Lawn enemies fall into three main categories:
- Insects and diseases
- Weeds
- Carelessness
None of these enemies is formidable; all are easily routed with the correct “ammunition.”
The wise gardener builds a strong “home guard” – a good turf—through proper fertilization, mowing, and watering. When trouble strikes, recognizing the enemy’s nature is half the battle.
Japanese Beetle Grubs
If patches of grass grow brown in ever-widening areas, Japanese beetle grubs may be at work. When the injury is severe, the turf can be lifted readily—almost rolled back like a carpet—and grubs may be seen underneath the brown patches’ outer rim, where the grass is still green. These grubs feed on grass roots, cutting them 1” to 2” inches below the surface.
This type of injury is most likely to occur in August, September, and mid-to-late spring. Newly damaged turf wilts quickly on hot days. In some cases, prompt, thorough watering will enable the turf to reroot and survive.
Once the Japanese beetle grubs have been detected, your method of attack is to use an insecticide. Applying six pounds of 10% percent DDT or five pounds of 5% percent chlordane dust per 1,000 square feet will check the grubs as soon as water moves the insecticide into the feeding zone.
Moles
Another underground enemy—the mole—is less subtle in his attack. Soft linear mounds of earth recognize his presence pushed up as he burrows his way underneath the sod.
You can “deflate” these tunnels by pressing the sod down with your foot hut. By the following morning, they may be “inflated” again, or new tunnels will be visible.
It is sometimes possible to see the mounds of earth undulate as the mole runs through them. One way to do away with Mr. Mole is to spear him by plunging a pitchfork into the ground as he runs through the tunnel.
Many successful methods of routing moles have been reported. For example, mothballs or naphthalene flakes placed in each runway are said to help keep them away.
Roy E. Shepherd, a well-known rose grower and FLOWER GROWER contributor reports that arsenate of lead spread over the area, “one pound per 100 square feet, destroys the moles’ food supply grubs, insects, etc.
l so that they move on to greener pastures.” Another FLOWER GROWER reader places one end of a garden hose in the mole run, the other end in the exhaust pipe of his car, then turns on the motor.
Mole Nots and cyanogens dust are available for mole destruction, as are special mole traps which spear the enemy as he goes through his underground passageway.
Ants
Ants do not feed on the lawn but build unsightly hills that mar the lawn’s beauty. According to the manufacturer’s directions, they can be killed using ant baits or traps.
Chinch Hugs
Chinch bugs may injure lawn turf severely in summer and are usually more troublesome in dry weather.
The first sign of their presence is the dying of turf grasses in localized areas. Injury tends to be more severe in warm locations near barriers—such as pavements and buildings.
The use of three to five pounds of 10% percent DDT or five pounds of 5% percent chlordane dust per 1,000 square feet will control the chinch bug.
Treatment must be made whenever the tiny young insects are abundant. The adult chinch bug has a characteristic white marking on the wings.
Weeds
Weeds are the greatest of all lawn plagues. So why are some lawns more persistently troubled than others? Often the weedy lawn needs a vigorous turf cover to help combat the weeds.
A weak sparse turf leaves the entire job of combating weeds up to you through hand-weeding or using chemicals.
The wise gardener enlists the lawn itself to aid in the struggle. Many persistent weed problems will disappear when the grass becomes vigorous enough to crowd out the weeds.
The most common causes of thin, weak turf on typical bluegrass-fescue lawns are inadequate fertilization and close mowing.
Applications of 20 pounds of 5-10-5, or similar fertilizer, per 1.000’ square feet are recommended for early spring and September. Proper use of fertilizer and high mowing will make the typical Kentucky bluegrass lawn a vigorous competitor against weeds.
A minimum cutting height of 11” inches is recommended, and a height of 2” inches is better.
Crabgrass
Crabgrass is the most detested of lawn weeds. It is encouraged by close mowing, inadequate fertilization, light flashwaterings, overwatering, and late spring or early summer fertilization. Remove grass clippings and any other practice that weakens the permanent grasses.
Whenever crabgrass becomes a pest, consideration should be given to changing faulty maintenance procedures. Usually, generous fertilization in spring and fall, in conjunction with high mowing, will eliminate a crabgrass threat in two to three years.
