Question: I was told that my lawn has red thread. Can you tell me what that is and how to treat it?
Answer: Red thread syndrome actually refers to two separate diseases, pink patch disease and red thread disease, that may display very similar symptoms in your lawn. Red thread disease is the more common of the two and is often more severe than pink patch in susceptible grass varieties. Red thread is caused by the fungus Laetisaria fuciformis and pink patch is caused by the fungus Limonomyces roseipellis.
Slow-growing turf that is under stress is more susceptible to red thread. It may appear first in areas where there are nitrogen deficiencies. Lawns infected with red thread and pink patch will have small to large, circular to irregular shaped, water-soaked patches that die rapidly. Some smaller patches may eventually coalesce into one or more larger patches. Red thread disease will have pink to pale red sclerotia or fungal thread-like growths that resemble antlers and can extend ¼-inch or more beyond the tip of the grass blades. They are more easily observed in the early morning dew or anytime moisture is present.
Most homeowners ask for the recommended fungicide for their lawn’s problems. However, if the disease is present at a level noticed by a homeowner, it is usually too late for a fungicide to be effective. In order for a fungicide to be effective, it must have been applied preventatively. This entails re-applications every two months from May through September. Fungicides are costly and require special equipment for an effective application to prevent disease.
To manage your lawn for maximum disease control, follow good cultural practices. When establishing or renovating an existing lawn, select a grass mixture that is specific to your site’s conditions, such as shade, full sun or high traffic. Using a variety that is not site-specific will lead to weak, thin grass. Most lawns in New Jersey are comprised of cool season grasses: Kentucky bluegrass, perennial ryegrass, tall fescues and fine fescues. Each of these varieties has different tolerances to hot summers and diseases. Perennial ryegrass is the most susceptible turf grass species to red thread. Fine fescues vary in susceptibility with creeping red fescue being the most susceptible and hard fescues having greater resistance to this disease. In other grasses it can be found but is usually less severe.
You will need a soil test on the area in question to determine pH and nutrient levels. The key is to maintain adequate and balanced soil fertility levels in order to optimize plant health. Irrigate deeply in the early morning hours and as infrequently as possible, but often enough to prevent drought stress. A healthy lawn can recover more rapidly from periodic red thread disease outbreaks. Keep your mower blades sharp and avoid mowing wet grass. Also addressing thatch layers that exceed ½- to ¾-inch thickness and soil compaction in late summer and early fall will help reduce the ability for red thread to survive.
For more information on lawn diseases you can contact your local extension office. Atlantic County residents can contact the Master Gardener Helpline at 609-625-0056. Cape May County Residents can call 609-465-5115, ext.3607.
Events: Atlantic County Master Gardeners will be available to answer gardening questions and take samples for plant identification or diagnoses throughout the county this summer. You can find us at the Brigantine Green Fest on Aug. 24 and Hammonton Green Day Festival, Sept. 21. We will also be available at Atlantic County Library branches throughout the county evenings in the fall. Please check with your local library for a schedule.
Interested in our Junior Master Gardener Program? We will have an information session 6 p.m. Sept. 16 at the Rutgers Cooperative Extension Office in Mays Landing. Call 609-625-0056 and ask for Brittany Rigg or Kendrin Dyitt for more information.
Do you have a gardening-related question you would like answered here? Please forward your questions to Belinda Chester, Master Gardener Program Coordinator, Rutgers Cooperative Extension Office, 6260 Old Harding Highway, Mays Landing, NJ 08330. You can also submit questions at Rutgers-atlantic.org/garden or email them to firstname.lastname@example.org; please include “garden question” in the subject line.