Problems With St. Augustine Grass in Florida in the Summer

St. Augustine grass has a green to blue-green shade and is well adapted to most areas in Florida, even areas that are high in salt (near beaches). Some of the cultivars grow well in the shade. In addition to pest problems, it does turn brown during drought conditions and during the winter. Many areas of Florida have water restrictions, but as long as you can water once per week with at least 1 inch of water, St. Augustine grass does well.

Weeds

If you have a weed problem, chances are that the turf is weak due to poor management or from pests. Control weeds with an herbicide labeled for St. Augustine grass. Pre-emergence herbicides, such as pendimethalin, benfin or atrazine, help to control crabgrass before it emerges. Pre-emergence herbicides should be applied February 1 in southern Florida, February 15 in central Florida and March 1 in northern Florida. Post-emergence herbicides are applied during the summer, if the air temperature is less than 85 degrees Fahrenheit.

Several insects affect St. Augustine lawns, but the most common insect is the cinch bug. It sucks the juices from the grass, using a needle-like beak. This causes the grass to turn yellowish-brown in patches. Cinch bugs start near sidewalks or buildings, or in areas of grass that are in full sun. Check for cinch bugs by removing both ends of a coffee can, then pushing one end into the soil near the edge of the affected area. Fill the can with water. The cinch bugs will float to the surface, according to the University of Florida, within five minutes. Armyworms, webworms, mole crickets and grass loopers also affect St. Augustine grass. Control all pests with the proper insecticide.

Nematode population peaks during late April and early May, then again in late August to early September. Nematodes cause the grass to become thin and have a weak root system. The grass might recover slowly after a good rain or irrigation, but it then has to compete with weeds. There is no cure for nematodes. You can control this pest by mowing higher, watering deeply once per week and fertilizing with potassium-based fertilizer.