Gray leaf spot is a foliar disease of turfgrass caused by the fungus Pyricularia grisea. This fungal pathogen commonly occurs on St. Augustine grass but can also be a problem for centipedegrass and bermudagrass. In Louisiana, gray leaf spot is typically observed from midsummer to early fall. Symptoms of gray leaf spot first appear as small, brownish, round to oblong spots (lesions) on leaf blades. As the disease progresses, lesions expand and become well developed with dark-brown margins and light-tan centers. Over time infected turfgrass dries out and leaf blades shrivel and die
Gray leaf spot on St. Augustinegrass
One way to reduce disease incidence and accelerate turfgrass recovery is to maintain a healthy lawn through balanced fertilization and irrigation and regular mowing. Some simple guidelines include:
In addition to cultural practices, fungicide applications may be required to achieve effective disease control. Always check fungicide labels for site application restrictions. When selecting products, homeowners must purchase fungicides that are labeled and recommended for residential lawns. When using fungicides, always remember to follow the label rates and frequency of application.
Fungicides used to manage gray leaf spot are sold under various trade names. They contain these active ingredients:
|Fungicide Active Ingredients|
For information on sample collection and submission guidelines please visit the Plant Diagnostic Center.
Download here: Louisiana Home Lawn Series: Gray Leaf Spot 3624-X
The LSU AgCenter and the LSU College of Agriculture