Lawn Diseases

Lawn Diseases

Maintaining a healthy lawn can be a serious challenge for Florida property owners. Between pest problems and lawn diseases, it’s not easy to keep your grass in good shape. If you’ve noticed brown patches or other symptoms of a lawn in trouble, McCall’s lawn care services team is here to help. Below, we’ve compiled a list of the most common lawn diseases home and business owners face in the Southeast:

Brown Patch Fungus

This lawn disease is most likely to occur from November through May when temperatures are below 80 degrees Fahrenheit. Brown patch fungus is triggered by rainfall, excessive irrigation, or extended periods of high humidity resulting in the leaves being continuously wet for 48 hours or more.

How to Recognize Brown Patch Fungus

Brown Patch fungus infects the leaf area closest to the soil, eventually killing the leaf while leaving the roots intact. A soft, dark rot will occur at the base of the leaf, and you can easily pull a leaf off the stem. The base of this pulled leaf will also smell rotten.

This disease usually begins as small patches (about 1 foot in diameter) that turn yellow and then reddish-brown, brown, or straw-colored as the leaves start to die. Patches can expand to several feet in diameter. It is not uncommon to see rings of yellow or brown turf with apparently healthy turf in the center. Turf at the outer margin of a patch may appear dark and wilted.

Note: Brown Patch fungus is often confused with herbicide damage on St. Augustine grass, as herbicide damage may cause the same overall symptoms of yellow or brown patches. The leaf may still pull out of the leaf sheath, but the base of the leaf will not be dark or rotten.

Helminthosporium Leaf Spot

The Helminthosoporiusm leaf spot fungus affects all warm-season turfgrasses, but it is usually most serious on Bermuda grass. At any given time of the year, at least one species within this fungal group can be isolated, meaning leaf spot can occur all year long. However, as a general rule of thumb, the leaf spot disease occurs during mild, wet periods in fall through winter.

How to Recognize Helminthosporium Leaf Spot

Leaf spot symptoms tend to vary with each pathogen and host pair, ranging from pinhead-sized, solid brown to purple-colored spots to expanded lesions with bleached centers that wrap around the leaf blade.

Severely infected leaves turn purple or reddish-brown, giving the turf an overall purple cast. Distinct patches or patterns to the disease are usually not obvious, but “melting-out” can occur under severe infections—causing large areas of your turf to grow thin, turn tan, and die.

Grey Leaf Spot

This fungal disease, primarily affecting St. Augustine grass, is most commonly observed from late spring to early fall, especially during prolonged periods of rainfall. Excessive applications of quick-release nitrogen fertilizer enhance disease severity, as does excessively compacted soil.

How to Recognize Grey Leaf Spot

Initial symptoms include small pinhead-sized spots that are olive-green to brown. These enlarge and form circular to oblong spots that are tan to brown with distinctive dark-brown margins. Under humid conditions, the fungus produces abundant spores in the center of these spots, giving them a velvety gray appearance.

Many spots can occur on a single leaf, such that severely affected leaves wither and turn brown. No distinct patches are observed, but areas may appear thin. A severely affected turfgrass area may appear as though suffering from drought.

Note: Once St. Augustine grass is established in your landscape, grey leaf spot is chronic but not severe. During the summer months, individual St. Augustine grass plants will always have a few spots on the leaf blades, but the overall health of the turfgrass is not affected unless the grass is placed under severe stress. Avoid quick-release or excessive nitrogen fertilizers during potential disease development periods.

Pythium Root Rot

This type of root rot affects all warm-season turfgrass. Symptoms are likely to appear at any time of year but will always be associated with wet soil conditions. Poor drainage, excessive rainfall, and poor irrigation can make pythium root rot much worse.

How to Recognize Pythium Root Rot

Pythium root rot will result in a decline in turf quality and density, however, the turf seldom dies. Some areas or patches will turn yellow, light green, or brown.

Note: Pythium root rot can also be confused with herbicide damage on St. Augustine grass, as herbicide damage may cause the same overall symptoms of yellow or brown patches. The leaf may still pull out of the leaf sheath, but the base of the leaf will not be dark or rotten.

Call McCall Today for Advanced Lawn Disease Treatments

At McCall, our team of lawn care experts can help you identify what type of lawn disease is damaging your grass and restore your turf back to its former glory. With six premium-blended lawn care products applied bi-monthly, we will provide your unique lawn with balanced fertilization, insect control, broadleaf weed control, and turf-related disease control. Give us a call todayGive us a call today for expert lawn care services in Northern Florida!

Lawn disease information was cited from the Florida Lawn Handbook.



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