Home Lawn

Control Insects

The home lawn is an ideal environment for insects and related creatures. Some of these animals may be classified as pests. But many are harmless, and some are beneficial. It is important to know the damaging ones from the nonpests. It is also important to be able to tell the difference between insect damage and other types of damage, such as disease, drought, or nutritional problems. The following sections provide brief discussions of the most common insect pests of home lawns and the damage they cause.

Fire Ants

Fire ants are the most common insect pests of home lawns. They occur in practically every lawn in the state, and even when a homeowner manages to eliminate all fire ant mounds in the lawn, they quickly return. This is because new fire ant colonies thrive especially well in areas where they do not compete with other fire ants. Although fire ants are persistent pests, there are steps that homeowners can take to maintain lawns that are relatively fire ant free.

In terms of both cost and effort, the most effective thing you can do to control fire ants is make a broadcast application of fire ant bait at least once per season. Treatments are most effective if you apply them in the spring, but you can improve control by making additional treatments in midsummer and fall. Broadcast applications are much more effective than applying bait treatments to individual mounds. This is because broadcast bait treatments also control newly formed colonies you can’t see. Broadcast fire ant treatments are most effective when applied before large mounds are present. When using baits, keep in mind they are meant to be slow acting, to allow time for them to be taken back to the colony and fed to the queen and immature brood. It may take a month or longer to see the full benefit of a bait treatment.

You can eliminate individual mounds that survive the bait treatments with dry mound treatments or liquid mound drenches. Liquid mound drenches provide almost immediate control, when you apply them properly, but they are messy and time- consuming. Dry mound treatments are much more convenient but can take several days to work. Individual mound treatments are an effective way to eliminate large visible mounds, but they don’t work against smaller colonies not yet visible. The best approach is to combine the use of granular baits and spot treatment of individual mounds.

Chinch Bugs

Chinch bugs damage St. Augustine lawns. Although you can occasionally find chinch bugs in other grasses, they rarely cause serious injury to anything other than St Augustine. As the insects suck the plant juices, they also inject toxins that cause yellowish-brown patches to appear in lawns. These patches tend to enlarge gradually as chinch bugs expand their feeding area. If the feeding does not kill the grass, it recovers slowly and the damage lasts for a long time. Chinch bugs are sunshine-loving insects and seldom attack grass in shaded areas. Areas of St. Augustine lawns that suddenly become exposed to more sun, because of loss of shade trees, are especially susceptible to attack.

Adult chinch bugs are about one-fifth of an inch long and are black with white wings folded over the back. Newly hatched nymphs are wingless and pink to bright red with a white band across their backs. Older nymphs are black with a white line across their backs.

Check St. Augustine lawns regularly in the warm months of the year by parting the grass in several locations and watching for these insects as they move into the thatch. Another way to check for chinch bugs is to cut the bottom from an opened fruit can, imbed it an inch or so deep in a green area next to damaged turf, and fill it with water. If chinch bugs are present, they float to the top after 5 to 10 minutes. Look closely. These insects are small.

Two-lined Spittlebugs

Two-lined spittlebugs have dark maroon-colored wings with two bright red lines across each wing. Adults use their piercing-sucking mouthparts to suck sap from stems and leaves. The nymphs feed similarly but form their spittle masses deeper in the turf on the stems and stolens. The adults produce toxic saliva, which can cause significant injury to susceptible grasses. Initial symptoms include yellowing of the leaves, but heavy infestations can result in weak, unhealthy areas and even dead brown patches. Damaging infestations most commonly occur on centipede lawns.

Heavy infestations are favored by wet, rainy conditions, or by lush vigorously growing grass, and it is often the “prettiest centipede lawn in the neighborhood” that has the heaviest infestations. Lawns that are well fertilized, frequently watered, mowed fairly high, and suffer from excessive thatch are especially susceptible. Cultural practices play an important role in managing this pest. Taking steps to minimize thatch build up, keeping grass mowed to the right height, and avoiding excessive water and fertilization can reduce the potential for problems.

