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!

How's the Spring Dead Spot?

This is probably the most common question I get this time of year as everyone anxiously waits to see how much disease there will be this year or if their preventive fungicide applications worked. Based on our winter weather conditions, with cold temperatures combined with periods of wet and dry weather, I expect the disease to be pretty severe this year and early reports seem to indicate that it's going to be a bad year. We've even had a report of a severe outbreak of the disease on zoysiagrass fairways.

Unfortunately, my travel is limited this time of year due to classes and conferences, so let me ask you: How's the spring dead spot out there? Any particular successes or failures with fungicides? Please post a comment to let us know what you're seeing!

New Granular Fungicides for Turf

Historically, fungicides on granular formulations have never been used frequently on turf. With the exception of late fall snow mold applications and damping off applications to the seedbed, there weren't many situations in which granular fungicides were recommended.

Two things were limiting the usefulness of granular fungicides: a limited selection of products and low-tech carriers that weren't very effective for foliar disease control. As a result, my standard recommendation has always been that if you want good disease control,  you should spray instead of spread. As an example, look at the tall fescue plots to the left that were both treated with triadimefon at the same rate of active ingredient per acre. Triadimefon is not a very effective brown patch fungicide to begin with, but the sprayable formulation (Bayleton) is much more effective that the granular formulation (Fungicide VII).

Things changed quickly, though, and today many more products are available on granular carriers, including recent products like Armada, Disarm, Heritage, and Headway. Several others are currently being tested as experimentals. Furthermore, these new products take advantage of modern granular formulation technology that makes them more effective against foliar diseases by increasing foliar absorption of the active ingredient.

We've evaluated a number of these new granular formulations, mostly against brown patch in tall fescue in a lawn care scenario. I will include a couple of examples here. I would summarize by saying this: these new granulars are more similar to their sprayable counterparts for brown patch control, but generally their efficacy is a erratic and they require more frequent applications. I still think that if you have the capability to spray, it's still better to spray. But these products provide more options to turf managers in situations where spray applications are not possible or practical.

Another possible advantage of a granular formulation is for control of root diseases like summer patch, spring dead spot, fairy ring, take-all patch, etc. To control these diseases most effectively, you obviously want the active ingredient to be in the root zone. With a granular, you can make the application and then water in later at your convenience, rather than having to worry about running the heads right behind the sprayer before it dries on the foliage. While we haven't tested these newer products against root diseases, we always used to see very effective spring dead spot control from granular formulations of Rubigan.

I'd like to hear some comments from our readers on this topic: What are the advantages and disadvantages of these granular formulations in your experience? If you are using these products, how and for what are you using them?

A New Option for Spring Dead Spot and Fairy Ring Control

Earlier this year, the Cleary Chemical Company released a new fungicide called Torque, which contains the DMI fungicide tebuconazole. More recently, Cleary obtained a 2ee label for the use of Torque for fairy ring prevention. Although it is just another DMI, tebuconazole has some unique properties that should make Torque a very useful product for golf course superintendents.

In particular, we've had a lot of questions about the use of Torque for spring dead spot and fairy ring prevention. Although we have not had the opportunity to evaluate Torque against these diseases, we have a lot of experience with a variety of tebuconazole formulations from other companies.

What we can say is this: tebuconazole is very effective for prevention of both fairy ring and spring dead spot. For spring dead spot, we've seen excellent results in bermudagrass fairways and athletic fields from two applications of tebuconazole, 30 days apart, at the high label rate prior to the onset of dormancy. Unlike Rubigan, which only requires one application in many circumstances, we've found that two applications of tebuconazole are necessary to achieve the best spring dead spot control.

Tebuconazole has also provided excellent prevention of fairy ring caused by puffball-type fungi in sand-based putting greens. Following our standard recommendations, two applications of tebuconazole at the recommended rate on a 30 day interval, beginning when soil temperatures consistently exceed 55F, has been a very effective program.

