MN Lawn Pests - Diagnose and Treat Insects in Your Minnesota Lawn

Pest Insects In The Lawn
By Yardners.com
In most cases, when you have a lawn with an insect problem, you have a lawn that is in stress for some reason. Insects will bother the lawn when the grass is weak.

The solution to the problem is twofold.
First you must deal with the immediate problem; the insect causing the immediate problem.
Then you must evaluate why the lawn was in stress creating a condition in which the insect would become a problem.
There is a file for dealing with each of the insects listed on the symptoms chart below. You will find that in most cases, we give you three solutions to the immediate insect problem: a do-it-yourself solution using no pesticides, solutions using natural insecticides, and solutions using synthetic insecticides.
This table gives you a summary of the symptoms you might face that are a function of pest insectsc described in detail in the buttons on the left.
Possible Pest Insect Problems in Lawns

Possible Symptoms	Possible Cause	Solutions
Mounds appear in middle of lawn and kill grass	Ants	Many times an ant problem can be completely solved by simply forcing the ant colony to move to another location in or outside of the yard. There are a number of techniques and products available for dealing with ants. We present those solutions in three groups, do-it-yourself solutions using no insecticides, using natural insecticides and using synthetic insecticides. All solutions presented are considered safe by our authors for use in the home landscape. There are some products on the market that we do not recommend because so many effective options exist that are less toxic to the environment.
Mounds appear in middle of lawn and kill grass	Moles	Moles are basically good guys. Moles eat lots of undesirable soil-dwelling grubs and beetles and aerate the soil in lawns and planted beds. The benefit of their eliminating grubs is somewhat offset by the fact that they also eat earthworms, which are valuable soil builders. Fortunately in a healthy landscape that is not a problem. The healthier your soil, the more earthworms it contains, and the less chance the mole is going to upset the population balance of earthworms.
In the fall you may see round, bare areas in the lawn. Armyworms look like caterpillars and can appear in large numbers, and will eat the grass right down to the soil. Armyworms usually feed at night. The damage they do resemble that caused by sod webworms. If you lift up the dead sod in these areas, you'll find armyworms in the soil.	Armyworms	The Fall Armyworm (Spodoptera frugiperda) is the caterpillar of a gray mottled moth. It is about 1 and 1/2 to 1 3/4 inches long and has a somewhat hairy body. They are somewhat larger than the sod webworm. It is usually brown, but may be green or black, and has a black head. Three yellowish white hairlines stretch down its back from head to tail. You'll find a dark stripe along either side, and below that a wavy yellow line splotched with red. A white V or Y marks its head. Only one generation occurs each year in the North. The eggs are covered with hair and are laid in clusters of 50 to 150. Young white larvae hang from threads or curl up in leaves. Fall armyworms are found throughout most of North America, except in the far north. The adult is a gray, mottled night flying moth with a 2 inch wingspan. The adults migrate south for the winter. Emergent Times - In the spring, swarms of moths fly North and lay eggs, and the caterpillars begin their devastation in the fall. Nature's Armyworm Control System Nature's Armyworm Control System If your yard has good diversity of plants, you feed songbirds, and you don't use any broad spectrum insecticides the following beneficial insects and songbirds love to eat aphids and if in sufficient numbers will keep armyworms under control. Beneficial insect predators - Assassin Bugs, Bigeyed Bugs, Ground or Tiger Beetles,Rove Beetles, Spiders, and Tachinid Flies eat armyworms for lunch. Songbird predators - Robins and Starlings love armyworms.
In June or July damage is noted where the grass appears brownish or there may appear small circular patterns that turn yellowish and brown. Dead sections of grass will lift away easily from soil.	Billbug	Billbugs are a particular problem of Kentucky bluegrass lawns. Members of the weevil family, the adults have long snouts that end in a set of mandibles. Adult billbugs are 1/4 to 1/2 inch long and brown or gray. the larvae do the most damage to the stems of grass plants, however adults will also cause some stem and leaf blade damage. The larvae are small legless white grub-like creatures with a yellow-brown head. They look much like a grain of puffed rice. They feed on stem tissue causing infested shoots to turn brown and die. Emergence Times - Billbugs overwinter as adults and emerge in April or May. In late May, females lay eggs in lawngrass stems above the crown in May and June. In June, larvae move into the soil and feed on roots and rhizomes. They remain near the soil surface feeding near the thatch layer when it's moist. As soils dry, they go deeper. In July, adults appear. These over-winter starting in October in leaf litter.
