Lawn Problems

Look for lawn problems as you do regular maintenance.
Look for lawn problems as you do regular maintenance.

Healthy lawns may fall prey to a variety of nibblers, parasites, and harmfully competitive weeds. In this article, we'll help you identify your lawn's attackers and explain specific methods for controlling each type of lawn pest.

Prevention is often the best method for dealing with pests. We'll share several ideas to integrate into your lawn plan and design that will keep pests at bay. Proven methods against pests include everything from attracting beneficial insects, using non-chemical minerals, and even using beer on slugs.

Deer are a separate type of pest, and we'll give you lots of suggestions for keeping these voracious browsers from grazing away on your hard work.

For every pest from mold to bugs to weeds, there are pest repellents and killers.

Up Next

We have a guide to diagnosing and treating any problems that may crop up in your lawn. If you've got lots of ground cover on your lawn, we've got that covered, too. With our guide, you'll be able to identify any trouble spots on your lawn and take control before the pest problem runs rampant.

Think you have a lawn pest running through your back yard? On the next page, we'll teach you how to prevent lawn pests.

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Ladybugs are beneficial insects.
Ladybugs are beneficial insects.

If you've ever maintained a lawn, you know that weeds, insect pests, and other problems are inevitable. Insects and diseases thrive on plants, which have all the essentials: water and nutrients. Fortunately, there are things you can do to try to stop pests from taking over your lawn.

  • Interplant herbs and flowers with vegetables to help reduce lawn pest problems. This gives the vegetable garden a colorful patchwork look and helps confuse problem pests. The varied aromas of interplantings make it hard for pests to find their favorite food by scent. This works particularly well if you interplant with powerfully fragrant herbs and flowers such as mints, basils, lemon geraniums, garlic, or onions.
  • Attract beneficial insects. Sprinkling flowering plants amid the garden helps draw ladybugs, spiders, lacewings, and tiny pa­rasitic wasps who prey on plant-eating pests. The flowers provide shelter plus nectar and pollen, an alternative food source.

    Once beneficial insects are at home in your garden, keep them there. Remember, they can be killed as quickly as plant pests by broad-spectrum pesticides, which kill indiscriminately. It's best to avoid pesticides or use targeted pesticides such as Bt (a bacterial disease of caterpillars that won't harm other insects) to protect beneficial insects.
  • Use floating row covers to keep pests off vegetables. This simple idea works so well it's a wonder nobody thought of it years ago. Floating row covers are lightweight fabrics that you can drape over plants. They allow sun, rain, and fresh air to penetrate, but if secured to the ground with rocks, bricks, or long metal staples, they will keep flying insects out. Here are some great ways to use floating row covers:
    • Eliminate maggots (fly larvae), which will tunnel into the roots of radishes, turnips, carrots, onions, and other vegetables. Row covers keep egg-laying female flies away from the vegetables. If there are no eggs, there are no maggots.
    • Keep potato beetles from eating the foliage off potato leaves and vines. Pin the row cover edges down tightly so the beetles can't crawl under.
    • Protect cucumbers, squash, and pumpkins from cucumber beetles, which carry a wilt disease capable of killing entire vines. Since flowers of these vines need insect pollination for fruit set, the covers must be lifted for several hours at least every other day for bees to do their work.
    • Use barriers of copper strips or diatomaceous earth to keep slugs away from plants. Slugs are voracious plant eaters. They eat almost anything, ganging up on tender succulent plants and eating them down to the ground. They thrive where soils are damp, spending sunny days under rocks, logs, or mulch and coming out to eat when it's rainy or cool and dark. Any slug-control measures you use will work better if you clear out excess mulch and any dark, dank hiding places where slugs might breed.
    • Diatomaceous earth is a gritty substance that pierces the skin of soft-bodied slugs. Sprinkle it on the soil, encircling plants plagued by slugs. Use horticultural-grade diatomaceous earth, not the kind sold in swimming pool stores.
    • Copper strips, set around the edge of the garden, prevent slug trespass by creating an unpleasant reaction when touched with the mucus on the crawling slugs. Set copper strips an inch deep and several inches high, so that slugs can't get over or under.
  • Kill existing slugs by trapping them in deep saucers of beer. Slugs love beer, and that can be their downfall. Bury an empty plastic margarine tub in the garden soil. The top rim should be level with the soil surface. Fill the tub with beer (any kind will do) and leave it overnight. The slugs will crawl in and drown. Empty the tub every day or two and refill with beer until the tub comes through the night empty.
  • Spray aphids off plants with a strong stream of water. Aphids, small sap-sucking insects with soft, pear-shape bodies, cling to succulent young stems and buds. They reproduce quickly, sometimes covering stems that curl and distort in protest. Because aphids can multiply into swarms almost overnight, it's important to eliminate any that you find. This method works best on mature or woody plants that won't be damaged by the force of the water blast. Repeat every couple of days or any time you see new aphids arriving.