Chemicals help eliminate crabgrass. Phenyl-mercury acetate and potassium cyanate preparations are most commonly used. Follow the directions and make trial applications to a small section of the lawn.to become acquainted with the type of results you’ll get.
Chemicals can be very helpful or very disastrous. Therefore, they should only be used with careful consideration of the instructions, as excessive application rates can severely damage turf.
Broad-leaved weeds, such as buckhorn, dandelion, plantain, and sorrel, are readily eliminated by 2,4-D preparations. The chemical 2,4-D can be purchased in most garden supply stores. However, use care to keep this chemical away from valuable garden and ornamental plants, for they may be severely injured.
Heavy Traffic
Traffic should be minimal when the soil is moist because severe soil compaction occurs. Traffic also should be distributed over the lawn area as uniformly as possible. Avoid walking over the same route so paths will not be worn over the lawn surface.
When turf has been injured by trampling and soil compaction, it may be desirable to temporarily close the area to traffic.
Usually, these sections of the lawn are small, and it may be possible to use a hand fork in the spring to loosen the soil without destroying the grass. In larger areas, a verifier will be helpful.
Do not use the lawn for disposal of water containing solid alkalis. Burned areas are sure to result.
Shade
Turf grasses require sunlight for growth. Wherever shade is intense, turf grasses may grow poorly. The red fescues and rough-stalked bluegrass, Poa trivialis, are tolerant of shade.
Often it is challenging to grow good turf in the shade, although red fescues and Poa trivialis are used. When this is the case, examine the situation for ways of improvement.
High mowing strengthens grass grown in the shade and is very effective for advancing shady turf areas.
Trees can be pruned higher to permit more sunlight on the lawn. Often this can be done without detracting from the beauty of the landscape. Frequent light fertilization of shaded areas also may improve growth without creating a crabgrass problem.
Summer Failures
Lawn grasses may fail quite suddenly in hot weather. There is no single reason for such occurrences. Disease, insects, heat, drought, and an excess of water may be singly responsible or combine to cause failure.
Careful examination of the turf when the injury occurs may reveal the responsible factors. Still, it usually will take time to determine reasons for failure several weeks later.
Examine the turf closely when the first signs of summer injury are apparent. Disease injury usually shows as circular brown spots ranging in size from a silver dollar to several feet across. These may appear very suddenly on any portion of the lawn. Control measures are discussed below under “Bentgrass.”
Lawn grasses may suffer severe injury in dry, hot weather. Yet it is likely that many diseases and insect injuries are blamed on heat or drought. On the other hand, a healthy mature lawn should survive 25 to 50 days of dry weather without damage.
The more drought-resistant grounds are those where the grass has been cut high, and the soil has been adequately limed over the years. Lawns seeded in the spring will likely suffer severely during the first summer. Fall-seeded properties are usually more tolerant of heat and drought.
The first signs of drought damage occur on warm exposures or near trees. Many lawns turn brown in dry, hot weather and will recover almost entirely with the first cool, moist weather.
If the property appears to be suffering from a lack of moisture, examine the soil. If it is dry to a depth of 4” or 5” inches, apply water slowly to these areas until the humidity reaches a depth of 5” or 6” inches.
Remember that all sections of the lawn may not need water at the same time. Avoid overwatering, as excess. Moisture may ruin a property as quickly as drought.
Bentgrass
The fine quality of bentgrass makes it the aristocrat of turf grasses. Unfortunately, bentgrass turf may have an excellent appearance and suddenly develop a large amount of brown or dead spots from disease attacks, which may occur frequently or rarely.
These outbreaks can be controlled effectively by carefully timed treatments with mercury fungicides.
Since therapy before the disease attack is required for good results, fungicide applications should be made regularly every 7 to 14 days when the disease is likely to occur. The correct use of fungicides involves considerable effort.
And many people choose to take a chance on escaping conditions. Whether fungicides are used or not, the bentgrass lawn should be kept healthy—a primary step in controlling the disease. The moderate use of fertilizer and minimum water use reduces the amount of disease trouble.
Control of thatch on bentgrass lawns is essential in keeping the turf healthy. Thatch is an accumulation of stems.
Leaves and roots at the surface of the soil develop over the years. It hinders water movement into the ground and is associated with severe disease outbreaks. Any cultivation treatment that mixes thatch with soil, or a vigorous raking, helps reduce the amount of accumulation.
44659 by Ralph E. Engel