My neighbor and I were chatting recently when I noticed his lawn had some dying spots. He thought it was lack of water and had cranked up the minutes on his irrigation controller.
My suspicion was a disease instead of under watering. During the summer months, Fescue turfgrass is susceptible to disease, especially in the hot inland climates of California. Heat and improper irrigation can create a warm, moist environment in which disease (Pythium Blight in particular) can thrive and spread.
Symptoms of my neighbor’s lawn:
- Dead spots did not look like a sprinkler pattern.
- Areas right next to the dying spots were bright green, healthy grass
- He said all his sprinklers were running fine.
- There were spots on the leaf blade rather than a wilting of the whole blade.
- Spray the damaged area and surrounding areas with a fungicide as soon as possible.
- Cut back irrigation minutes 10-20% and observe for several days. Adjust accordingly after that depending on visual quality of the grass.
- If you can, wait for cooler weather to replace dead spots in your Fescue lawn (October to May is preferred).
A general tip for determining if an area of established turf is getting enough water is to stick a screw driver in the ground in the affected area. If the soil is moist several hours after irrigation, likely it is getting enough water and instead you have a disease problem. If you have difficulty getting the screwdriver in the ground and the soil has no moisture, you likely have a bad sprinkler or poor uniformity between sprinklers or not running the station for enough minutes.
For more information on Pythium Blight, the most common disease in Fescue turfgrass, see this link: http://ipm.ucanr.edu/PMG/r785100711.html
Note: Hybrid Bermuda and St. Augustine are resistant to disease so this blog is focused on Fescue turf.