On the next page, we'll show you how to protect your lawn from deer.

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This deer may look cute, but it's a nuisance in the garden.
This deer may look cute, but it's a lawn problem.

While deer might be exciting visitors to your lawn, they will eat many of your plants and grasses. Deer are voracious vegetarians and will make short work of the lawn you've taken so long to perfect. There are many methods useful to repel deer.

Use bags of soap or human hair to repel deer. They seem to enjoy dining on cultivated plants and are worst in the winter, gobbling evergreens when their native food supply dwindles.

But they are also a problem in spring and summer, when they like to munch tender flowers and new growth. In fall, males rub their antlers on wood and can damage small trees and shrubs.

Deer don't enjoy strong-smelling soaps and human hair so this is one way to repel them. Simply stuff powerfully scented soap in a mesh bag and dangle it from branches about 3 feet high. You also can set soap bars directly on the ground. Replenish the soap supply frequently so it won't dissolve away or lose its smell.

You can also fill mesh bags with human hair. Hang them outside (like a furry scarecrow) so deer wonder if you are hiding in the garden. Refill bags as soon as you pull another handful from your hairbrush. If deer are a chronic problem, consider spraying plants with deterrents or erecting a fence.

Some Plants Preferred by Deer
Based on Cornell Cooperative Extension Service research, deer are particularly interesting in the following plants:
  • Apples
  • Arborvitaes
  • European mountain ash
  • Asters
  • Evergreen azaleas
  • Cherries
  • Clematis
  • Fraser and balsam firs
  • Hostas
  • English ivy
  • Norway maple
  • Phlox
  • Plums
  • Lilies
  • Redbud
  • Rhododendrons
  • Hybrid tea rose
  • Tulips
  • Winged euonymus
  • Wintercreeper
  • Yews
  • Daylilies

If despite your best efforts, you're still having problems with lawn pests, take a look at the charts on the last pages of this article to help you identify the most common pests of lawns and ground covers. If you feel uncertain about what is causing symptoms of damage, take a sample to your local garden center or your county Cooperative Extension office to have it identified.

Once you've identified the cause of the problem, you'll need to know how to control it. A change in cultural maintenance -- less water for instance -- may be the best control. Next, try organic controls.

If all else fails, the use of chemicals may be necessary to be rid of pesky lawn pests. See the next section for tips on safely using pesticides.

On the next page, you'll learn about lawn pesticides.

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When maintaining a landscape, whether lawns or ground covers, there may come a time when you need some sort of pesticide. It's wise to understand some basics about pesticides, as well as some common sense tips for pesticide safety.

Pesticides are chemicals that are used to control pests. They include insecticides, herbicides, fungicides, and others. For a pesticide to be effective, it must interfere with the normal development of the pest without doing harm to the host. This does not mean all pests will be eliminated. In fact, your pest problem might not be severe enough to warrant the use of a chemical. For instance, a few dandelions in the lawn can easily be removed by hand.

Dandelions are a common problem throughout the United States.
Dandelions are a common problem throughout the United States.

One should only use pesticides as a last resort. Wherever possible, use organic pesticides. One possibility is pesticides containing Bacillus thuringiensis (Bt), a bacteria that kills some pests but is not toxic to other animals or plants. If absolutely necessary, use toxic chemicals with the greatest care.

Pesticide safety when handling, mixing, applying, and storing the chemicals is critical. Most poisoning occurs during the mixing process. Splashing concentrated chemical on the skin or in the eyes, for instance, can be prevented by wearing long sleeves and trousers, rubber gloves, and safety goggles.

Pesticides must be stored in their original containers; never store a diluted solution in a bottle or jar. And, of course, keep all pesticides out of the reach of children. Read the pesticide label and follow the directions each time the pesticide is used. Follow the directions precisely; the proper dose and calibrations have already been scientifically calculated for the most effective use.

Insecticides are pesticides that are used to control insect pests. You'll first need to accurately identify the pest because not all insects can be controlled with one insecticide.

Insect damage is done by insects that chew leaves and roots and by insects that pierce the plant and suck sap from the plant. Insecticides that control root-feeding insects may be applied as granules with a lawn spreader or with a sprayer in liquid form. Either way, it is important to wash the chemical into the soil and prevent children and pets and wildlife from resting on the lawn for the safety period specified on the pesticide label.