In August and early September, suspect chinch bugs when you see large, distinct, circular patches, primarily in the sunny areas of your lawn, that turn yellow, then brown, and then die. These patches often first appear near sidewalks, driveways, streets, and other borders such as railroad ties or flagstones that reflect heat onto the lawn. The yellowish spots eventually spread outward into the rest of the lawn, showing the greatest damage at their centers where the chinch bugs congregate.	Cinch Bugs	Adult chinch bugs are only about 1/5 inch long, about the size of a ladybug. They have black bodies marked by a black triangular pad which separates white, folded wings. Immature bugs, called nymphs, are reddish colored. Chinch bugs cluster in lawns down among grass blades near the crowns of the grass plants and suck juices from their tissues. Their feeding causes grass to appear yellowish and sometimes stains the grass red. These bugs thrive in hot, dry weather, becoming active when temperatures are in the high 70s. Chinch bugs are called hairy chinch bugs in the North. The pests are so small and inconspicuous that they can destroy a lawn right beneath your eyes without being noticed. Aside from lawns, chinch bugs have long been notorious as serious pests of grain crops such as wheat, rye, oats, barley, sorghum, and corn. Their Growth Stages - Chinch bugs damage turfgrass in each of their stages of development from nymph to mature adult. Overwintering adult chinch bugs hibernate in the thatch and upper layer of the soil under the lawn. They become active in March, laying eggs in the thatch and around the crowns of grass plants. The second generation causes the most problems from August to September, when Northern grasses are stressed from the summer heat. Lower than average temperatures plus moisture retards chinch bug activity. Chinch bugs breed once a year in Canada and New England but twice a year in the mid-Atlantic region. They occur throughout most of the country, but are worst in the Midwest, East, and South. In the Northeast they are most fond of Kentucky bluegrass and red fescue. In the South, southern chinch bugs are particular pests of St. Augustine, Bermuda and zoysia grasses. They may remain partially active throughout the winter. If you grow St. Augustine grass, plant the chinch bug-resistant ‘Floratam’ variety, or switch to centipede grass which is not attacked by chinch bugs. Most common turfgrass targets of chinch bugs: · Bent grass · Bermuda grass · Kentucky bluegrass · Red Fescue · St. Augustine grass · Zoysia grass Turfgrasses resistant to chinch bugs: · Centipede grass · St. Augustine grass varieties ‘Floratam’, ‘Floralawn’, and ‘Floratine’.
Usually you don’t see fire ants first; you feel the stings	Fire Ants	Fire Ant Stings Are Very Painful Usually you don’t see fire ants first. Either you see their colony’s mound and avoid getting near it or you have inadvertently stepped on a mound and you feel the pain of dozens of almost immediate bites. In infested areas, fire ant stings occur more frequently than bee, wasp, hornet, and yellowjacket stings. Often a fire ant mound is not yet easily discerned, and so the stings can come very unexpectedly. You can also get stung by stepping on one of the lateral tunnels to the mound. Ants defend these tunnels as part of their mound. A person who stands on a mound or one of its tunnels, or who leans against a fencepost included in the defended area, can have hundreds of ants rush out to attack. Typically, the ants can be swarming on a person for 10 or more seconds before they grab the skin with their mandibles, double over their abdomens, and inject their stingers. Although a single fire ant sting hurts less than a bee or wasp sting, the effect of multiple stings is impressive and impossible to ignore. Each sting results in a pustule and intense itching, which may persist for as much as 10 days. Infections may occur if pustules are broken. Some people have allergic reactions to fire ant stings that range from rashes and swelling to paralysis, or anaphylactic shock.
Cats and dogs bring fleas in from outside, you see them in rugs and on white socks	Fleas	Fleas can be a problem in the yard as well as inside the home. Because treating flea problems indoors requires different techniques and materials, this file deals only with cat and dog fleas found outside in the yard. The most troublesome flea species are the cat flea (Ctenocephalides felis) and the dog flea (C. canis). About Fleas Adult fleas are small, hard-shelled, shiny brownish insects little bigger than the head of a pin. They are severely flattened from side to side, which helps them move about easily on a furry animal. They are wingless, with piercing-sucking mouthparts and powerful hind legs for jumping. Their Growth Stages Fleas feed only on blood, and the females deposit their eggs only after a blood meal. Cat fleas will reproduce on some other animals such as rats and raccoons, but generally in most home landscapes, the cat or dog is the only source for that one meal before reproduction. The eggs are laid on the animal or in the pet’s favorite outdoor resting places. Flea eggs are white, abut 1/50 inch long. Only a few are laid at any one time but several hundred may be laid during the flea’s lifetime. The eggs hatch in 2 to 14 days. The larval stage lasts 1 to 5 weeks, during which the larvae live on bits of organic matter. They don’t bite pets or humans. When full grown, the larva forms a cocoon, which becomes dirty and so blends in with other dust on the floor or in the soil. Adult fleas usually emerge from the cocoon when a host such as your pet is nearby. They may feed several times a day on the animal, but they can live for weeks without a blood meal. Outdoors, fleas are most abundant during humid, rainy summers and are more common outside in the southern United States than in the north.
