Custom Search

The Pacific Northwest Heats Up and Magic Plastic Baggies

Portland Here We Come!
Although many of the nation's turf pathologists have been in Chile this week at the International Turfgrass Research meeting, next week many of us turf pathologists will being attending the American Phytopathology Society Annual Meeting in Portland, Oregon.

Call it an unexpected coincidence, but the Pacific Northwest has been hammered with very very high temperatures this last week with Portland hitting 103F and Seattle getting up into the high 90s, likely bringing death and destruction to cool season turf in the area. Usually, courses west of the Cascades see only mild summer heat, but this blast of hot weather will have likely brought a round of anthracnose and maybe even Pythium to the area.

On Saturday, some of us will be touring Portland Golf Course and Waverley Country Club with superintendents Forrest Goodling and John Alexander (respectively). I'm looking forward to seeing what problems the summer heat has brought to the area and to some pathologists geting to see how the guys in Portland grow grass. Thanks to Gordon Kiyokawa (Columbia Edgewater Country Club) for helping us coordinate this outing.

Besides having the chance to see turfgrass culture in the Pacific Northwest, Portland is one of the best coffee and baked good towns in the U.S. One such example is Voodoo Doughnuts, a local shop that dares to put crispy bacon on maple bars and offer other "non-conventional" fried and glazed goodies. I'm looking forward to taking some turf pathologists there next week. Maybe they still have the Pepto-Bismol donut there, well unless the FDA stopped them from offering donuts loaded with what technically qualifies as "pharmacueticals". (Pictured here is one of their "voodoo-doll" donuts - Check 'em out (and other great places like Stumptown Coffee Roasters, Pearl Bakery and Crema) the next time you're in Portland.

Meanwhile, Back in California....
The diagnostic lab here at UCR has been hopping crazy with samples this week. You know things are bad when superintendents are dropping samples off at 6am, have 2-3 drop-in visits from local supers and 2-3 visits from both FedEx and UPS before noon every day of the week!

We're seeing a lot of heat and dorught damage on cool season turf here coming in from around the state. Disease-wise, anthracnose and brown patch are showing up in the lab on greens and fairway/rough samples (respectively). Although we have yet to see gray leaf spot on perennial ryegrass, we've had a fair share of anthracnose coming in on perennial ryegrass samples from collars, fairways and roughs - maybe reflecting both the heat and local water restrictions that might be really puttting a beating on ryegrass in the state.

The forecast for the week is hot in the Valleys and cool on the coasts. Expect to see hot temperature diseases like anthracnose on poa greens in inland locations including Riverside eastern San Diego Co., and the San Joaquin and Sacramento Valleys.

Central California is hot enough at night to have conditions favorable for Pythium, so watch out for that one there. Coastal locations will continue to have dollar spot, rapid blight and brown ring patch pressure.

On the other hand, winter-y conditions will present in Monterey and San Francisco where pink snow mold may be found on cool humid days below 65 degrees.

Isn't it funny that we can have winter and summer diseases active in this state within 60 miles of each other? I continue to be amazed by this state - even as a native born left-coaster.

Amaze Yourself with the Amazing Magic Plastic Bagggie
Although the best way to identify disease problems is sending samples to disease diagnostic labs, the "magic" 1 gallon plastic baggie can be a very useful tool for helping to diagnose a few common summer diseases in a pinch.

Often, fungal mycelia can be seen in the morning in diseased areas, but more often than not - the mycelia will disappear as the canopy begins to dry out. The magic plastic bag (MPB) can help you better identify some of the potential diseases that you may have and also confirm some of the diagnoses you are getting from labs.

Wet your samples down (usually a cup cutter sized plug) and stick them in a plastic bag, seal it and pop it in a warm or room temperature location overnight. The next day, pull out your plugs out and examine them. If you see lots of mycelia growing out of the samples - you know you have active foliar fungal pathogens growing. Depending on what you see - the location and even smell of the mycelia and turf color can help you identifiy some common diseases. (Photo by Scot Dey, Shady Canyon Golf Club)

Mycelia mainly in the foliage, affected leaves look black and greasy, sample smells like fish = Pythium blight

Dense mycelia in the foliage and thatch = brown patch

Dense mycelia in the thatch and soil (or just soil), smells like button mushrooms = fairy ring

Small clusters of mycelia, looks like small cotton balls = dollar spot

Of course - the MPB isn't very good for diseases that don't produce a lot of mycelia, but it's a quick and useful trick for seeing if you have diseases like Pythium blight, brown patch, dollar spot or fairy ring.