This insect has two or three generations per year. Adults of the second generation begin emerging in August and September, and it is normally this second generation that causes the greatest damage to home lawns. Homeowners with susceptible lawns can prevent this problem by checking for spittle masses and treating promptly, if necessary, to prevent large numbers of second generation adults. This means you need to start checking for second generation spittlebug nymphs in July.

Scout lawns by parting turf and looking for the white frothy spittle masses. Heavily infested lawns sometimes have a squishy feel when you walk across them. Treat moderate to heavy infestations with a liquid spray of a recommended insecticide. Sprays are usually more effective than granules because granules tend to fall below the target zone. Hose end sprayers are a convenient way to apply spittlebug treatments, and many home lawn insecticides are available in “ready to use” hose-end spray containers. Mow and water before treatment to improve control.

Fall Armyworms

Fall armyworms are mainly pests of bermudagrass lawns, and as their name implies, they are most common in late summer and fall. It is the larva, or caterpillar, stage that causes damage by eating the grass blades with their chewing mouthparts. Fall armyworm larvae have three pairs of true legs just behind the head, as well as five pairs of “prolegs” along their abdomen. These pests can appear as early as late June in the southern portion of the state. During high outbreak years, fall armyworms may feed on centipedegrass or St. Augustinegrass, but this is rare.

Fall armyworm adults (moths) are active at night. Female moths deposit egg masses containing about 150 eggs on grass stems or leaves. Females can lay up to 1,000 eggs. After hatching, the young larvae first feed as a group on the grass blades. The damage at this stage is slight and often goes unnoticed. But as the larvae grow, they require more food and can strip a lawn quickly. To prevent this, make regular lawn inspections, beginning in early summer.

Select locations at random throughout the lawn, and examine the grass by rubbing it briskly back and forth with your hand; then part the grass and examine the ground. If you see coiled light tan or green to nearly black caterpillars, you probably have fall armyworms. Control is much easier if you find worms early, when they are small. This also helps keep lawn damage to a minimum. Do not water turf after treating for fall armyworms, as this would wash the insecticide out of where the insects are feeding. Liquid sprays are generally more effective than granular treatments.

White Grubs

White grubs are the larvae of May beetles, June beetles, mask chafers, and other related beetles. A full-sized larva is about 1 inch long, has a brownish head, three pairs of legs, and rests in a characteristic C-shape. White grubs feed below ground, pruning the roots and causing the grass to yellow. You can easily roll or lift severely damaged sod from the ground by hand. Damage is often most obvious when infested turf doesn’t green up properly in the spring because of heavy feeding by large numbers of large, nearly mature grubs.

The adults vary in appearance, depending on species. June beetles are green, while May beetles are dark brown, and masked chafers are tan to brown. For most species, flights of adults occur early May through mid-June, and egg laying follows shortly. Because white grubs are easiest to control when small, the best time to apply white grub treatments is in mid to late summer. Check for grubs by cutting several 1 to 2-foot square samples 2 to 3 inches deep and lifting out, or rolling back, the turf square to look for grubs. Treatment is probably needed if you find an average of three to five grubs per square foot. When applying insecticides to control white grubs, water insecticides into the turf according to label directions. This leaches the insecticide into the zone where the grubs are feeding.

Mole Crickets

This insect is most common in the sandier coastal soils of south Mississippi. It is rarely a problem in the northern part of the state. Adult mole crickets are light brown, and the front legs are short with shovel-like feet that are well adapted for digging. The young, or nymphs, are identical to the adult except smaller. Damage is the result of nymphs and adults feeding on grass roots and tunneling through the turf, which also destroys roots and causes excessive drying.

These insects overwinter as partly grown nymphs, and damage is often most severe in the spring, because of heavy feeding and tunneling by large nymphs. Depending on species and location in the state, adult mole crickets fly, mate, and lay eggs from mid March to late May. Newly hatched nymphs are present in June and early July. Even though damage is not obvious at this time, this is when treatment is most effective, because small nymphs are easiest to control.