In late spring the webworms’ feeding causes small brown patches, 1 to 2 inches in diameter, to appear in the lawn where the thatch layer is exposed. These dead patches may be round spots or may look like lightning bolt streaks running across the lawn. By midsummer the damaged areas join together into larger patches. Infested lawns look their worst by July and August.	Sod webworm	In their caterpillar stages, sod webworms (Crambus species) are serious pests of lawn grasses. The caterpillars are about 3/4 to 1 inch long. They have dark shiny brown heads, but their color varies from greenish to beige, brown or gray, depending on the species. They have 4 parallel rows of distinctive dark spots along the length of their abdomen. Long, stiff hairs protrude from these spots. The adults are buff-colored or grayish-brown moths with a wingspan of about an inch. They fly in the early morning or late evening in a jerky zigzag pattern, just a few feet above the lawn, which explains another common name for these pests, “lawn moths.” They fly up from their hiding places when tall grass is mowed or shrubbery is disturbed. They are also attracted to lights at night. Sod webworms are found throughout the United States and in southern Canada. Their Growth Stages Sod webworm moths don't feed on lawn grasses, but they drop their eggs into the grass as they fly. After 6 to 10 days, the eggs develop into very hungry caterpillars. These immediately begin feeding on grass blades, and are active only at night. As they feed, they build silk-lined tunnels in the thatch near the soil surface. During the 35 days or so that the webworm lives as a caterpillar, it can eat about 4 square feet of grass. By late fall the webworms are nearly mature. They overwinter curled up in the soil as pupae and emerge as moths in the spring to begin feeding and laying eggs as soon as the soil temperature rises--in late April to early May in Northern and Midwestern states. First generation larvae feed from late June to the end of July. The second generation can be a more serious problem because the host grasses are usually dormant or under stress and can't replace damaged foliage. In the warmer areas of the country, webworms may produce up to 3 generations, during May, July, and September. In Western and Southern states, webworm generations may overlap, with all life stages--eggs, caterpillars and moths—present in the lawn at the same time.
Grass seedlings in newly seeded lawn disappear, cut off at the base of the grass blade	Cutworm	“Cutworm” is an general term for the larvae, or caterpillar stage, of more than 200 species of moths. Also called owlet moths or miller moths, these insects are serious pests of many crops and ornamental plants in all parts of the United States. Their larvae, cutworms, are many different colors--gray, brown, bronze, black, greenish-white or red--but all are fat, soft worms, with coarse bristles sparsely covering their bodies. Cutworm larvae are different sizes as well, but most have grown to 1 or 2 inches long by the time they are interested in your plants. If you touch cutworms, they quickly roll up into a ball. You probably won't see them since they feed at night and hide in the soil during the day. Cutworms develop into moths, sometimes known as “miller” or “owlet” moths. These rather plain, two-inch-wide grayish or brown moths hover around outdoor lights at night and may even wander indoors. Moths adults don't harm your plants because they feed solely on flower nectar. During the day they hide in debris and in other sheltered places. In the fall, the females lay their white eggs near the soil, most frequently on weeds and grasses. During the growing season the moths lay eggs on crop plants soon after they have sprouted After the eggs hatch several weeks later, the tiny larvae burrow into the soil, emerging at night to feed on plant stems. Later they build small cells in the soil to pupate. They may spend 1 to 8 weeks in these cells, or even overwinter there, depending on the species. Some species may hatch up to 4 generations a year in warmer areas of the country.
Starting in June or early July you see irregular brown patches of grass. Increasing gradually over the season, the brown spots are most extensive by fall after a full season of grub activity. Suspect a grub problem where turf appears scorched. The sod lifts up easily in these spots because the roots have been destroyed.	Grubs	Grubs are perhaps the most hated pest insect in the country. They are often blamed for lawn problems in error. This file should help you be sure that your problem is in fact caused by grubs and then if that is the case, we will help you solve that problem once and for all. “Grub” is a catch-all term for the larval, or worm, stage of many kinds of beetles. May beetles (also called June bugs), Japanese beetles, masked chafers, billbugs, Asiatic garden beetles and others all are grubs in the soil prior to emerging as beetles during the growing season. In the Northeast, Japanese beetle grubs are the most common pests of residential lawns. Masked chafers are most common in the Midwest, and June bugs are most common in the West. Where Grubs Are Found Grubs are plump whitish colored worms that grow 3/4 to 1-1/2 inches long. They have 3 pairs of legs and tan heads with large, brown-black mouth parts. They rest in a characteristic C-shaped curl just under the soil surface in planted areas or turf, where they feed on roots of ornamental plants and lawn grasses. In vegetable gardens grubs are not usually a problem because they are exposed when the soil is frequently disturbed by cultivation and planting. However, they may infest new planting areas that have been established where there was once lawn. Growth Stages Of Grubs An understanding of a grub’s life cycle--which may span 1, 2, or even to 3 years, depending on the species--is the foundation of a successful control strategy. During the summer the adult beetles leave the soil at dusk and fly about during the night feeding on tree and shrub foliage and mating. At dawn, the beetles fly back to the soil to lay their eggs. The eggs hatch in 2 or 3 weeks, and the new grubs feed on roots and other underground plant parts until early fall. Then they burrow deep into the soil to hibernate below the frost for the winter. As the weather and soil warm up in the spring, grubs migrate back toward the surface to resume feeding on plant roots. They feed all season long and then dig down again to overwinter. Next season they come back up, feed, pupate, and emerge as adult beetles.
Areas of lawn turn brown and die; small mounds of soil become evident	Mole Cricket