Ok - I'll post more tips and tricks using the MPB next week.

Until then, keep and eye out for those diseases and rock on!

Greetings from Chile

Our Summer Field Day was a success and we did actually have dollar spot to show the audience, but nothing else. All of the talks were well received I think. Dr. Chris Williamson spoke about the residual control of black cutworms with Acelepyrn and had a huge crowd for every stop. Dr. John Stier spoke about annual bluegrass management and a new seeding techinque for Kentucky bluegrass that was also a big success. Dr. Stier's graduate student spoke about velvet bentgrass management in the shade. Dr. Doug Soldat's crew did four talks, one on timing of Primo applications, rainwater harvesting and drip irrigation, fall nitrogen fertility and grasses for sustainable landscapes.

The turf pathology team spoke about dollar spot forecasting, which I have mentioned a few times in previous posts. My Ph.D student Chantel Wilson discussed early-season dollar spot programs. This research basically expands on the theory of early-season dollar spot applications to include a summer long program. The goal of the project is to compare costs of conventional dollar spot programs to these early-season programs. So far all of the early-season programs are working just as well as the conventional programs, but we have saved at least one or maybe two fungicide applications by incorporating an early-season fungicide application targeting dollar spot.

My other Ph.D student and technician, Paul Koch, spoke about fungicide programs that target snow mold and dollar spot together. Essentially we make at most four applications a year in the fall and spring and to date we have not seen these treatments break down. However, we have not seen the plots in a week. Again we plan to compare costs of these novel timings to a more conventional fungicide program.

The weather has remained mild in the Midwest during my time in Chile, at least that is what Skybit has told me. The dollar spot forecasting model did kick off and predict another application after 5 days of relative humidity above 70 %. Based on the nighttime temperatures I doubt brown patch or anthracnose has developed in the Upper Midwest at least.

Chile has been fantastic and there were some excellent talks and posters presented at the meetings. This is a beautiful country and I would encourage anyone to think about Chile for a vacation!! Until next week...

Are your greens yellow?

During this time of year, many golf course superintendents report yellowing of creeping bentgrass greens in spots, patches, or irregular areas. While there are a few different diseases and conditions than can cause these symptoms, many assume that “yellow tuft” is to blame. In fact, yellow tuft is not very common in the Southeastern US, and typically only occurs on poorly drained greens or during very wet weather.

A misdiagnosis of yellow tuft can be costly. Few fungicides are labeled for this disease, and those that are have no activity on the other problems that cause yellowing in bentgrass greens. Here’s a description of a few of these “yellow” problems seen on bentgrass greens and recommendations for their management:

Yellow Tuft

Above-ground symptoms of yellow tuft appear in small spots, typically 1 inch in diameter or less. In severe cases, the spots may merge to create irregular areas of yellow turf. Close examination of these spots will reveal that the turf is slightly raised above the canopy. Carefully remove one of these spots from the turf using a knife or ballmark tool, and you will see a massive number of tillers emanating from a single node. This “witch’s broom” symptom is a key characteristic of yellow tuft.

Yellow tuft can cause damage to the turf if left unmanaged. Most of the damage is a result of scalping injury as the infected tillers are pushed upward above the height of cut.

Yellow tuft is caused by a Pythium-like organism called Sclerophthora macrospora. This pathogen infected the crowns and leaf sheaths of the turf. Once established, the pathogen induces excessive production of hormones, which leads causes the excessive tillering.

At this time, the Pythium fungicides mefanoxam and fosetyl-Al are the only fungicides labeled for yellow tuft control. Based on our experience, fosetyl-Al is not very effective, so stick with mefanoxam for preventive or curative applications.

