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The Woes of Warm-Season Turf in Spring

May 12, 2011
by Lee Butler

The two most common diseases of warm-season turfgrasses are having their way this year in the Piedmont and Eastern NC.  They are large patch and spring dead spot. Multiple reports from the field and positive samples in the clinic have confirmed this. 

Large patch is causing severe damage on centipedegrass, zoysiagrass, and St. Augustinegrass right now.  It is also causing some damage on bermudagrass, however you shouldn't worry if it's on your bermuda because it will grow out of the damage once conditions are better, i.e. hotter.

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 DNA type of herbicide as your pre-emerge for summer weeds.

Spring dead spot is causing severe damage to bermudagrass and zoysiagrass.  As with large patch, it is too late for a fungicide application.  You will need to wait until this fall.  Once again, recovery will be very slow if you've applied a DNA type of herbicide.

In most cases, the best thing is to stay the course with management practices that will encourage each type of grass to do well. 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 diseases 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. (http://www.turffiles.ncsu.edu/diseases/large-patch)

For more information about spring dead spot, click here. (http://www.turffiles.ncsu.edu/diseases/spring-dead-spot)

For more information about warm-season grass maintenance, click here. (http://www.turffiles.ncsu.edu/Maintenance_Calendars.aspx#000024)

large patch turfgrass disease
Large Patch

 

Spring Deadspot turfgrass disease
Spring Dead Spot