10 Lawn Pests That Can Cause Problems
Updated: Jun. 02, 2021
Spring brings showers, flowers and — unfortunately — many lawn pests. Here's a collection of the most common invaders you may spot in your grass.
White Grubs
White grubs — aka White Curl Grubs due to the fact that they are usually curled into a half-circle shape —are the larvae of a number of different types of scarab beetles. Once fully grown, these pests don’t bother your lawn much. During their larval stage, however, they feed on turfgrass roots, severing them from the blades of grass above. If you notice patches of lawn that are turning brown and are easy to pull up, check for white grubs by pouring a bucket of hot soapy water onto the affected area. The grubs should begin to come up for air within about 10 minutes. Treat the area with an insecticide formulated for grub worms in the late summer or early fall when the pests are not yet adults but live near the soil surface, ready to emerge.
Chinch Bugs
These tiny pests can cause devastating damage to your yard, despite being so small that they may be hard to spot with the naked eye. Chinch bugs feed on the surface of your turfgrass, boring into the blades with their sharp mouthparts to feed on the sap inside and leaving toxic saliva that causes the plant to die, according to National Association of Landscape Professionals Director of State and Local Government Relations Bob Mann. Yellow patches of grass that turn brown and die rather than spring back to life when watered may indicate a cinch bug problem. Take a large metal can with both the top and bottom removed and drive it a few inches into the soil. Add water and wait for a few minutes to see if any cinch bugs float to the top. If you do spot these destructive pests, apply a broad-spectrum insecticide to get rid of them.
Sod Webworm
A type of lawn caterpillar, sod webworms (or tropical sod webworms) are most common in the late summer and fall. You can tell them apart from other caterpillars by their thick, pale greenish-brown body marked with dark spots along its length. They hatch from eggs laid by an adult moth on the surface of your lawn and feed on the blades of turfgrass, causing brown, dead patches to appear. You can tell that you have sod webworm damage if you spot ragged edges on blades of grass or skeletonized blades, caused by the caterpillars eating the green out of the plant so that only the transparent veining structure stays intact. Apply an insecticide effective against sod webworms in the late afternoon or early evening when the caterpillars are most active.
Armyworm
Larger than the sod webworm, the armyworm caterpillar is the larvae of the armyworm moth and got its name from its habit of invading in large army-like numbers, devouring everything in its path. These plump worms vary in color from green to brown or black and sport an inverted “Y” shape on their heads. Armyworm moths can lay up to 500 eggs a night, so it’s important to intervene immediately if you spot clusters of eggs, caterpillar frass — moist green fecal pellets at the base of grass leaves — or a live armyworm caterpillar or moths. Treat your lawn with an insecticide that is effective against armyworms and contains bifenthrin, acephate or chlorantraniliprole.
Cutworm
Another destructive lawn caterpillar, the cutworm is particularly diabolical. These moth larvae cut off turfgrass blades at the crown — the pale section where the shoot and root meet — and drag them into a burrow to feed, hence the name cutworm. Adult cutworm moths lay their eggs in clusters in the grass at night. Since they are attracted to light, cutworm invasions are particularly common on lawns around well-lit homes. If you spot smooth-bodied, dark-colored caterpillars with brown to black spots running the length of their backs and sides or notice patches of grass cut off at the base, treat your lawn with an insecticide containing chlorantraniliprole for long-term effectiveness.
Billbug
This pest spends its entire lifecycle wreaking havoc on your lawn. Adult billbugs (aka hunting billbugs) chew holes through individual blades of grass to deposit eggs inside. The hatched larvae then munch their way out of the plant from the inside and don’t stop until they’ve devoured the entire blade. Billbug damage causes patches of lawn to turn brown in early summer and the grass breaks off easily at the soil line when you tug on it, usually accompanied by a cloud of powdery excrement. Check for billbugs at the turfgrass roots and crown, where the legless larvae gather. To get rid of billbugs, use a suitable pesticide and target the adults in early spring before they lay their eggs and the newly hatched larvae later in the season before they can cause extensive damage. Land the final pesticide blow in the fall to kill any larvae and adults planning on overwintering in your lawn’s thatch layer.
Ants
A certain number of ants in your lawn can be beneficial, because their incessant tunneling aerates the soil and underground colonies add organic substances that bolster soil health. Too many ant tunnels, however, can dry out the soil at your turfgrass roots and leave unsightly mounds of excavated dirt on your lawn’s surface. Those mounds smother the grass plants underneath. You can try getting rid of troublesome ant nests by pouring boiling water, a mix of dish detergent and olive oil or white vinegar into the nest entrance, but you may create boggy or brown, damaged areas on your lawn. To banish ants without affecting your grass, apply an insecticide formulated specifically for ants that contains fipronil.
Fiery Skippers
With their bright orange wings spotted with black, fiery skipper adults bring colorful flair to your yard. Unfortunately, they also bring eggs that hatch into destructive larvae that eat their way through your grass, leaving small brown spots. If they’re not stopped in time, these larvae expand their grazing areas to join with those of nearby feasters, creating large dead patches across your lawn. Fiery skipper larvae are most often found in the grass surrounding flower beds because the adult moths feed on the nectar of the flowers and lay their eggs nearby. You can recognize fiery skipper larvae by their greenish-pink body and oversized black head with reddish markings. Get rid of the destructive larvae by taking the natural route with an application of beneficial nematodes or organic Bt pesticide.
Mole Crickets
Most common in the southeastern U.S., mole crickets — aka cricket moles, lawn crickets or flying moles — belong to the family Gryllotalpidae, along with grasshoppers and normal crickets. Adults grow to between one and two inches long and have large, mole-like front claws used for tunneling through the soil beneath turfgrass. These particularly unattractive critters weaken and kill your lawn by feeding on grass roots and shoots. Their burrows also push the surface layer of the soil up in small ridges that can lead to dehydration of germinating seeds and turfgrass roots. Sod Solutions’ Drew Wagner suggests using nematodes or insecticides containing bifenthrin, carbaryl, imidacloprid, gramma cyhalothrin, deltamethrin or permethrin to rid your yard of these invaders.
Spittlebugs
These small, winged insects sport two distinctive orange-red stripes across their backs and get their name from the white, foamy spittle-like substance they leave in the thatch layer of your turfgrass. Each blob contains an immature nymph. Hatched nymphs feed on the grass, causing white and pinkish-purple streaks running the length of individual blades before entire patches eventually turn yellow and brown. You can tell you have an infestation by simply walking through or mowing your grass and watching to see if a cloud of spittlebugs flies to another undisturbed section of your lawn. Although spittlebugs attack all types of turfgrass, they are most common in centipedegrass. When you spot spittlebug foam on your lawn, try washing it off with a hose and repeating the process every few days. This is often enough to keep an infestation in check. Otherwise, pyrethroid, carbaryl and cyfluthrin are the main pesticides used to control spittlebugs.
Originally Published: April 27, 2021
