Lawn Insect Pests

It’s not just people who like a nice green lawn. Several insects and mites feed on grass, and can ruin a perfectly good yard. Your best defense against lawn pests is to have a healthy lawn and to inspect it every seven to ten days for pest activity.

Chinch damage

Chinch bug damage

In your St. Augustine lawn, look for yellow or brown chinch bug-damaged areas found first in the hotter, drier parts of your landscape. Damaged areas appear as yellow to brown patches, and injury typically occurs first in grass that’s water-stressed or in full sun. If you suspect you have chinch bugs, inspect the border between the brown and green grass for the tiny, black-and-white adults. Treat with an appropriate pesticide in the spring, or try non-chemical options like reducing thatch or minimizing fertilizer use.

In a Bahia lawn, tunnels may indicate the presence of mole crickets. Mole crickets are a serious pest problem in Florida. They tunnel through the roots and eat the shoots of grass (and munch on the foliage of other plants as well). There are three species of mole crickets considered pests in the Southeast: tawny, southern, and short-winged mole crickets. Mole crickets can damage any grass cultivar, but prefer Bahia and Bermuda grass.

Fall armyworm

Fall armyworm

Their tunneling near the soil surface dislodges plants or causes them to dry out. If you suspect you have mole crickets in your lawn, you can check their presence by pouring a solution of liquid detergent and water onto a few square feet of turf. If multiple mole crickets appear, you may want to consider a control. Or you can purchase special nematodes for your soil that infect and kill mole crickets.

Fall armyworms are actually the larval stage of a moth. These small, light-colored caterpillars with dark heads will eat many types of grassy weeds and lawn grasses, including bermudagrass. They become active in late summer and early fall. They rarely kill lawns, but can do damage. Eradication with a special lawn caterpillar pesticide is most effective when used early, when the armyworms are still small and green.

In the summertime, tropical sod webworms can attack the grasses in many Florida lawns. These hungry pests can quickly make a lawn look scalped. The gray-green caterpillars grow up to an inch long and prefer feeding on St. Augustine, bermuda, and zoysia grasses. They feed at night and then curl up on the soil surface during the day.

If you think your lawn could be affected by tropical sod webworms, kneel down and check the grass blades for signs of chewing or scraping. Poke around in the grass to see if you can spot any webworms. You can also do a soap drench test to help flush out any insects hiding in the thatch. The good news is that the grass should recover from the damage, as long as you continue to irrigate it properly and keep it healthy.

Hunting billbug

Hunting billbug

Hunting billbugs are small but damaging weevils that often infest zoysia and bermuda grasses. Adults chew on the stems, rhizomes, and stolons, while larvae bore into stems and feed on roots. Heavily infested grass turns yellow and dies. Symptoms may be misdiagnosed as disease, drought, or a slow spring green-up.

If you suspect billbugs, start with a "tug test" to see if the damaged grass easily pulls free. Then look for sawdust-like debris inside the damaged grass tissue or small, legless white larvae in the plants or the top two inches of soil.

Keeping grass watered may help it tolerate light infestations. But if you find more than ten billbugs per square foot, an insecticide will be needed. Be sure to read the label and follow all instructions.

Fire ants are also a pest that lurks in the lawn. Read more about fire ants.

Insects aren’t the only cause of lawn damage. Make sure you correctly identify the problem before applying any treatments. Spot-treat only the infected areas, and remember to follow all label instructions.