One day you have a lush, green St. Augustine lawn and then you notice gray spots on the leaves. Soon, large parts of your lawn look like they’ve been blow-torched. What’s wrong with your lawn? The culprit is most likely a fungus called gray leaf spot.
Gray leaf spot initially appears as spots on the leaves that are round or oval, tan in color, and have a dark brown border. When the leaves are wet or humidity is high, the leaf spots turn gray and fuzzy with profuse spore production.
Newly sprigged, sodded, or rapidly growing grass is more susceptible than well-established grass. Although primarily a disease of St. Augustine grass, it also attacks centipede grass and many rye grasses.
The disease is first seen in many areas that stay moist for extended periods, such as deeply shaded areas under trees and along fences on the east side of the property. In these and other heavily infected areas, the grass will take on a scorched or burned appearance from the disease.
Here in Texas, this can be really bad news as gray leaf spot fungus thrives under hot, humid conditions which is prevalent most of the year.
The good news – with a little help, and a fungicide treatment, your St. Augustine lawn will eventually recover.
Once you get it under control, the lawn recovers relatively quick. You should start to see results in a week or two after fungicide treatments.
Full recovery is a matter of time and depends on environmental conditions and homeowner actions. The general recommendation is not to over-water or over-fertilize infected turfgrass.
However, it’s a little more complicated than that. What you don’t want to do either is water early in the morning or at night. Watering at these times is not recommended because cool and damp conditions are conducive to fungal growth. Watering at 6 a.m is okay. At 8 a.m., it is not. But watering at 10 a.m. is okay. Do not water at night.
Why the weird hours? This is because at 6 a.m., the lawn is likely already damp from dew, so a reasonable amount of irrigation won’t contribute further to the conditions the fungus thrives upon. But watering a couple of hours later will mean the leaves stay wet for hours. But by mid-morning, however, the heat of the day will quickly dry the grass out. You don’t want the leaves to stay wet any longer than you can help it.
Stressed turf will show more severe symptoms, so you should raise the mowing height to reduce stress. Catch and remove grass clippings where gray leaf spot is a problem.
Treatment lasts two to three weeks, and then you’ll have to treat again. Unfortunately, you may have to treat gray leaf spot several times, but if you can keep it at bay, and if an area’s getting plenty of sunshine, your lawn can recuperate from the gray leaf spot.
If the gray leaf spot really gets out of hand and the affected area of your lawn is in a shadier area, you’ll see the grass really go downhill and decay and become not much at all.
If you’ve seen evidence of Brown Patch and Gray Leaf Spot in your lawn, we have the right fungicides you need to treat the problem and prevent recurrence. Call us at 713-723-3950 for more information.