Spring dead spot of zoysiagrass

Spring dead spot of bermudagrass

After a cold winter throughout much of the Southeast, damage from spring dead spot is particularly severe on bermudagrass. Scenes like this one are all too common when visiting golf courses in North Carolina right now.

We're also seeing an unusually high number of spring dead spot outbreaks on zoysiagrasses across the southeastern US. Samples, photos, and reports of spring dead spot on zoysiagrass fairways, tees, lawns, and landscapes have been rolling in all spring.

Spring dead spot of zoysiagrass?

Yes, this is not a new thing. Spring dead spot was first documented in zoysiagrass by Green et al. in 1993 as part of the zoysia patch complex, which turned out to be mostly large patch and a little bit of spring dead spot. The Color Atlas of Turfgrass Diseases by Tani and Beard also lists spring dead spot as a disease of zoysiagrasses in Japan. 

In North Carolina, we've seen spring dead spot on zoysiagrass every year since 2002 and documented that it is caused by Ophiosphaerella korrae, the same species that infects bermudagrass in this part of the country.

Spring dead spot of 'El Toro' zoysiagrass

Overall, zoysiagrass seems to be more resistant or tolerant to spring dead spot compared to bermudagrass. The patches are typically smaller and not as widespread. Given the superior cold tolerance of zoysiagrass, this makes sense. The problem is that zoysiagrass is even slower to recover from spring dead spot than bermudagrass. Although the symptoms may not be as severe, they can linger for extended periods of time.

Not all zoysiagrass varieties seem to be susceptible to spring dead spot. In Kansas the disease was observed on 'Meyer'. In North Carolina, most cases have been observed on Zoysia japonica varieties like 'El Toro' and 'Empire'. 

Spring dead spot of 'Diamond' zoysiagrass

This year is a little different in that we're seeing spring dead spot on more varieties. Most notably, we've confirmed the disease on golf course fairways and tees established with the Zoysia matrella cultivar 'Diamond'. To our knowledge this is the first confirmation of spring dead spot occurring on Zoyisa matrella.

Spring dead spot management on zoysiagrass is identical to that on bermudagrass. We've seen very good results from preventive application of fenarimol (Rubigan) in the fall. Regular cultivation during the summer also helps to reduce spring dead spot development and speeds up the recovery process. We're continuing to research the effects of nitrogen sources and other fertilization practices on spring dead spot development, but I don't have time to open that can of worms this week. Stay tuned for details on that in next week's post!

Why They Call it the Transition Zone

Spring dead spot of bermudagrass

As the old joke goes, "In the transition zone, we can grow all of the turfgrasses, we just can't grow any of them well".

The last year has been an excellent demonstration of this fact. Spring 2010 brought major problems with winter-kill in the warm-season grasses across much of the southeast. Everyone will remember the summer of 2010 as the year when record heat caused widespread failure of creeping bentgrass putting greens. 

Large patch of bermudagrass

The spring of 2011 hasn't been much kinder. Spring dead spot is particularly severe on bermudagrass this spring, and I've heard several reports of control failures from preventive fungicide applications. We've seen an unusual number of cases of spring dead spot on zoysiagrass as well (more on that next week).

Large patch (aka zoysia patch, aka brown patch, aka large brown patch....did I miss any? Seriously, can't we all just call it large patch?) is raging on all of the warm-season grasses as well. This spring is the first time I've seen large patch cause significant damage to bermudagrass in the Raleigh area. Zoysiagrass, St. Augustinegrass, and centipedegrass are affected very severely as well.

Many people struggle with these diseases of warm-season grasses because they have to be treated long before the symptoms express themselves. It is easy to forget about spring dead spot and large patch in the fall when everything is looking good. 

In addition, the economic downturn has led to severe budget cuts at many facilities, and the poor warm-season grasses are usually the ones that are left to fend for themselves without fungicide protection.

Over the next few weeks, I'll be writing in more detail about spring dead spot and large patch in the warm-season grasses. We'll cover things you can do now and during the growing season to help manage these diseases and how to prepare for preventive fungicide applications this fall. Stay tuned!