A note of caution for those with ultradwarf bermudagrasses: we've seen severe injury on the ultradwarfs from tebuconazole, and the Torque label says 'Bermudagrasses can be sensitive to Torque Fungicide under certain conditions'. Until we can get a better feel for the safety of Torque on bermudagrass greens, I would stick with older products that are known to be safe.

A Lekker Conference in South Africa

I just returned (as in Friday night) from a week trip to visit golf courses in South Africa and speak to their superintendents (don’t call them greenkeepers) at their Biennial Talking Turf conference. This post is not necessarily about what is happening in terms of diseases at this moment, but a general overview of the grasses and types of problems that they encounter.

One of the primary purposes of heading over to South Africa (aside from giving two talks at the conference) was to attempt to collect dollar spot samples for a large project that Dr. Tredway is working on. Although I did see some “old” dollar spot symptoms on a variety of species, I am not sure how much of this we will be able to isolate from. My initial visits took me to a few golf courses in the Johannesburg region where the primary species were kikuyugrass (image right) and creeping bentgrass in the fairways and putting greens, respectively. I did manage to visit a golf course that had nearly pure Poa annua putting greens.

This brings me to my next thought on the whole visit to South Africa. Aside from the doctors’ warnings prior to my visit (more in a later post), I was pretty unclear as to the types of turf that they grow or the conditions in which they grow them in. Well, it seems to be fairly similar to the United States in terms of diversity with a primary exception being that our seasons are opposite. South Africa is just now entering the autumn/winter months and won’t see spring until around sometime around August/September (if I remember correctly). They do, however, manage similar grass species. The primary putting green species is creeping bentgrass and/or annual bluegrass. There are some courses that do have bermudagrass greens. One commonality among the golf courses is that most seem to be managing kikuyu fairways. I did see one course that had bermudagrass fairways.

As far as diseases, these too were very diverse. During my visits in the Jo’burg region, I only saw some dollar spot and what I believed to be spring dead spot on bermudagrass (although it was appearing in the fall) and kikuyu patch (which again I believe to be spring dead spot). Fairy ring was also prominent on the putting greens of another course. From the superintendents in the Cape Town region, I was informed of putting greens with active anthracnose, dollar spot and even Microdochium patch. Algae (which I attribute to either extreme summer temperatures causing thinning and/or excessive moisture) is also a major problem.

A major disadvantage to the superintendents in the region is the lack of educational resources on a whole. There is no formal turf education in the country and traveling to the states is extremely expensive for a majority of the superintendents. I did meet two individuals who were studying in the Penn State World Campus program and at Elmwood College in Scotland. Otherwise, much of their information comes from the web or books and little positive confirmation of the diseases they have are available. Despite these limitations, I found the superintendents to be very knowledgeable and interested in management strategies.

In trying to keep this to our readable two minute post, I will wrap up by saying thanks to all of the superintendents who showed me around their courses; Sue for inviting me to speak at the conference; Dr. Vargas (aka Elvis shown to the right) for once again creating an entertaining environment and for stirring the pot with his views on resistance management; Marinus for driving us around for the week; Aquatrols, Syngenta and Toro for sponsoring the event; and to everyone else I met. This trip provided me a lot of information for more international posts that I will put up over the next few months. In the meantime, check out the photos from the trip. It was truly the trip of a lifetime.

Oh, and as for “lekker” in the post’s title. This was explained to me as an Afrikaan term that means something that is “better than nice”. Although there was no literal English translation, I took it as meaning “awesome”.

Old Man Winter still apparent, Mother Nature strikes again, a turf mystery, and an interesting rust

On the disease front, large patch of zoysia is still on the rampage and continued rains will not help. Spring dead spot is also apparent in many areas.


Winter damage

I'm hearing more news about winterkill in bermudagrass. People have been noticing it for awhile, but as everything is greening up nicely all around, the damage is becoming even more shocking to the eye.

The next two photos were given to me by my colleague Dr. Jack Fry who recently observed some severe winterkill:

Dr. Fry also snapped some pics of some intense spring dead spot:

And, how about this one?