If you have chronic problems with yellow tuft, poor drainage is likely to blame. Taking steps to improve surface or subsurface drainage will eliminate or reduce the problem and save lots of money in fungicides over the long term.

Yellow Spot

In my experience, this is the most common cause of yellow symptoms on bentgrass greens in the Southeast. Symptoms of yellow spot are very similar to yellow tuft, but the spots can be much larger, up to 4 inches in diameter. In addition, the growth habit of the turf is completely normal: it will not be raised above the canopy and no excessive tillering is observed.

Unlike yellow tuft, yellow spot never actually causes damage to the turf. However, due to its aesthetic effect and perceived effect on the consistency of the playing surface, it still warrants management.

We are still not sure what causes yellow spot. We have consistently seen certain types of blue-green algae (cyanobacteria) in the spots, and we theorize that they are producing toxins that induce the yellowing symptom. Other scientists have not been able to establish this same relationship, so the true cause remains unknown.

Nevertheless, we have seen very effective control of yellow spot from applications of chlorothalonil. Applications of 2.7 oz a.i. per 1000 ft2 every 14 days have typically provided good prevention, but higher rates and shorter intervals are needed for curative suppression. In addition, yellow spot tends to be more severe when fertility levels are low and the turf is subjected to frequent drought stress.

Etiolated Tiller Syndrome (ETS)

This is the least well understood of all of the problems that cause yellowing, but has been observed with increasing frequency over the last five years. ETS is easily distinguished from yellow spot and yellow tuft. ETS typically develops in irregular areas, but sometimes it can appear in patches coinciding with bentgrass clones. The key characteristic is that the youngest leaves in affected areas will be etiolated, or elongated and yellow in color. At first the rest of the plant will appear normal, and no increased tillering is evident as with yellow tuft. Some turf decline can occur if turf affected by ETS is subjected to heat or drought stress.

We still have no idea what causes ETS. There are plenty of theories, but no hard facts. Most cases we’ve observed have been associated with combinations of plant growth regulators and various biostimulants containing giberellic acid or cytokinins. Then again, there are a few cases where neither was applied.

If you are having problems with ETS, take a look at what you are applying to the greens. If you are applying plant growth regulators and biostimulants, try deleting one or the other out of your program. This may alleviate or eliminate the problem.

Nitrogen Deficiency

The most frequent cause of yellowing in putting greens is nitrogen deficiency. Typically, nitrogen deficiency appears uniformly across entire putting greens, but sometimes it can have a patchy appearance, especially on older greens, due to the responses of different bentgrass genotypes in the population. Any time you see yellowing, take a look at your recent fertility practices and have a tissue sample analyzed for nutrient content to determine if nitrogen or other nutrients are limiting.

Updates from...Chile?

As I mentioned last week, every four years turfgrass scientists from around the world meet to relay the latest information and research. This year's meeting happens to be located in Santiago, Chile. Before you start complaining about how great it must be to take a "vacation" for work, just know that it is winter here in Chile and the group will be spending most of their time in dark rooms listening to people talk excitedly about turf (does that sound like a vacation?). Having said that, you can bet that I will be enjoying some Chilean wine and decent food while I am hear.

OK, as for the diseases. One of the nice things about being down here with the other pathologists is that I have had the opportunity to ask them what is going on with their regions. I asked a few people from various universities "Is there anything going on in your area that you want to share?" Below are their answers...

John Inguagiato, Ph.D. (University of Connecticut): After a temporary dropoff of dollar spot, the disease has regained momentum and is starting to cause significant damage again. Take-all has been unusually devastating this year due to the cool, wet weather. To help promote recovery John recommends frequent irrigation to the compromised root system. Finally, brown patch has started picking up in the last 10 days and will probably continue due to the expected hot and humid conditions. On a future note, John mentioned that the date of the second UConn Field Day for 2010 will be announced shortly...stay tuned.