Top-feeding insects, which feed on the leaves of ground covers and turf, are best controlled by spraying the pesticide and allowing it to dry on the foliage. The pesticide's effectiveness is lost if it is washed off by rain or irrigation.

Herbicides -- pesticides that control weeds -- are chemicals you'll potentially use on your lawn and, to a lesser degree, in beds of newly planted ground covers. Weeds are divided into two main categories. Perennials, which may be broad-leaf or grassy, live for many years. Annuals, either broad-leaf or grassy, live for only one season and reseed.

Preemergent herbicides are used to prevent the germination of many weed species, mostly annuals. They are often used early in the spring to prevent weeds, such as crabgrass, from germinating in late spring.

Postemergent herbicides are directly applied to newly germinated or established weeds. Broad-leaf weeds and perennial grasses are most often treated with a postemergent herbicide. Postemergent herbicides are classified as either a contact herbicide, which kills the part of the plant that it comes in contact with, or a systemic herbicide, which translocates throughout the entire plant. Systemic herbicides are most effective for perennial weeds.

Herbicides are also grouped as selective or nonselective. A selective herbicide controls one category of plants (for instance, broad-leaf weeds but not grasses). Nonselective herbicides kill any green plant the chemical comes in contact with. Nonselective herbicides are useful for controlling weeds in paths, driveways, and patios.

Be aware, however, that the slightest breeze may cause the chemical to drift to nearby ornamental plants, causing damage or death to those plants. When using a nonselective herbicide, keep the spray nozzle close to the weeds and never apply during breezy or windy weather. The goal is to control the weeds while minimizing damage to non-target ornamentals and turf.

As you can see from the suggestions outlined in this article, establishing a healthy lawn is relatively simple if you follow some basic guidelines during planting and are sure to keep pests at bay. Keep reading to learn how to identify weeds and pests.

On the next page, you'll learn about lawn weeds.

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Use the following chart to help you identify and control weeds attacking your lawn or ground cover.




Black Medic.
Medicago lupulina.

Annual. Spreading plants form a dense mat of dark green foliage that resembles clover. Small yellow flowers appear in spring, forming black seeds. It is a particular problem during dry periods.

Use a postemergent systemic herbicide when turf is not water stressed.

Common Chickweed.
Stellaria media.

Cool-season annual. It is low-growing with branching stems and small, pointed yellow-green leaves with small starlike white flowers. It actively grows from autumn through spring. Grow in thin turf and bare soil.

Use a preemergent herbicide in fall or early spring.

Crabgrass, Smooth and Hairy.
Digitaria ischaemem and D. sanguinalis.

Both are summer annuals. Thick clumps of smooth or hairy leaves with a spreading habit crowd out turf grass.

Use preemergent herbicide in spring when forsythia is in bloom.

Taraxacum officinale.

Perennial. Leaves are broad with deep notches, forming a rosette. Flowers are yellow and develop into fluffy white seed heads.

Use a postemergent systemic herbicide when plants appear; or dig by hand taking care to remove the entire taproot.

Ground Ivy.
Glechoma hederacea.

Perennial. A creeping plant with round, scalloped edges; stems are squared. Bright purple flowers appear in spring.

Easily removed by hand; or use a postemergent systemic herbicide when plants appear.

Polygonum aviculare.

Summer annual. Stems spread across the ground, forming dense mats of small blue-green leaves. Small white flowers appear in late summer.

Use a postemergent systemic herbicide when plants appear.

Portulaca oleracea.

Summer annual. Small yellow flowers appear on thick mats of small, succulent, green leaves with reddish stems. It grows vigorously in the heat of summer where lawns are thin or soil is bare.

Easily pulled and edible. Use a preemergent herbicide in spring or a postemergent contact herbicide when plants appear. It is especially troublesome in new plantings.

Red Sorrel.
Rumex acetosella.

Perennial. Green leaves are arrow-shaped; reddish brown flowers appear in late spring. Spreads rapidly by thizomes. Evergreen in mild climates.

Use a postemergent systemic herbicide when plants appear.

Oxalis stricta.

Annual or perennial. Yellow-green leaves resemble clover. Flowers are yellow and develop seedpods that eject mature seed throughout the lawn or garden.

Use a postemergent systemic herbicide when plants appear; some control is gained from preemergent herbicide in spring.

Plantain, Broadleaf or Buckhorn.
Plantago major; P. Lanceolata.