Below is a photo sent in by Steve Fowler, Superintendent at Hillcrest Golf Course in Coffeyville, KS. Steve knows what happened here to cause this pattern, but for the moment I’ll leave it as a mystery for YOU to ponder and you can post your ideas in the comments box. Hint: this is bermudagrass.

Thanks to Steve for sending this one in. If you blog readers have interesting tales to tell, let us know. Maybe we'll use your case studies, and you can choose to be anonymous or to have your name posted. Of course, you can also post to us at Facebook.

For the rust-geeks out there ... What does this:

… have to do with this: (?)

The top photo is an ornamental tree called Rhamnus caroliniana (common names include Carolina buckthorn and Indian Cherry). The orange growths are one of the life stages (aecial stage) of crown rust, caused by Puccinia coronata. You are all probably familiar with cedar apple rust, which spends part of its life cycle on cedars (junipers) and other parts on apples.

Well, the crown rust pathogen goes back forth from certain grasses (oats, barley, and some kinds of turf) and trees/shrubs in the genus Rhamnus. Common buckthorn, Rhamnus cathartica, is a nasty, invasive shrub. I remember seeing crown rust on buckthorn numerous times up in my home state of Wisconsin.

Anyway, Rhamnus and certain grasses are both hosts of this same fungus. (There are some details about sub-species that I won't get into here). Amazing, huh?

And, the lightning epidemic continues:

I know, it's not turf, but I can't help but share yet another lightning story.

Mother Nature struck again, this time at a house two doors down from mine. There was a colossal boom and flash at about 10:15 pm Tuesday night that caused us to jump out of our chairs.

The next morning, we looked out the window to see a giant pin oak blown to bits down the block.

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!).

No Fun

I hope everyone out there had a great Thanksgiving last week!

Here in California, it's been pretty slow in the Wong Lab. Things are getting pretty cool here (by California standards) and here in the picture, you can see our Tifway-II is pretty much headed into full dormancy in Riverside with our soil temps in the mid-50s. My PhD. student, Chi-Min Chen, and undergrad lab assistant (Erica Serna) are helping me inoculate plots with Ophiosphaerella korrae - one of the causal agents of spring dead spot. I heard the comment of 'this is no fun' a few times this morning which reminded me of a joke my mom told me when I was a kid. It kinda goes something like this:


Q: "What was the name of the first Chinese test-tube baby?"
A: "No-fun Son"
(apologies to the defenders of political correctness out there)

For those who didn't get that maybe this will help:
http://en.wikipedia.org/wiki/Artificial_insemination

The 'maladie de la semaine' continues to be rapid blight on annual bluegrass greens - temperatures in the 60s-80s and a lack of substantial rainfall is allowing salts to continue to accumulate and cause conditions that favor rapid blight.The half-inch of rain that we got in parts of California last week didn't help much in knocking salts & sodium down, e.g. we need substantial or consistent rain to help us flush out the last several months of sodium accumulation on greens.

However, we're expecting some rain and showers, especially in northern and central California starting this weekend /early next week and lasting for a few days. That's great news as far as knocking down salts but bad news as far as Microdochium patch/pink snow mold.With a few days of moisture and daytime temps < 65F, we'll likely see some pinkie firing on annual bluegrass. If you don't already have a preventive fungicide application down, it'd be a good idea to squeeze one out before the showers and rain start in the next few days.

Signing Off from the Left Coast Until Next Week....

Spring Dead Spot Control in Hybrid Bermudagrass

Spring seems like a long way off, but now is the time to prevent your bermudagrass turf from looking like this upon greenup in the spring. Spring dead spot, caused by Ophiosphaerella korrae, can cause severe and long-term damage to bermudagrass on greens, fairways, roughs, athletic fields, and highly maintained landscapes if it is not properly managed.

There are many things that can be done to help reduce spring dead spot development. Probably one of the most effective practices is hollow-tine aerification. In the picture to the right, look how severe the disease is on the recreational area to the right as compared to the soccer field on the left. What's the difference? The soccer field was hollow-tine aerified three times in the previous year, whereas the surrounding areas were not.