Me, (Penn State): From my end, I have seen quite a bit of dollar spot finally taking off in the past week. Type II fairy ring (green rings) has been popping up all over the region as well, but due to the amount of rain the rings are not really developing into Type I (dead circles). Most golf courses have had preventive sprays out for brown patch, but much thought and agonizing has gone into deciding whether applying a Pythium fungicide is necessary. On one hand, we are in late July when the disease is prime for causing trouble. On the other hand, the weather has been anything but typical this year and temperatures have been mild and rain plentiful (at least for most areas). My advice would be to keep an eye on the weather and if night time temperatures look like they are going to increase above 65F in conjunction with extended leaf or thatch wetness (~12 or more hours) then preventive applications should be applied. Pay close attention to watch your "hotspots", since your environmental data is not likely being collected in your courses hottest and most humid locations.

Karl Danneberger (THE Ohio State University): "No, Not really."

Tom Hsiang (University of Guelph, Canada): "I will get back to you."

From the responses above, I guess you could say that from the turf group, blogging is really a goal/hobby of the "younger scientists" (Sorry Tom and Karl, just had to get that jab in there!). That's it from Chile, but keep an eye out for those in the group reporting from the American Phytopathological Society meetings in Portland next week. For me, one "vacation" is enough and I will be heading back to PSU and then off to Pittsburgh and Buffalo for my final rounds of Penn State 2-Year Intern visits!

K-State research update


This week I thought I'd give a photo tour of a few of our turf projects here at K-State. Our turf field day is coming up on August 6th at the JC Pair Horticulture Center in Wichita. The photos show some of the studies here at the main campus.

1) Zoysia sun/shade study

About a month ago we installed a sun/shade study for different zoysiagrass lines. The study was conducted in 2008 and is being repeated this year. Dr. Jack Fry is the lead on this, with PhD student David Okeyo in charge of the data.

The photos show the plots on the day of installation.

We’ll be looking for differences in growth rates/establishment, quality, etc. There are a lot of shady sites out there, and it would be nice to have some options.

2) Bentgrass cultivar trial: management for dollar spot

KSU is working with several universities and other partners in the region to examine dollar spot susceptibility in different cultivars. We have the cultivars at both greens-height and fairway height. M.S. student Cole Thompson is the lead worker on the project here at KSU. With the cool temps, some dollar spot is now appearing in the more susceptible plots. See the image below.

3) Brown patch fungicide trial

We just initiated a new brown patch trial in lawn-height tall fescue. There aren’t too many obvious patch symptoms right now, but brown patch lesions are present and once it gets hot again the patches will likely follow. Graduate students Cole Thompson and Ken Obasa are assisting with this study.

4) Putting greens and DMI PGR effects

In the trial shown below, on A4, we have some treatments that include two DMI fungicides. As you probably know, DMI fungicides can have plant growth regulating (PGR) effects especially in mid summer. In the center you can see an off-color due to PGR effects. Those particular plots are receiving propiconazole and the others are receiving triticonazole which is not showing PGR effects at the moment. In trials at other universities, though, this active ingredient has caused PGR effects. For more info on DMI’s in mid summer, you can look back at Lane’s posting on June 16th.

5) This is our rain-out shelter. There is a rain sensor on the back. When it rains, the shelter slides forward on the rails, preventing rain from landing on the plots. That way we can control how much water is applied to each plot. In the photo you can see the small plots of different colored turf. There are replicated plots of different types of bluegrass. Dr. Dale Bremer and PhD student Jason Lewis are looking at drought tolerance/water use. The rainout shelter, shown here on a sunny day, is getting a real work-out with all the rain this year. Still, there have been opportunities to let the turf dry down and examine differences.

Can herbicides impact diseases?

Next week starts with another International Turfgrass Research Conference. Every four years, turfgrass researchers from across the world gather to discuss the latest information about managing all different types of turf. For my part, I am presenting on two of my favorite interests in turfgrass research...weeds and diseases.

Sometimes research results throw up on you (makes me think of poor old Watson this past weekend...heartbreaker at Turnberry) and present you with some serendipitous findings. This holds true for a variety of fields, but the interactions among plant growth regulators or herbicides and turfgrass diseases in particular can be great.

