St. Augustine grass (Stenotaphrum secundatum) gives your lawn a soft feel with a pleasant blue-green shade. Grown for its salt and shade tolerance, St. Augustine grass comes with a few potential problems as well, including susceptibility to some common fungal disorders. Identifying the fungal disease is essential to picking the ideal fungicide.
Brown Patch Disease
The warmer weather of summer brings fungi to existence, resulting in diseases in your St. Augustine, such as brown patch disease. This issue appears as brownish dots on the blades, which often spread in a circular pattern throughout the lawn. Many affected areas perish. Nitrogen makes the issue worse, so avoid nitrogen fertilizers through the summer if you’ve ever had a issue with brown stain. Standard use of fungicides like thiophanate-methyl or propiconazole helps regulate the disease. Follow the manufacturer’s application instructions for your particular product carefully. When you apply thiophanate-methyl, for instance, spread 6.75 pounds of the granules over 5,000 square feet of lawn with a seed spreader. Reapply every two to three weeks during the summer to help keep the disease in check.
Take-All Root Rot
Take-all root rot isn’t particular to St. Augustine grass, but that’s where it is most commonly found. Diagnose this disease by searching for spotty dead patches, which is small or big. The blades and stolons often turn brown but remain attached to the roots; they are not easy to pull off. The root processes become brown or black, and a few blades may appear yellow. The fungus usually attacks in the spring or fall, thriving in soil temperatures between 60 and 65 degrees Fahrenheit. Use fungicides that are effective against the fungus causing take-all root rot, like propiconazole or myclobutanil. The company’s directions vary by product, so follow the instructions carefully. As an instance, with a few versions of myclobutanil, mix 7 fluid ounces of the fungicide with 1 gallon of water at a garden sprayer and spray it above 500 square feet of your lawn once you begin seeing dead spots.
Gray Leaf Spot
St. Augustine is the bud most likely to suffer from gray leaf spot. Small brown spots appear on the blades, which turn gray with a purple or yellow halo as the spots get bigger. Affected blades sometimes host a light gray cottony growth as well. In acute cases, large areas might appear like they are suffering from drought, with a gray cast and scorched look. Alternative distinct fungicides like azoxystrobin and triadimefon, because the fungus may develop immunity if only one fungicide can be used consistently. Manufacturers provide specific instructions for their products, like spreading 2 to 4 pounds of azoxystrobin granules above 1,000 square feet of lawn every 2 weeks in the summer. In most cases, it is possible to treat your lawn for grey leaf spot as a preventative measure, before you see any problems with grey leaf spot.
Other Issues
Several other fungal diseases sometimes affect St. Augustine grass, however, the effects are not normally severe. As an instance, downy mildew appears as white or yellow streaks that run vertically in the grass blades, and it typically appears in wet springs. After the weather dissolves and the higher temperatures of summer approach, downy mildew tends to disappear without demanding fungicidal treatment. Generally, good lawn maintenance helps maintain the grass healthy enough to fight bacterial disease before it becomes a problem. Mow the grass regularly, cutting it up to 2 1/2 to 3 1/2 inches high. Water infrequently, like once a week, but deeply therefore the water penetrates 4 to 6 inches deep. Watering in the morning helps the grass blades dry before nighttime falls, which helps prevent fungal growth. When using any kind of fungicide, wear long trousers, a long-sleeved shirt and eye protection. Follow any security advice about the tag and keep children and pets from the region while you’re employing the chemicals.