In the Eastern United States, most people have good success in controlling spring dead spot with 1 or 2 fungicide applications in the fall. We've found that these applications are most effective when average daily soil temperatures are below 80 degrees and above 60 degrees.

The Midwest is a completely different story, however, as fungicides generally don't work very well against spring dead spot in that part of the country. Some have theorized this is because spring dead spot is actually caused by a different pathogen in the Midwest, where Ophioshpaerella herpotricha is most widespread. However, we've had great success in controlling O. herpotricha with fungicides in North Carolina in the few locations where it is present, so I tend to believe that different soil properties are responsible for the control difficulties observed in certain regions. Just keep in mind that what we find to work best in the Southeast isn't guaranteed to work everywhere.

Over the last 8 years, Rubigan has been the most effective and consistent fungicide for spring dead spot control in our trials. In fairways and athletic fields, we have seen excellent control from 2 applications (30 days apart) at 4 fl oz/1000 ft sq or a single application at 6 fl oz/1000 ft sq. On putting greens, which tend to be more susceptible to spring dead spot, I would recommend a total of 12 fl oz/1000 ft sq applied as either three 4 fl oz applications or two 6 fl oz applications.

Regardless of the program that you select, is critical that all of the applications are made before average daily soil temperatures dip below 60 degrees. This is the point at which bermudagrass plants start to shut down, and after this point the fungicide will not be absorbed and translocated in the plant.

There are other options for spring dead spot control. While Rubigan has been most consistent in our studies across a number of locations, we have also seen good to excellent control from Banner Maxx (2 applications at 4 fl oz), Headway (2 applications at 3 fl oz), and Eagle 20EW (2 applications at 2.4 fl oz) in some studies. Heritage has not provided effective spring dead spot control in our studies.

With any fungicide application for spring dead spot, it is very important that you water the fungicide into the root zone for best results. The pathogen is attacking the roots, rhizomes, and stolons of the bermudagrass plant, so that is where the fungicide needs to be. Most fungicides are absorbed quickly by the foliage, so irrigation must be applied right away before the spray dries on the leaves. On putting greens and fairways, typically 1/8" of irrigation is sufficient, but up to 1/4" may be needed on higher cut areas.

Impact of nitrogen sources on spring dead spot

In a post earlier this spring, I briefly mentioned our recent findings on the impact of nitrogen sources on spring dead spot development in bermudagrass turf. I am preparing to present this research at the upcoming American Phytopathological Society Meetings in Portland, OR and thought I would provide everyone with a sneak peek of our findings.

Most turf managers in the southeast and midwest are all too familiar with spring dead spot. However, in light of the results below, it is important to realize that the disease is caused by three different species: Ophiosphaerella herpotricha, O. korrae, and O. narmari. The most common species in the southeastern US is O. korrae, whereas O. herpotricha is prevalent in the midwestern US. If you are unsure of which species you have, ask your friendly neighborhood turf pathologist to find out which species is most common in your area.

We initiated this research in 2004 to determine how fertilization programs influence these different spring dead spot species. Each plot was inoculated with O. korrae and O. herpotricha in Fall 2004, fertilization treatments were initiated in May 2006, and were continued through 2007 and 2008.

Some of the main findings of this research are as follows:

1. Spring dead spot caused by O. herpotricha was suppressed very effectively in all 3 years by fertilization with ammonium sulfate. Sulfur coated urea provided some control in 2008, and calcium nitrate provided moderate suppression in 2009.
2. Ammonium sulfate had no effect whatsoever on spring dead spot caused by O. korrae. Instead, calcium nitrate provided almost complete control of this species in all 3 years.
3. Fall applications of potassium, dolomitic lime, gypsum, or elemental sulfur had no effect on either spring dead spot pathogen.

