What has happened to my grass?
Last week it looked so green, healthy, and strong. This week is looks sick, is turning brown, and appears to be dying.
The answer is the dreaded FUNGUS and it is attacking lawns in the Jefferson City and Lake Ozark area. Fungus is a disease of the grass of which there are several types. It can attack every type and strain of grass if the right conditions are present for fungus growth. No grass is totally immune to all types of fungus. The primary time for fungus development in central Missouri is during the months of June, July, and August when daytime temperatures reach 85 - 90 + degrees and night-time temperatures reach 65 - 70 + degrees.
There are many types of fungus, but the two most commonly found in Missouri lawns are Dollar Spot and Brown Patch. These two fungi are capable of severely damaging or killing any grasses it attacks. Dollar Spot appears as small round spots, generally a few at first, then multiplying to several in a matter of a few days or weeks. Brown Patch is much larger than Dollar Spot and generally will produce fewer spots.
Both Dollar Spot and Brown Patch prosper in a warm and humid environment. The disease is usually caused by excessive moisture lingering on the turf for a prolonged period of time. Lawns that sit in low areas around lakes or rivers are especially prone to a fungus attack. A cool rainy period, followed by a rapid increase in temperatures creates a prime time for fungus to attack your beautiful lawn. While we cannot control Mother Nature, there are some cultural practices we can do to minimize the possibility of fungus becoming a problem in your lawn.
Dollar Spot Fungus
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Symptoms:
Round bleached out to tan-colored spots ranging from the size of a quarter to a silver dollar. Spots appear sunken. Yellow to light green lesions may appear. In the morning spots appear grayish white from mycelium.
Turf Grasses Affected:
Annual Bluegrass, Bent grass, Bermuda grass, Turf Fescue, Kentucky Bluegrass, Perennial Ryegrass.
Occurrence:
Late spring to early fall when temperatures range from 60-90 degrees.
Brown Patch Fungus
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Symptoms:
Circular patches ranging form a few inches to several feet. Turf first appears water-soaked and dark. When dry, turf withers and turns brown. Dark-colored sclerotia may be present under leaf sheath or on crown and roots. "Smoke Ring" effect may be seen when closely mowed disease patches develop grayish-black borders. Musky odor may be present.
Turf Grasses Affected:
Annual Bluegrass, Bent grass, Bermuda grass, Kentucky Bluegrass, Perennial Ryegrass, St. Augustine, Tall Fescue, Turf Fescue.
Occurrence:
Spring through fall when air temperature is above 75 degrees F, there is high humidity, and soil temperatures exceed 60 degrees F.
- Turf diseases are similar to human diseases in that the healthier a person is, the less likely he or she is to get sick. Turf grasses are the same way. The healthier your lawn is, the less risk there will be for fungus disease development. Turf professionals, like the staff at Central MO Turf Management, can assist you in developing a turf program that will keep your lawn very healthy.
- Dollar Spot is most likely to grow on turf which is low in nitrogen or not well fertilized. Brown Patch has a tendency to grow in turf that is well fertilized.
- Large amounts of thatch left in the lawn will definitely get the attention of fungus. Some people advocate leaving grass clippings on the lawn to increase organic matter, save time, and save money on mowing bills. However, over one-half inch of thatch in your lawn will increase your chances of a fungus attack. It is strongly advisable to bag the grass clippings if your lawn is prone to fungus. Periodic dethatching is also recommended to remove old thatch that has built up in the lawn.
- Irrigation should be done early in the morning as soon after sunrise as possible. Be sure your lawn drains well and does not hold standing water as fungus will grow rapidly in this condition. Never water your lawn in the evening or late at night. Water should soak into the soil and the warm sun dry the grass leaves as soon as possible after irrigation. You definitely do not want the moisture from irrigation to sit on the grass leaves during the night as this is a definite prescription for fungus. (more information on watering)
- Aeration is highly recommended on an annual basis (fall season) to allow the water to penetrate the soil where it belongs.
- Proper mowing of the lawn is also a major consideration in fungus prevention. It is recommended that a Fescue lawn be cut at 2 ½ inches; Bluegrass at 1 1/2 to 2 inches: and Zoysia cut at one inch. This procedure will help the lawn to remain healthy and green by developing and maintaining a strong root system. In addition, the grass should always be mowed with a sharp blade to avoid tearing the grass blades. A tear, rather than a cut, injures the grass blade and provides an excellent place for fungus spores to develop. Also, never cut more than one-third of the height of the grass off at one time. Cutting more than one-third of the grass blade off at any one time will also cause the lawn to develop a yellowish green color until the grass grows back out.
