Community ClicksWho does not appreciate the feel of a lush green lawn under their toes? Almost every American household has some lawn area, no matter how small. Lawns, however, are susceptible to diseases that can degrade their appearance and even kill them.
On the North Olympic Peninsula, we have two main lawn diseases — red thread and fusarium patch. Both diseases are caused by fungi that attack the roots and shoots of grass, killing them in spots.
“Red thread” is characterized by the grass turning red or pink as the fungus grows along the leaves. It is common on fescue and ryegrasses but may also appear on bentgrasses. The disease develops in late fall through late spring when the humidity is high and temperatures are cooler. It frequently occurs on poor draining soils in winter when the water table rises and is closer to (or even on) the surface of compacted soil.
“Fusarium patch” is common on bentgrass, but also can affect other types of turfgrass. It appears as small, round brownish patches that can coalesce into larger areas. As with red thread, cool temperatures and high humidity promote development of this disease.
How can we avoid fungal diseases in our lawns? First, avoid or correct conditions that are favorable to these diseases.
All lawns need good soil. Have the soil tested every two to three years to determine if any nutrients are low or absent. Correct deficiencies, but do not overfertilize as this can encourage disease development.
Master Gardeners recommend having your soil tested by the Clallam Conservation District in Port Angeles. Phone 360-452-1912 Ext. 109 for more information.
Ensure good drainage and improve compacted soil areas by perforating the area with an aerating machine or pitchfork in early spring and fall.
Avoid overwatering grass; deep, infrequent watering is best. Water in the morning so grass can dry quickly.
The type of grass you plant or have in an existing lawn is also critical. Four types of cool-season grasses grow well in Western Washington: turf-type perennial ryegrasses, fine-leaved fescues, bentgrasses, and turf-type tall fescues.
Grasses such as fine fescues do well on poor soils and tolerate shade and drought. They do not wear well but are resistant to common diseases and do not form thatch (a layer of dead material that builds up at the base of grass leaves).
Turf-type ryegrasses, while being coarse-leaved, produce nice lawns that are wear-tolerant and do not form thatch.
The popular Kentucky bluegrass does not thrive in our conditions because it weakens and dies over time, is not drought tolerant, and is susceptible to a number of diseases.
If a fungal disease is present in your lawn, a spring and fall application of a fungicide can help control it.
Before purchasing a fungicide, read the label to make sure that it can be used on grass and in the setting you intend to use it. Washington State University-recommended fungicides include Ortho Lawn Disease Control and Scotts Lawn Fungus Control.
Bob Cain is a certified WSU Clallam County Master Gardener.Many helpful gardening publications can be found through the Washington State University Extension online store at https://cru84.cahe.wsu.edu. Some of these publications are available free of charge. For more information on lawns, read “Home Lawns” available for free at http://cru.cahe.wsu.edu/CEPublications/eb0482/eb0482.pdf.