What does this mean? We are unsure at this time if the observed spring dead spot suppression is due to changes in soil pH or other nutritional effects. For example, suppression of O. korrae by caclium nitrate may be due to higher soil pH or increased calcium availability. Regardless, if you have struggled with spring dead spot in the past, take a look at the nitrogen source you've been using and consider a change to either calcium nitrate or ammonium sulfate.

Many turf managers apply potassium in the fall, as this has been thought to help reduce spring dead spot development. During the three years of this study, we saw no benefit from fall applications of potassium or other nutrients. It is important to point out, however, that we applied 2.7 lbs K/1000 sq ft from potassium chloride (0-0-60) during the summer in conjunction with our nitrogen applications. Therefore, as long as adequate amounts of potassium are applied during the season, additional fall applications do not appear to influence spring dead spot development.

Kaminski on West Coast?

That's right! I have spent the past week on the west coast visiting my students on their internships (See details here [WARNING...shameless plug!]). During this time I had the opportunity to see some unique management practices and current disease activity in Northern California, Arizona, Utah, and Canada.

One of the most fascinating aspects of traveling to different regions are the various management practices. Having spent a significant amount of time in the mid-Atlantic and Northeast, I am familiar with high disease pressure and intense management practices associated with bentgrass and annual bluegrass.

In the areas visited on this "West Coast Swing", however, disease activity is limited and fungicides are used sparingly. Despite this, there were several diseases and other issues that I had a chance to see on the course. In the San Francisco region, The California Golf Club had just rebuilt the entire course and disease activity was limited to a few small patches of take-all on the new bentgrass greens. The most interesting part of this course is the use of "The Greenway Program", which utilizing various cultural practices to help to minimize Poa populations. (Pictured right: turfgrass intern Niels Dokkuma applies a sulfate mixture to the greens by hand as a component of program). In the northeastern portion of California, a few cases of take-all patch were observed on tees, some old snow mold damage was seen in heavily shaded areas, and a few cases of rust were observed on the Kentucky bluegrass roughs.

In the desert, where disease activity is typically low, fairy ring seemed to be the most common problem on the course. As the bermudagrass fairways were starting to kick in to high gear, some remnants of spring dead spot were also hanging around. Although I didn't get a chance to see any on the trip, the most surprising disease in the region were a few select cases of dollar spot. This is the first time that I have heard of dollar spot showing up in the desert! Just another reason why the establishment of a regional dollar spot research project is a good idea.

Just south of Salt Lake City, Red Ledges Golf Course was getting ready to officially open its doors. While I am sure there was disease SOMEWHERE on the course, I did not see ANY disease during a 5 hour tour around the course with my student. The major concerns there dealt with wrapping up construction projects and dealing with animal damage to the select areas of from the elk and voles (pictured right).

My final stop is here in Panorama, British Columbia. Disease pressure here is basically limited to winter pathogens including the snow molds. While diseases are not a concern, major issues include the potential for winter kill. Over the past winter, snow fall in the region was limited during the winter months. While the snow generally acts as a buffer and keeps the turf protected, the greens in many Canadian regions were exposed to -30 temperatures for a long period of time. In fact, much of the damage occurred during a period in April when melting snow on the greens rapidly froze as nighttime temps rapidly dropped. To add to the problems, the slow start to spring/summer in the region is making recovery efforts more difficult. Weather is finally getting to be suitable for growing grass and recovery should be apparent soon.

Thanks to Frank for allowing me to post on his day and to all of the superintendents and students for showing me around the courses!

Update from Kansas

Hello,

It's Friday, it's Friday, and a beautiful day it is here in Kansas. Lucky me, I have some field work scheduled for the day.

The spring rains are continuing. Large patch of zoysia is popping up all over, including in our research plots (see image). While pulling some samples of large patch in zoysia at a golf course, I also found some rust (see image).

Now that the bermudagrass is greener, symptoms of spring dead spot are becoming more apparent.

Though dollar spot is not yet active at our research facility, I heard from a superintendent that they had dollar spot active on most greens.