First app of 2011

First spray of the year

On Monday I drove to one of our zoysia large patch study areas at a golf course about 90 minutes away. I had been kind of dreading it. I just have NOT been feeling ready for the field season.

But, it was a beautiful day and I realized that I'm pretty lucky that my job allows me to work outside (even though some of those days can get pretty long). The superintendent, assistant superintendent, and staff at this course have been fantastic trial hosts over the past few years.

The large patch was not "hot" yet, but near the study area there was a "shadow" of a patch that was there before (last year), and will probably become active again soon, maybe after this week's rains.

This is a small trial with 6 treatments and an untreated control, and I can share results later.

"Shadow patch"


Active patches like this, with orangey margins, should be coming soon:




"Landscape, with Tidy Cats Bucket and Truck" (my artwork for the day)




Bermudagrass is continuing to green up, too.

Here's our KSU football practice field (bermudagrass) on April 6:


April 16:


I would have taken another today, but it was pretty gloomy and rainy.


Fertility Legislation

I came across an article about fertilizer legislation in Virginia, New Jersey, and Washington:
.
http://www.turfmagazine.com/article-6727.aspx
.
.
Any comments from folks in those areas?
.
.
.
.

Spring has Sprung!

Well it looks like ol' Jack Frost is slowly shedding his coat in favor of a pair of shades and t-shirts. Spring has been slow in coming, but with 80's on the horizon in the next couple of days it looks like everything is off to the races here. From a disease/stress perspective what does that mean to you in the Southeast? Well, for the warm-season grasses (like bermuda), we should be able to start seeing how bad the winter actually was by starting to see some greening up of the tissue.

Now is the time to start looking at the stolons and stems, to see if color is returning like you see in the image to the right. If the tissue seems dead and brown, it might be time to think about ordering up some sod and/or sprigs. Another disease issue that will start be the impact the winter had on the development of spring dead spot. In Tennessee, we haven't greened up enough yet to see the circular symptoms of the disease (see left image), but with the warm weather that is ahead, it is only a matter of time.

Finally, for those of you managing zoysiagrass, large patch (see image below), caused by Rhizoctonia, will begin to rear its ugly head again. This disease can also attack bermudagrass, but the damage is not usually severe enough to warrant fungicide application (see image far below- that's a large patch!) credit: Adam Nichols, Virginia Tech)

The question of how effective spring applications of fungicides are for large patch is a good one. I don't think we have enough data to conclusively answer the question. Hopefully, you made a few applications in the fall, as that is the best time to apply preventatively.However, if you have an outbreak of large patch that is actively growing, fungicide applications might be warranted to at least reduce the spread of the disease.

Our junior-year turfgrass students are setting off on their internships for the summer, so I will be posting much more frequently now that teaching is on hiatus for awhile. So I am off to start looking for large patch in my trials, but the difference is I get excited when I have a bunch of it, and it is uniformly distributed over my plots!

Stay tuned for the next couple of weeks as we look at what spring has for cool-season diseases/stresses next week, and the following week, what we need to start thinking about for summer (which will be here before we know it!).

Snow in the Northeast, Dormant turf in Dallas

This week, I had the opportunity to visit a couple of golf courses in the Dallas region. While I was touring these courses, the entire Northeast was getting pummeled by one of the largest snow storms of the century (thank goodness for the #snOMG posts on twitter, otherwise I wouldn't have been able to keep up with it).

Anyway, since the entire Northeast is currently under anywhere from a few inches to a foot or more of snow, I thought that I would give a special post for those in the Dallas area.  My visits took me to the Dallas National Golf Club and Colonial Country Club.  These 2 courses provided a unique opportunity to see a mix of both warm-season fairways/roughs and cool-season putting greens.  Recent cold temperatures shut down the growth of the bermudagrass (Colonial Country Club) and zoysiagrass (Dallas National) fairways and slowed the growth of the bentgrass putting greens.  The greens were in excellent condition at both clubs and disease issues were few and far between.

During the season, diseases that can often be found on the course include fairy ring, spring dead spot, and large patch.  In fact, there was a few remaining patches of large patch on the zoysia in the practice facility where fungicides are used on a limited basis.  Control of the patch diseases is being managed with fall and spring fungicide applications.  As you can imagine, the major issues at the courses are seen during the heat of the summer when severe stress is put on the bentgrass putting greens.  I hope to get back sometime to see the course in these conditions...a pathologists dream!

