Severe Brown Patch-Fungus Issue With Fescue Lawn

Asked January 3, 2017, 10:34 AM EST

Hi. I have a problem and questions about fungus in fescue lawns.... What WAS a perfect green complete fescue lawn last spring in Huntingtown was attacked by fungus...I think “brown patch”... mid-late summer 2016….A lot of patchy brown grass first…then lost the brown grass to bare dirt spots all over the place (50 yards wide by 20 yards long)….and now have the muddy dirt spots in winter with a lot of green slime (fungus?) in the open dirt areas. It’s pretty nasty looking stuff, like in the bottom of a dirty fish aquarium. Still have some areas of patchy fescue….but it’s thin. Used to be the envy of the neighborhood. So far, we have had a few days below 30F and it has not killed the fungus. It turns a bit brown on very cold days but as soon as it warms back to 40F ...its green wet slime again. Resilient stuff. And really nasty looking stuff!!! :( Per normal, I over-seeded / fertilized (10-20-10) in the early fall and a lot of seed did not germinate. It’s still sitting there in the yard. I assume this was due to the presence of the fungus, which I did not treat for. What did germinate did not do too well…first, it took a long time to start up, much of what did germinate is gone now…back to dirt. I would want to repair this by over-seed in the late winter-early spring… as early as i can to fill in the bare spots killed last summer. But, if I reseed without removing the fungus, I doubt it'll be effective, right? I probably used too much fertilizer in the early fall. I understand that is a contributing factor. Had the PH checked a year ago in this general area, as I recall it was “OK”, like 7.0 or thereabouts…they did not recommend any Lime needed at that time. I probably watered it too much in 2016, as we had a new sprinkler system installed….my new toy and I used it too much…  Lesson learned. So, do I need a fungicide...or will a good snow pack (none as of yet) kill the fungus for good? If no, when can i apply Fungicide? Can It be applied in January and be effective? Shall I wait till late winter-early spring? How long would I wait to re-seed in spring after fungicide treatment? I read about a product called Fusillade II. Seems to be pretty good. I guess I am wondering if putting down a fungicide now...when it's 25-40F will be effective. It looks to me like the fungus is still alive (green). Will a good snow pack kill it? The area of the yard with the issues is ALWAYS wet. 24/7. Humidity in the morning and it just does not dry out even on sunny days. Too much shade, not enough direct sun? If it rains, it’s of course even more wet. Sloppy. By the way, this problem is only in the back yard...the front is really nice, never took a hit. Less shade, stays drier. For whatever reason, does not have this issue. Sorry for the random thoughts…but I think that covers it. Suggestions? I am close to your office, thus I can send pix or bring samples.

Calvert County Maryland

3 Responses

The present problem is not the fungus, it's the high moisture levels. Fescue cannot grow in soggy soil. A fungicide is not necessary. The green algae you see is a symptom, not a cause.

In poorly drained or compacted areas, a black or greenish crust may form on bare soil in areas of thin turf. This black or greenish substance is algae growth, which can be more severe in compacted soils or shaded areas. Algae may have a slimy appearance when the soil is wet. It becomes crusty as the soil dries.

To control algae growth, eliminate or reduce the conditions that encourage it to flourish. Increase drainage by redirection of water from downspouts and aerate compacted areas. Add soil or grade to eliminate low areas from the lawn. Increase sunlight in shaded areas by removing overhanging trees or branches, if possible. Select shade tolerant grass varieties in areas where shade cannot be reduced. Fertilize and overseed according to University recommendations to establish a thicker stand of turf.

Fall is the best time to reseed, though you may need to seed in spring (much of this new growth usually dies over the summer.)

It's good that you realize over-fertilizing can lead to fungal disease. Also, Maryland has a law regulating how much and when fertilizer can be applied to lawns which was put in place to protect the Chesapeake Bay. Here is a helpful chart for fertilizing effectively in Maryland:

In our website's Library, there are many terrific articles on successful lawn care. We recommend you check them out. Here is a particularly comprehensive one:


Hi There, and thanks for the great reply. Algae makes sense... as I have a pool I can certainly relate!!! LOL. And yes, I slipped on it recently in the yard. My only option it appears will be aeration in the spring, then overseeding, then cutting back on watering. I don't want the grass to be so patchy for a long time till next fall. My dogs love the mud. My sprinklers are closed and I would need to wait to aerate till I mark the location of the heads in the spring. Actually, the majority of the fescue area in th eback yard under discussion here is in open sunlight and on a gently sloping hill for most of the day. And far from the gutters are not the issue. Maybe 20% of the area is in afternoon shade. I think the drainage is pretty good for the majority of the problem area due to the slope, except for a smaller area close to the house. I'm thinking I just ran the darn new sprinkler toy too too much last year. The front yard which looks great is on a similar slope and probaly has slightly more that is possaibly a mitigating factor for too much shade being the problem. One new question: What is a good "shade tolerant" fescue. I think I used good old Kentucky 31 this recent fall. Mark

In general, turf type tall fescue grows best in full sun to part shade. Kentucky 31 was recommended in the past but new improved cultivars have deeper color, finer blade texture, and higher tiller densities which allows the grass to fill in. Consider if you have at least 4 hours of direct sun. See the attached publication

Fine fescues are comprised of creeping red fescue, hard fescue, chewings fescue, and sheep fescue and are recommended for shady conditions. They do not perform well under frequent foot traffic, soil needs to be well drained, will not tolerate wet conditions or high rates of nitrogen fertilizer. Turf should not be mowed when hot and/or dry. See above publication for recommendations. This does not sound like a good combination if you have dogs. Here is a good article on lawn care and dogs. Look at step 5.
Whatever you decide, you will have to keep the dogs off the turf until it establishes itself. Sounds like you may have to seed in the spring and fall this year. If you have dogs, you may find that you need to overseed in the fall as a general practice.
Also, do not water on a schedule. Water as needed. See our website for more information on watering lawns