Here in Kansas, it's time to be thinking about summer patch in sites that have a history of this disease. For more information, you can check out this website:

http://www.plantpath.ksu.edu/DesktopModules/ViewDocument.aspx?DocumentID=986

It focuses on Kentucky bluegrass but information is relevant to other grasses as well.

Got Brown Ring Patch?

Well, if you have those bright yellow rings on annual or rough bluegrass and its between 65 and 90 degrees F, there's a good chance you have some brown ring patch (aka Waitea patch) brewing this spring.

Like John mentioned earlier this week, symptoms can look a lot like yellow patch or even the early stages of southern blight or fairy ring. A definitive diagnosis should be made - but bright yellow rings with a slightly green ring inside of that are good symptoms of brown ring patch on Poa greens. Here's a classic photo of the disease taken a while ago by Pat Gradoville at Palos Verdes Golf Club.

There's a downloadable PDF on my website that covers the symptoms, biology and control

http://www.turfpathology.ucr.edu/Downloads/Management_BRP.pdf

In a nutshell - at least two fungicide applications are often needed for complete control. Some fungicides like Headway or Endorse appear to give quick knock down of the disease, while others like Trinity or ProStar apear to take longer to act but can give very good residual control.

Other than that - rapid blight continues to hit salt affected Poa greens in the west (more on that next week) and spring dead spot symptoms are popping up on bermudagrass as we are in full transition to warm season turf growing conditions here and some guys are ony now seeing how thin (or dead) their bermuda bases are. Check out Lane's timely post on SDS for tips and tricks for dealing with SDS recovery.

Spring Dead Spot: What can I do now?

Spring has sprung in the southeastern US, and severe cases of spring dead spot have been reported throughout the region. The relatively severe winter is likely to blame, as cold temperatures tend to bring out spring dead spot symptoms.

The frustrating thing about spring dead spot is that the damage is done and the disease cannot be controlled once the symptoms appear. However, there are several things that can be done NOW in preparation for next year:

1. Consider converting severely affected areas to a cold-tolerant bermudagrass variety. Varieties of bermudagrass that have been bred for cold-tolerance, like Patriot, Yukon, and Tifsport, are affected by spring dead spot less severely. They still get the disease, but patches are generally smaller and recovery is quicker. This simple solution can save a lot of time and money in the long term.

2. Map severely affected areas for fall fungicide applications. Spring dead spot fungicides, like Rubigan, are very expensive. You can save a lot of money and avoid unnecessary fungicide use by only treating the affected areas.

3. Avoid the use of DNA herbicides for annual grass control. Some crabgrass herbicides reduce bermudagrass root growth and can slow recovery from spring dead spot. Use a pre-emergence herbicide like oxadiazon, which does not have this effect.

4. Aerify and/or spike severely affected areas every two weeks. Breaking up the layer of dead turf and thatch will help the bermudagrass to spread into the patch more quickly.

5. Choose your nitrogen carefully. The type of nitrogen you apply can have a major effect on spring dead spot development. We have traditionally recommended ammonium sulfate to suppress spring dead spot, but our recent research is providing some interesting results. After 4 years of applications, ammonium sulfate is only suppressing spring dead spot caused by Ophiosphaerella herpotricha and is having NO EFFECT on O. korrae. Calcium nitrate, on the other hand, is doing an excellent job of controlling spring dead spot caused by O. korrae, but is having no effect on O. herpotricha. Stay tuned for updates on this research.

patch-a-rama in Kansas

Hello from Kansas

The warm-season grasses are greening up. Spring rains and temps in the 60's and 70's are triggering the development of large patch in zoysiagrass (see photo). I have not seen or heard of symptoms of spring dead spot yet in bermudagrass but I'm sure that will be coming soon.

As for the cool-season grasses, a superintendent in south central KS reported some yellow patch (cool-season brown patch) in the putting greens. Late April is fairly late, but with our unusually cool, wet weather I'm not surprised that this disease has popped up. Another person reported some powdery mildew on tall fescue in the Kansas City area.

Spring Dead Spot