Other issues which I don't typically get to deal with included the development of algae in some of the bunkers and the management of warm-season encroachment into the bentgrass putting greens.  I hope to be able to pass along some information from our GCSAA algae grant which is currently in progress.  Although the project's goal is to manage algae on putting green turf, I am interested to see if some of our findings could translate to the bunker sand as well.

The visit with Scott Ebers and Brannon Goodrich was great and I appreciate their hospitality in showing me around the course.  Both courses were in excellent condition and unique.  Colonial with its rich history and long-standing relationship with the PGA and Dallas National with its unique zoysiagrass fairways and spectacular views are must a must see for anyone interested in golf OR interested in growing bentgrass in some of the most difficult environments.  To me, this would be like growing Poa greens in the mid-Atlantic...not an easy task during the intense summer months.

Despite being in Texas, we were impacted by the storm as all flights from Dallas to Philadelphia were canceled on Sunday and here I sit in the airport on Monday writing a new post. I just hope that we make the earlier flight (currently on standby), because if we don't we will not get home until ~11PM. I did post an image above of Dallas National taken from my phone, but I will have to wait until I get home to upload photos from the course.

Large patch is brewing in the warm-season grasses

With cool, wet weather setting in across much of the southeast, now is the time to initiate a preventive fungicide program for large patch on the warm-season grasses. Zoysiagrass, centipedegrass, and St. Augustinegrass are most prone to this disease; large patch rarely causes significant damage to bermudagrass turf. Not all turf needs to be treated with fungicides to control large patch, but areas that have sustained severe damage in the past should be sprayed on a preventive basis.

One great advantage of the warm-season grasses is that they are fairly resistant to diseases; in most parts of the southeast, we only need to worry about one or two diseases on these grasses. Spring dead spot is a major problem on bermudagrass, and large patch can cause severe problems on all the others - zoysiagrass, centipedegrass, and St. Augustinegrass.

One problem with large patch is that it comes at a time when the warm-season grasses are shutting down for the winter or greening-up in the early spring. As a result, the potential for recovery once symptoms appear is slim to none. Once an outbreak occurs, you're probably going to be looking at those symptoms until April or May when the turf really starts growing again.

The other problem with large patch is that the appearance of symptoms is very unpredictable. Sometimes they appear in late summer, other times during the fall, and in many cases no symptoms are observed in the spring. So how are you supposed to prevent the symptoms if you don't know when they are going to appear?

The answer is easy - don't time your fungicide applications based on when symptoms have appeared in the past. Instead, you should time applications based on when the pathogen is active. As it turns out, we know that the large patch pathogen becomes active when soil temperatures consistently dip below 70 degrees at the 1 to 2 inch depth. In other words, NOW IS THE TIME TO START PREVENTIVE PROGRAMS FOR LARGE PATCH IN MANY AREAS!

There has been much confusion over the name of this disease, and as a result, very few fungicides are specifically for 'large patch'. Some labels still refer to the disease as 'brown patch', whereas others call it 'zoysia patch'. Since they are all caused by Rhizoctonia solani, any fungicide that has one of these diseases on the label can be used for large patch control.

In some cases, one well-timed fungicide application in the fall can provide season long control of large patch. However, in severely affected sites, where disease pressure is high, repeated applications are often necessary. Two applications in the fall, 4 to 6 weeks apart, and one application in the spring when the turf is nearing full green-up is the ideal program. If three applications are not possible financially, the fall applications are probably more important than the spring application.

Strong brown patch fungicides like Heritage (0.4 oz of 50WG or 2 fl oz of TL), Insignia (0.9 oz) and ProStar (2.2 oz) are very effective for large patch control. Some of the DMI fungicides, Bayleton (1 oz) in particular, have performed very well also. Recent trials have also shown that Headway (3 fl oz), a pre-mix of Heritage and Banner, is a very effective large patch fungicide.

For more information about large patch management with fungicides and cultural practices, please refer to our Large Patch Disease Profile on TurfFiles.