To check for this insect, mix 1 ounce of liquid dishwashing soap in 2 gallons of water, and pour this solution slowly over about 4 square feet of turf. If mole crickets are present, they will crawl to the soil surface within just a few minutes. Be sure to follow label directions for pre- and post-treatment watering when treating for mole crickets. It is usually necessary to water following treatment to leach the insecticide into the soil where the mole crickets live.

Snails and Slugs

These creatures do not damage turf, but they can be annoying. These pests, which are not insects, leave a trail of slime that appears as a silver trail when dry. They can damage bedding plants by feeding on young, tender leaves. Snails are about 1 inch long with spiral shells. Slugs vary in length from half an inch to 4 inches. They look like snails except they do not have the shells on their backs.

Snails and slugs are active at night. During the day, they can be found under mulch, in grass along sidewalks or patio edges, or under any object that may be in the lawn. Snails and slugs are best controlled with bait treatments specially formulated for these pests. When using baits, be sure to observe label precautions for use around pets and small children.

Sod Webworms

Sod webworms are the larval, or caterpillar, stage of a small night-flying moth. The moth is about 3⁄4 inch long, cigar- shaped, and gray. It has two noticeable finger-like projections on the front of the head. You may see it during the day while mowing or walking across the lawn. The moth flies short distances in a zig-zag pattern before settling quickly back into the grass.

The webworm larvae generally feed at night and prefer areas that receive plenty of direct sunlight during the day. Problems seldom develop in shaded areas. During the day the larvae may be found in small silken tunnels in grass thatch. They feed on grass blades next to these tunnels by clipping them off at the thatch line. Injury appears as small hand-sized brown patches. This insect attacks bermudagrass and zoysiagrass.

Ticks and Fleas

Fleas and ticks are carried into the lawn by dogs and cats. They are blood feeders and will bite people, as well as pets. Ticks have an extremely high reproductive potential. For example, adult females of some species of ticks may lay as many as 3,000 to 5,000 eggs in 2 weeks. Eggs take about 35 to 40 days to hatch. After hatching, the young ticks climb up grass, shrubs, or sides of the house where they wait to climb onto a passing host.

Adult fleas feed on blood, while the larvae feed on bits of organic material or dried blood in and around pet bedding areas. Thus, flea populations are normally highest near pet bedding or resting areas. High populations of fleas occasionally occur in and around home lawns.

Successful control of fleas and ticks requires controlling these pests on the pet, in any indoor areas frequented by the pet, and infested lawn areas the pet uses. Control of fleas and ticks on pets and inside homes is addressed in other Extension publications. Treatments listed in this publication are only for use outdoors in the home lawn. Do not apply them to pets or use indoors unless the label specifically indicates such uses. When treating lawns to control fleas and/or ticks, pay particular attention to areas where pets spend time resting. Often this may not be in the lawn itself but in nearby areas such as under shrubs, porches, or houses.

Control

To control lawn pests, first properly identify the target pest; then select one of the insecticides from the Insect Control Guide. Insecticides are listed by active ingredient rather than by brand name because many different brand names contain the same active ingredient. Also, brand names can be confusing, and buying insecticides based solely on brand name and what pest is pictured on the label can often lead to disappointing control. Never purchase an insecticide without first considering the active ingredient and reading the label to determine if the product is labeled and appropriate for the intended use. Time spent reading and studying pesticide labels before making the purchase is time well spent.

Controlling lawn pests depends on getting the insecticide to the target pests. Be sure to consider this when planning an insecticide treatment, and be sure you have the necessary equipment to properly apply the product you are buying. For pests such as white grubs and mole crickets, it is usually necessary to “water in” the insecticide after application. On the other hand, it is important to avoid watering and rainfall for a day or two when treating pests like fall armyworms, that feed on grass blades above the soil. Be sure to read the pesticide label and follow the application directions carefully to ensure the desired result, safe effective pest control.

For a more detailed description of lawn insects, insecticide rates, formulations, application timings, and more information refer to Extension Publication 2331.