Why Is My Lawn Dying?

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Large patch disease

Rapidly expanding circles of dying turf are the main symptom of large patch.

PEST ALERT UPDATE FROM NCSU TURFILES

You know it’s officially spring in North Carolina when there are giant patches of brown grass in bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass. These giant patches of brown grass are better known as large patch, caused by the fungus Rhizoctonia solani, and if you’ve ever had an outbreak of this disease, you now know why the disease was coined large patch.

What you may not know however, is what your control options are this time of year. You shouldn’t worry too much if you have this disease on bermudagrass. Bermudagrass tends to grow out of the damage once the temperatures are consistently warmer and the daylight longer.

As for our other warm-season friends, damage tends to be most severe on centipedegrass and recovery may take all summer in extreme cases. Unfortunately, there isn’t much you can do to make for a magical recovery. We rarely recommend fungicides for large patch in the spring of the year, however in worst case scenarios, a fungicide application might help prevent the disease from spreading further. Fungicide applications are best when they are applied preventatively in the fall. If you choose to spray a fungicide this spring, don’t expect a miracle to happen overnight. Also, remember that recovery will be even slower and tougher if you’ve applied a root pruning herbicide as your pre-emerge for summer weeds (these include many of the pre-emergent herbicides found in crab grass preventers and weed and feed products) .

Large patch disease

Individual patches are surrounded by a red or yellow halo.

In most cases, the best thing is to stay the course with management practices that will encourage each type of grass to do well (see the link below for tips on warm season grass maintenance). In severe cases, treating damaged areas like a new establishment with light and frequent fertilizer and water inputs may help encourage faster lateral spread. This doesn’t mean you should apply more fertilizer, just smaller doses more often. Applying too much fertilizer will make the disease worse this fall!

Finally, be sure to map the affected areas now while they are clearly visible. You will save yourself some money this fall by spot treating these areas instead of having to make a whole property application, since the disease tends to reappear in the same areas.

For more information about large patch, click here.

For more information about warm-season grass maintenance, click here.

Original post: http://www.turfpathology.org/Pages/blog_entry.aspx?PID=4515402440792257690

Written By

Photo of Lee ButlerLee ButlerExtension Coordinator (919) 513-3878 elbutler@ncsu.eduEntomology and Plant Pathology - NC State University
Updated on May 13, 2013
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