- If a fungus invades the grass, a lawn care professional such as Central MO Turf Management can apply a curative fungicide application to the lawn. In most cases the grass will recover in a short period of time if treated in the early stages of development. However, if not treated or not treated in the early stages of development, much of the affected area will have a high risk of dying. Re-seeding is then required.
Central MO Turf Management is pro-active with our Pro Supreme program in preventing fungus from invading a lawn. Our goal is to do everything possible to prevent fungus spores from invading the lawn and damaging the grass in any way. This program provides for multiple applications of a high quality preventive fungicide and a special blend of other products to build the health and vigor of the lawn each summer. This program will help to eliminate the possibility of fungus development in the lawn.
FINAL NOTE: If your goal is to develop a high quality or world class lawn, it is almost impossible to achieve unless both FUNGUS and INSECT programs are included in your total lawn care plan.
Other types of fungus found in this area:
Fairy Ring Fungus
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Symptoms:
Dark green or deal lines ranging from four inches to one foot wide and forming circles two to 15 feet in diameter. Several rings may appear in the same area. Mushrooms, toadstools or puffballs may also appear after rain. This fungus is not common but is very difficult to kill permanently once it attacks a lawn.
Turf Grasses Affected:
Annual Bluegrass, Bent grass, Turf Fescue, Kentucky Bluegrass, Perennial Ryegrass, St. Augustine grass, Tall fescue
Occurrence:
Early spring through late fall.
Powdery Mildew Fungus
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Symptoms:
Dark green or deal lines ranging from four inches to one foot wide and forming circles two to 15 feet in diameter. Several rings may appear in the same area. Mushrooms, toadstools or puffballs may also appear after rain. This fungus is not common but is very difficult to kill permanently once it attacks a lawn.
Turf Grasses Affected:
Annual Bluegrass, Bent grass, Turf Fescue, Kentucky Bluegrass, Perennial Ryegrass, St. Augustine grass, Tall fescue
Occurrence:
Early spring through late fall.
Pythium Blight Fungus
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Symptoms:
Circular reddish-brown spots ranging from one to six inches. In the morning, blades appear water soaked, dark, and may feel slimy. Mycelium may also be present. When dry, blades shrivel and appear reddish-brown. Infected blades collapse quickly. Turf may appear streaked.
Turf Grasses Affected:
Annual Bluegrass, Bent grass, Bermuda grass, Turf Fescue, Perennial Ryegrass, Tall Fescue.
Occurrence:
Summer when temperatures range from 80-95 degrees F.
Summer Patch Fungus
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Symptoms:
Small, irregular, blue-gray, wilted patches, three inches to a foot in diameter, that turn a yellowish-bronze. Patches may have green centers with a "frog-eye" effect.
Turf Grasses Affected:
Bent grass, Kentucky Bluegrass, Turf Fescue, Perennial Ryegrass.
Occurrence:
During warm summer months following a rainy period.
Dog Urine
No, this is not a fungus but many people mistake it for fungus. Dog urine burns the turf due to acid and dissolved salts in the urine. It is usually a circle about 6 inches in diameter. Once the damage has occurred and the brown spots are visible the grass is dead in the area of the burn and should be replaced or re-seeded.
"One of the major contributors to high acid and dissolved salt in urine of dogs is a high protein diet. High protein in a dog ration is obtained from a meat diet of table scraps, canned dog food, or dry dog food that contains high levels of dried meats or animal fats. In order to reduce the toxicity of the urine, it will be necessary to eliminate table scraps and canned dog food from the diet and feed a dry dog food containing only a maintenance level of protein. Other than a change in the diet, the only way to eliminate problems with urine killing the grass is to watch where the dog urinates and immediately poor water on the spot to dilute the toxic urine."
- Dr. Greg Popp,
Weathered Rock Veterinary Clinic, Jefferson City, MO
Hot Spots
This picture is also not any form of fungus. Central MO Turf Management refers to this condition as “Hot Spots” resulting from: thin top soil, compacted soil, and insufficient moisture. The crown of much of the grass has died from lack of moisture and very little if any of this grass will survive. Each sprig of grass is competing with other sprigs for available moisture. Also, many broadleaf and grassy weeds will germinate in areas where the grass has died and they too will compete for moisture. The eventual result of this condition will be total destruction of the lawn or portion of the lawn where the problem occurs.
*Fungus pictures from Rhone-Poulenc, makers of Chipco fungicides.