Perennial. Both plantains form a rosette of leaves, either wide or lancelike; they produce slender stalks on which the seed heads develop. Both species develop long taproots.

Dig plants to remove entire taproot; or use a postemergent systemic herbicide when plants appear.

Wild Garlic, Wild Onion.
Allium species.

Perennial. Narrow, tall, green hollow stems appear in early spring. Plant forms clumps and multiplies by underground bulblets.

Use a postemergent systemic herbicide.

On the next page, you'll learn about lawn pests.

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Lawn pests can make extra work in the yard. Knowing how to identify and control lawn pests will make your life much easier when it comes to lawn care. Use the following charts to help with pests that attack ground turf and ground cover.

Use the following chart to help you identify and control pests attacking your ground turf.



­ Control

Lawn becomes spotted with yellow or brown patches in late spring or summer. The patches become large if left untreated.

Black insects, 1/4 inch long.

Apply insecticide in spring and when larvae are feeding on stems. Water lawn to wash insecticide into the soil.

Round or irregular yellow patches in turf during hot, dry summer weather. Dead patches rapidly become quite large.

Chinch bugs.

Apply an insecticide labeled for chinch bugs as soon as symptoms appear. Re-treat lawn at three-week intervals until control is obtained.

Stunted clumps of yellow grass appear throughout the lawn.

Downy mildew.

Apply fungicide labeled for downy mildew in early spring or when symptoms appear. Mow lawn when grass is dry.

Patches of dead turf appear in early spring and again in late summer.


Apply soil insecticide labeled for use for grubs in turf in early spring and late summer. Control adult beetle population in trees, shrubs, and flowers by handpicking or with recommended insecticides when they appear in late spring and early summer.

Hollow, long, trailing ridges of soil across the lawn, followed by decline of turf. Holes that lead to underground tunnels are visible.

Moles and voles.

Control soil insect population to deplete food source of moles. Use spike-traps when pests are active.

Large patches of St. Augustine grass decline and turn yellow; individual leaves become mottled with yellow. Turf becomes thin.

St. Augustine Decline (SAD).

Plant SAD-resistant varieties of St. Augustine grass. Control aphids, which transmit the virus. Keep lawn-cutting equipment clean.

Patches of yellow or brown turf appear as winter snows melt. Deteriorating grass mats together, turning pink or gray, while white, cottony growth develops.

Snow mold.

Apply a fungicide in early spring to prevent spread. Reduce water and fertilizer in the fall to prevent recurrence.

Small patches of dead grass in spring, enlarging throughout the summer. Grass blades appear to have been cut off in affected areas. Small tunnel holes are visible in affected areas.

Sod webworm.

Spray with insecticide in the evening when feeding larvae are out of their tunnels. Repeat applications until adult moths, larvae, and symptoms disappear.

Use the following chart to help you identify and control pests attacking your ground turf.





Growing tips become distorted. Leaves curl and begin to wither. A clear, sticky substance appears on leaves that may attract ants.


Wash insects from plants with a strong jet of water; or apply insecticidal soap or insecticide labeled for control.

Ajuga, English Ivy, Turfgrass.

Leaves turn yellow, and tiny, elongated white bumps appear along stems and leaves. Small, round, brown bumps also appear. The plant becomes stunted and loses its leaves.

Euonymus scale.

Use a dormant oil spray in early spring for prevention. Cut out severly infected parts, and spray with recommended insecticide until signs of insects are gone.

Euonymus sp.

Plants show decreased vigor, and leaves become speckled from loss of color. The undersides of leaves are covered with small black specks.

Lace bugs.

Spray the undersides of foliage when symptoms appear. Use an insecticide recommended for lace bugs. Apply three times at seven- to ten-day intervals.

Azaleas, Cotoneaster.

New growth is distorted, and foliage is covered with white, powdery substance.

Powdery mildew.

Spray with a lime-sulfur fungicide at 10- to 14-day intervals.

Ajuga, Candytuft, Euonymus, Periwinkle.

Foliage has irregular-shaped holes, especially near base of plant.

Snails and slugs.

Pick pests when visible; lay a board near the infested areas for slugs and snails to hide and collect them during the day. Shallow pans of beer will lure the pests and drown them.

Ajuga, Daylily, Hosta.

Leaves lose their green color, speckled with white. A fine white webbing appears between leaves and stem, especially on young tips.

Spider mites.

Spray with an insecticidal soap; or apply a miticide three times at three-day intervals.

Cotoneaster, English Ivy, Juniper.

Now you have the information you need to identify pests, and plant the healthy lawn you've always wanted.

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