The nymphs begin feeding soon after emergence and immediately produce protective foam. They pass through several immature stages while remaining associated with the spittle mass.
After completing development, adults emerge and disperse. Adults continue to feed on host plants and may move between turf, ornamentals, and surrounding weeds. Depending on climate, one or more generations may occur per year. Warm, humid regions often support more prolonged activity.
Damage and Impact
Both nymphs and adults feed by removing plant sap. Feeding injury in turfgrass appears as purple, white, or yellow streaking at first, followed by browning and declining vigor when infestations are heavy. Because the damage can resemble drought stress or disease, twolined spittlebugs are sometimes overlooked in early stages.
In ornamental landscapes, feeding may cause reduced vigor, discoloration, and patchy decline, especially on plants already stressed by environmental conditions. Turf may thin significantly in localized patches where populations are highest. Persistent infestations also reduce the visual quality of lawns and may increase maintenance costs.
Prevention and Control
Good turf management is one of the most effective preventive tools. Reducing thatch, mowing properly, and avoiding excessive irrigation make conditions less favorable for spittlebugs. Weedy areas and dense groundcover near turf can harbor populations, so vegetation management around lawns is also useful.
Monitoring should focus on foam masses near the base of plants and on adult activity during warm months. In small areas, strong water sprays can sometimes disrupt nymphs and remove foam. Biological control from natural predators may provide some suppression, especially when insecticide use is minimized.
If chemical treatment is needed, timing is important. Nymphs are often easier to target before adult dispersal becomes widespread. Treatments should be combined with cultural improvement rather than used alone, as poor lawn conditions will continue to support reinfestation.