One of our technicians was able to get a photo of Red Thread and Brown Patch together in the wild. Which of these do you think is the bigger threat to your lawn?
Although the Red Thread looks mare damaging, it’s actually the Brown Patch, though in this picture it looks pretty minor. Here’s what it can turn into—quickly.
Blog post: Brown Patch Disease in Fescue Lawns
Diagnostically, the red thread can be identified by tan/brown areas with red fungal threads that spread in patches through the grass. The affected area will have a pinkish cast, and look matted. Fuzzy pink mycelium may also be present. Brown patch does not form visible external fungal growths, just dead tan patches.
While both are warm weather problems, red thread is more active when temperatures are moderate (around 70F) while brown patch really gets bad when temperatures are even warmer (80’s and above)
Brown patch will kill the crown and roots of the grass it infects, quickly causing extensive damage to your lawn that may require seeding to repair. Red thread looks icky, but does not kill the plant and recovery is quick once disease pressure is reduced.
Both funguses thrive when humidity is high and leaves remain wet overnight, which is why we always recommend that any irrigation of the lawn be done in the early morning, so it can dry before nightfall. Of course, late afternoon and evening rain is out of your control, so even if you do water properly it’s a good idea to keep an eye out for both diseases in warm weather.
Proper cultural conditions (proper mowing height, adequate but not excessive fertilization, good air movement and proper irrigation for humidity control, and healthy, biologically active soil) will create a healthy lawn and reduce the occurrence of both diseases.
While brown patch should be treated quickly as soon as it’s noticed, red thread is mostly a cosmetic problem and will often resolve with no treatment, particularly if any existing cultural problems are addressed.