Maintaining a healthy, vigorously growing lawn is the best way to prevent insect outbreak in your grass. Each square foot of turf contains about 500 to 1,000 individual plants, each requiring optimum amounts of water and fertilizer, the right mowing regime, and an aerated, well-drained soil. If any of these factors are missing or in excess, the grass may become more susceptible to insects.
| Insect Type | What they are | Damage they create | How to Fix the Problem | What it looks like |
| Cutworms | Cutworms are moth larvae that hide in a lawn’s thatch during the day, then come out at night to feed. The worms are 1-1/2 to 2 inches long, with fat brown, gray, or black bodies; some are spotted or striped. You may see them curl up in the thatch if you peel back a section of damaged turf. | Cutworms leave 1 to 2-inch-wide spots of brown grass with the blades chewed evenly along the edges or eaten off at soil level. But because they are surface feeders, they are relatively easy to control. | Because cutworms hide in the thatch layer during the day, controlling thatch can help prevent cutworm infestations. Maintaining your lawn with regular feeding, proper watering, and periodic aerating or dethatching will keep thatch from building up and providing a happy home for cutworms. |  |
| Grubs | Grubs are white or yellowish and have fleshy, wrinkled, C-shaped bodies with tan or brown heads and six spiny legs. They are quite small when they hatch, but when fully grown are from 2 to 4 cm, depending on the species. | If your grass turns brown and pulls up easily in July and August, or if you notice a lot of critters such as skunks or raccoons tearing up your lawn, your grass may be infested with grubs. They cause damage to lawns by feeding on the roots of grass. | .Controls are most effective on immature grubs. For most species and locations that means July or August is the prime time to treat with an insecticide. However, because grub populations vary from year to year, you may be able to save the cost of treatment if you first sample your lawn to estimate how many grubs are present. Dig up several pieces of sod about a foot square. If you find five or fewer grubs per square foot, you need not apply grub control. The lawn will withstand the amount of feeding these few grubs do. If 10 or more grubs are present, treat your lawn for grubs. If the average count is between five and 10, whether or not to control depends on the health of your lawn, your tolerance for damage to the lawn, and presence of natural controls. |  |
| Sod Webworms | Webworms are 1/4” to 3/4” long and have a segmented body like a caterpillar that is brownish or dusty green. The segments of the body each have several dark spots with two or three stiff, spiny hairs protruding from each of the spots. | Damage first appears as dead patches scattered through the healthy grass. By the middle of the season, large parts of the lawn may be dead. Sod webworm scattered through the healthy grass are often confused with drought stress by the casual observer.Sod webworms chew the grass blades off very near the thatch layer and drag them into tunnels they build in or above the thatch. The result is patches that look like they’ve been scalped.Most severe damage shows up in July and August during hot weather. | Maintaining your lawn with regular feeding, proper watering, and periodic aerating will satisfy your grass’s need to grow strong and to better protect itself from insect damage. |  |
| Mole Crickets | Although you’ll seldom see them because they live underground, adult mole crickets are 1-2 inches long with large beady eyes, spade-like front legs, and grayish-brown bodies. | Mole crickets eat at night and can tunnel as much as 10-20 feet. You may see small mounds of soil scattered on the soil surface, or the lawn may feel spongy underfoot due to the insects’ tunnels. The grass will turn brown and die in areas where mole crickets have tunneled. | During the day, mole crickets return to burrows deep below the soil surface, which makes these pests difficult to control. Treatments are most effective when applied early in the spring or summer to prevent infestation, or at the first sign of insect damage |  |
| Fleas | Adult fleas are no larger than 1/8 inch long. They are reddish-brown, wingless insects that are laterally compressed, so they look as if they are walking on edge. They have piercing-sucking mouthparts which they use to obtain blood meals from their hosts. | Fleas thrive in warm or humid weather and can lay up to 50 eggs each day. Their bites leave nasty sores. Some people develop rashes when bit by fleas. Fleas usually just spread misery to infested households. If conditions are right, they can live up to two years, and their eggs and larvae can hide out in bedding, clothes, and tiny cracks in the house. | Treat the lawn and garden with a product labeled for flea controlTreat the perimeter of your house with a product labeled for flea controlYou need to attack fleas in all areas of the house at the same timeTreat your infected pets with a flea shampoo or other types of flea treatmentsVacuum the carpeting and furniture to remove eggs or larvae, then seal up the vacuum bag in a plastic garbage bag
Wash your linens, clothes and pets’ bedding in hot, soapy water
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| Ants | The workers are 3.0 to 4.5 mm long and medium red-brown in colour. | Lawn ant control begins with a healthy and well maintained lawn. Lawn ants will most frequently attack your lawn if it is unhealthy and stressed. They tend to be most troublesome during the hot, dry weather.The lawn ants themselves are not usually harmful to your lawn. They may actually help your lawn by feeding on aphids and lawn grub larvae.They are a nuisance to you and your pets though. | Your best defense is to keep your lawn healthy and stress free. Follow your lawn care schedule. Cut the grass the right height. Feed your lawn and soil the nutrients it needs. Water your lawn as necessary. |  |
| Chinch Bugs | Adult chinch bugs are about one-fifth of an inch long and black with white wings folded over their backs. Nymphs are yellow upon hatching then turn red with a light colored band across their abdomens. The nymphs develop into adults in 4-6 weeks. There can be 2-4 generation per year. | Both the adults and nymphs suck the juices out of the blades and inject a chemical that causes the blades to turn brown and die. Heavy infestations may completely kill the lawn. These sun- and heat-loving insects seldom attack shady lawns. They can move across an entire lawn in several days. | Regular feedings provide the nutrients your lawn and gardens need to grow strong to better protect themselves from insect damage.Water plants, including the lawn, just as they begin to wilt. Stressed plants are more susceptible to insect damage.Identify and control the problem early. |  |
| Armyworms | Armyworms are the larvae of a moth. The caterpillars are light green or tan in their early growth stage and dark green or brown in later stages. Full-grown larvae are 1-½ to 2 inches long and almost hairless. They can be identified by a series of green, yellow, or brown stripes down the length of their bodies. | They primarily eat grass blades, but will also eat some vegetables, like beans, cabbage, corn, onion, pepper, pea, and radish. Large infestations can completely defoliate a lawn in a few days. | Maintaining your lawn with regular feeding, proper watering, and periodic aerating will satisfy your grass’s need to grow strong and to better protect itself from insect damage. |  |
