Lawn Disease Control
Lawn Diseases & Disorders
Most lawn disease issues are pathogens and can be the most difficult turf pest to manage and diagnose. These pathogens are bacterial, Fungal, and Viral and can only be activated or develop from four factors that must be present at once in order for the disease to be active and noticeable. A susceptible host (your lawn), a pathogen, the right environment, and time.Disorders are altogether different but can appear to have the appearance as a disease problem. Most disorders are generally a result of unfavorable growing conditions or human error such as, fertilizer burn from over-applying or spilling, over-watering grass, fuel or oil spills, lawn equipment damage, improper mowing height and dull blades, drift or spillage from nonselective herbicide (round-up), and even bleach used in cleaning, and Pet urine. Disorders are not infectious and cannot be spread from plant to plant like a disease from foot traffic, rain, wind or lawn equipment.
Diseases however, are completely another issue, usually microscopic causing pathogens. It is important to know what the issue is in order to make a correct diagnosis to determine the proper plan of action. Systemic Fungicide and bactericides treatments for disease problems can get costly and will not reverse or repair the damage done but, can only prevent the further spread of the pathogens. The best approach once you know the pathogen is prevention applications in 30-day intervals beginning September 1 and ending when the night temperatures reach 40°F is the ideal time frame. That being said, per our licenses, pesticides can only be applied when there is a target pest. Not all turf grass varieties or properties contract disease, therefore we cannot treat every property for instance Brown Patch. In other words, we can only treat a problem when we have a problem and chemical treatments should only be a short-term solution.
We must be environmentally responsible. Most pathogens should be managed, controlled by keeping the lawn healthy, not over and under watering, and apply the correct amount of nitrogen. Tuft that is healthy and growing is far more resistant than weak and stressed lawns. A soil test is always a good start when starting a lawn application program to see where the soil nutrient levels are at present and what are measures need to be taken in order to bring the soil level to their most optimal levels. Not all cultivars are the same; some favor less or more PH and fertilizers levels than the others. This is important because these levels kept at their optimal level will help the turf in fighting off threatening pest in their appearance and overall health.
Note: Most pathogens are not harmful by killing the turf but, more or less make the turf appearance unsightly. Below are some of the most common pathogens we have to address in the southern lawns along with some common sense approaches to keep a healthy stand of turfgrass.
Brown Patch (rhizoctonia blight) |
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SIGNS & SYMPTOMSAs the name implies, Brown Patch appears in irregular circular areas of brown and diseased turf often surrounded by a narrow, dark brown or gray ring called a “smoke ring” which is evidence of active fungal growth. The interior may display a healthier green color. Patch size can range from a few inches to several feet in diameter. As a self-diagnosis, pulling blades of grass at the edge of the infected area. If the leaf blades can be extracted easily from the stems and appear brown and rotted at the base of the blades, it’s an indication that you have Brown Patch and should be treated quickly to stop the disease from spreading. |
Gray Leaf Spot (Pyricularia grisea fungus) |
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SIGNS & SYMPTOMSMay rapidly change, first exhibiting tiny lesions, which often go unnoticed, before enlarging to round, brown to tan colored spots measuring 2-5 cm boarding and band surrounding the infected tissue. Thinning of grass blades may occur and lesions may become so numerous on leaves they consume them altogether. In later stage development, the discoloration may turn purple to brown with a more oval-shape spot. Severe outbreaks of the disease may cause the turf grass to appear burned or scorched. |
Large Patch (rhizoctonia solani) |
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SIGNS & SYMPTOMSIrregular brown, yellow to orange patches of thin turf 1 to 2 feet in diameter, but can expand to yards. Multiple patches can merge together to form huge areas systematic turf. Reddish-brown lesion form on the leaf sheath but not on the leaves themselves. As the disease progresses, the leaf sheath and crown of the infected plant become rotten and greasy looking. |
Dollar Spot (Sclerotinia homoeocarpa) |
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SIGNS & SYMPTOMSOn closely mowed turf, small bleached white spots from 1 to 2 inches diameter develop and can look similar to chemical or pet urine burns. This disease symptom is also easily confused with the early stages of Pythium blight. On higher mowed turf the spot may expand into patches exceeding 5 inches in diameter. Early in the morning or when conditions favor prolonged high relative humidity, the white cottony of the fungus mycelia of the fungus can be seen in the infected turf patches. |
Pythium Blight (pythium aphanidermaturm) |
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SIGNS & SYMPTOMSIf humidity levels stay high, especially at night going into early morning, a white fluffy mass of mycelia may appear. Sometimes this is called the “cottony blight” phase. If conditions remain favorable, the spots may grow bigger in a short amount on time. In the early morning, a light gray ring may or may not be present along the outer edge of the spot. The spots are typically round irregular 1 inches in diameter on closely mowed turf can be up to several inches in diameter. On higher mowed turfgrass appear more suddenly. The leaves in infected spots are water-soaked, slimy to the touch and copper-colored, dark brown, or black when the disease is active. Spot can appear straw-colored or tan lesions with no distinct border between disease and green and tissue. In general the leaves in the center of the disease patches are completely blighted and appear dead. |
Fairy Ring (Mycelia Fungi) |
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SIGNS & SYMPTOMSFairy ring appears as arcs of green stimulated turf that range from a few feet to many in diameter. These rings are stimulated turf and may not be accompanied by an adjacent areas of dead or declining grass. when the turf becomes stressed, the rings may become brown. During a period of heavy rainfall, mushroom or puffball fungi may appear adjacent to the ring and persist for a few days. Fairy ring is very difficult to control or eliminate altogether. Old wood, stumps and other woody organic debris are left in the turf root zone below the surface. Some cheap topsoil, many in bulk from landscape supply centers have large portions of ground stumps and tree debris that can lead to a smaller outbreak of this disease. It is also best to avoid the manmade topsoil with high large amounts of mulch mixed in them and not use them as a base or even mix with existing soil for new turf installations which can carry the pathogen spores from old ground stumps and roots of tree s which can lead to this disease in smaller but yet noticeable volumes. |
Other Common Disease Problem in Southern Lawns
![]() Helminthosporium Disease |
![]() Spring Dead Spot |
![]() Microdocchium Patch (Pink Snow Mold) |
Good Common Sense Practices to Combat Common Lawn Disease Problems
- Proper mowing etiquette
Keeping the turf height at the recommended level and sharp mower blades are the first line of defense. Do not mow wet grass. Not only will it create ruts in the ground, stain clothing, and clog mowers, both man and machine will become disease carriers. - Pruning
Pruning of surrounding trees and shrubs in the infected areas will help to dry excess moisture caused by excessive shading. - Improve turf grass root system
Good soil drainage and core aeration reduce soil compaction and thatch accumulation to increase soil porosity. - Avoid spreading the disease
Do not walk through infected areas when it is wet, nor allow pets to roam through the wet grass. And again, do not mow wet grass. - Avoid over-watering
Remember this hint? Fungus thrives in excess moisture. Eliminate or limit watering in the evening. Morning watering is always the best time. - Encourage healthy root system
Low areas that hold water are more susceptible to disease due to all the excess moisture. Good soil drainage and core aeration reduce soil compaction and thatch accumulation to increase soil porosity.
We Provide Services to the Following Cities, Towns and Surrounding Regions of GA: