The official name for these insects is the two-lined spittlebug. Spittlebugs will feed on all turf grasses, but by far, they prefer centipede turf, followed next by St. Augustine.
Both the adults and nymphs feed on the plants by inserting their needlelike beaks into the stem and sucking out juices. This can cause the grass to become bleached or yellow, then eventually wither and die if they are bad enough and the problem goes unchecked.
The symptoms are similar to the damage caused by chinch bugs in St. Augustine, but rest assured it doesn’t happen very often. Spittlebugs are really more of a nuisance than anything. Spittlebug adults are much more mobile than chinch bugs, so the damage tends to be spread out, rather than concentrated.
It seems that in the past, spittlebugs did not cause enough damage to warrant any kind of control measure, but things seem to be slowly changing for the worse. You have to monitor your grass to make sure they don’t do enough harm to warrant treatment.
Spittlebugs overwinter as eggs in plant stems, under leaf sheaths or in plant debris. Nymphs hatch in the spring and begin feeding. They exude a white, frothy mass around them that resembles spit, thus the name. It serves to protect the nymphs from dying out and from natural enemies.
The nymphs feed for about a month before becoming adults. Adults live for about three weeks and lay eggs for the last two weeks of that time. The eggs take two weeks to hatch in the summer. Two generations hatch each year.
Adult spittlebugs are about a quarter-inch long and black to dark brown. They have two bright, red or orange stripes across their wings. Nymphs resemble small wingless adults. They’re white to yellow-orange with red eyes and a brown head.
Early damage symptoms will look like bleached to yellow spots of dead or dying grass. With heavy infestations, these spots might overlap to form large areas of dead turf.
The nymphs are easily detected. Just look on the grass stems near the soil surface for their distinctive spittle masses. When they are bad you can actually hear a squishing sound as you walk across the grass. Adults fly readily when disturbed and can be flushed from the grass by walking through the affected areas. As mentioned earlier, you’ll see the most adults when you mow the grass.
On occasions, adult spittlebugs can damage a variety of ornamental plants too, particularly during late summer and fall, when populations are at their highest levels. The ornamental plants they prefer include hollies, asters and morning glory. If spittlebugs feed on woody plants, the new growth will be twisted and deformed and the leaves will have irregular brown blotches.
Spittlebug infestations can be controlled with several commonly available turf insecticides that contain pyrethroids such as bifenthrin (Ortho Max Bug-G-Gon), cyfluthrin (Bayer Advanced Multi-Insect Killer), cyfluthrin + imidacloprid (Bayer Complete Insect Killer), or lamba-cyhalothrin (Spectracide Once and Done Insect Killer). Use plenty of water to apply the insecticides because you need to move it through the thatch layer of the grass. When using a liquid insecticide, you can achieve the best volume of water with a hose-end sprayer.
We tend to have spittlebugs worse when we have a rainy summer. In a dry summer, the main problem is watering the lawn too much, but even when not watering too much, you can have quite a few spittlebugs if you have thick, lush grass that has been fertilized pretty heavily.
The nymphs need high humidity to survive. Turf with excessive thatch is much more likely to provide them the conditions they need. This occurs when centipede is mowed higher than it should be. Reducing the mowing height will cut down on the numbers.