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St. Augustine Grass Pest & Disease

Grass image by David Prantl from

St. Augustine grass is a popular choice for lawns in the United States. A warm-season grass, St. Augustine is most active in the late spring and summer months. Though it grows naturally in coastal areas without much maintenance, when meticulously maintained, St. Augustine yields a lush lawn that is favored by many lawn enthusiasts. Understanding the basics of St. Augustine grass helps a gardener prevent and eliminate pests and disease.


Pests and diseases on St. Augustine grass can cause the lawn to die quickly. Though the damage caused by St. Augustine pest and disease problems can look similar at first, if observed closely, the effects of each type problem have distinct differences that can help a gardener determine the cause of the damage. Common symptoms of pest and disease problems in this type of grass include patches of grass that are turning brown or large areas of yellowing grass that continue to grow.


Types of pests and diseases that attack St. Augustine grass include insects, weeds and fungal diseases.


St. Augustine grass is susceptible to fungal problems, especially in the warm seasons when the weather is wet. Types of fungal invaders include gray leaf spot disease, take-all root rot, brown patch lawn disease and dollar spot disease.


When properly maintained, St. Augustine grass has few insect problems. When a lawn becomes weak due to poor maintenance practices, insect invaders can cause damage. A buildup of thatch contributes heavily to chinch bug problems. At less than 1/5 inch long, these dark brown winged insects produce offspring that suck on the tender stems at the base of Saint Augustine grass. Their saliva is toxic to plants and can cause considerable damage to a lawn.


Proper lawn maintenance can help keep pests and diseases from taking hold in St. Augustine grass. Mowing St. Augustine weekly to a height of 1 to 3 inches during the warm season can help prevent fungal diseases. Properly fertilizing St. Augustine grass to remedy deficiencies in the soil can help guard against insect pests and weed problems.


Chinch bug infestations can often look like fungal diseases in a St. Augustine lawn, so the easiest way to tell when you have a chinch bug problem is to look for them on or near the lawn in the warm months from April to September.

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