The first thing that comes to my mind is the reduction of dollar spot from applications of the plant growth regulators Trimmit or Cutless. Due to direct fungistatic effects, these PGRs can result in a reduction in the disease. In our most recent study, the combination of Trimmit + Emerald OR Banner MAXX improved disease control when compared to the fungicide alone and resulted in a savings of a fungicide application over the course of the season. In these economic times, a reduction of a single fairway fungicide application can result in a significant savings.

OK, back to my original point...the conference in Chile.

On Monday (during my next post), I will be giving a presentation on a relatively new herbicide used to control annual bluegrass. Velocity, gaining momentum in the Northeast, can effectively be used to suppress annual bluegrass in bentgrass fairways. While it is labeled for creeping bentgrass, its impact on other bentgrass species (colonial in particular) was unknown. In trials at UConn, we found that applications of the herbicide can result in an increase in brown patch. This may be a particular problem since Velocity is most effective when applied in the middle of summer which is typically the time when brown patch becomes active (To the contrary, Velocity has been shown in other studies to actually reduce dollar spot). Unpublished results also indicate that the increase in disease holds true with tall fescue too.

In the photo above, the untreated plot (center) was virtually disease free while the plot treated with three applications of Velocity (left) was severely infested by the brown patch pathogen.

Although we have not researched it yet, my guess is that fungicides typically used to suppress brown patch would likely minimize any negative effects of the herbicide. With the varying agronomic practices put into place at any one time on a golf course, superintendents should consider how one factor may have unexpected negative (or positive) results.

*Photo credits to Alex Putman, former graduate student at the University of Connecticut

lower temps, lower moisture

We often say, “it isn’t the heat, it’s the humidity.” Indeed, humidity can be a measure of how nasty it feels outside. However, I also like to use dew point. See, hotter air can hold more water. For example, at 90 degrees F, relative humidity of 62% might not sound so bad. But, the dew point is 75. That is, there is so much moisture in the air that the temperature only needs to fall to 75 for condensation to occur. Dew points above 70 are very uncomfortable. Check out “dew point” on wikipedia and you’ll find more details and a better explanation.

On Tuesday evening the dewpoint here in Manhattan, KS, was 77, and I think that is the worst I have ever experienced.

But, the weather has changed and in many areas we are experiencing some relief, with highs in the low/mid 80’s and lows in the upper 50’s (!!) and low 60’s for the next few days.

Brown patch that was highly visible on putting greens on Tuesday and Wednesday is already fading. The image was taken by my colleague, Dr. Rodney St. John, and it’s my favorite photo ever of brown patch in greens-height turf.

With the temperature change, dollar spot that had been suppressed in the heat is now creeping back in.

Earlier in the week I received a couple more samples of Pythium from fairway height perennial ryegrass. The change in temperatures will help reduce disease pressure. In addition the break in temperatures will allow some cultural practices that superintendents might have been holding back on during the hot conditions.

It's gettin' hot in herre ....

Too dry? Too wet? Both can be trouble!
With temperatures hitting the 90s and 100s in many parts of California, summer stress & water management on greens are becoming more and more of an issue. As soil temperatures start to get into the 70s, cool season turfgrass – like creeping bentgrass and annual bluegrass - starts to slow or even shut down physiologically.

(Photo by Bob Vaughey, GCS, TPC Valencia)

Hot dry conditions can damage plants by pushing them past the point of permanent wilt, killing plants in the process. On the other hand, water saturated soils can lead to anaerobic conditions in the rootzone and superheating of the top layer of soil, effectively cooking plants on greens.

A key to summer heat management is the judicious management of irrigation. Creeping bentgrass can tolerate wilt and drought stress to a higher degree than annual bluegrass, while annual bluegrass still requires light frequent irrigation to compensate for the shallow root systems.

An important part of managing both turf species is syringing with light amounts of water during the hottest parts of the day. A light misting on plants during the day can drop canopy temperatures several degrees. On very hot, dry days, syringing can be performed a few times a day between play to maintain canopy temperatures at an acceptable level. However, if you overwater these areas (which is easy when irrigation technicians are aggressively trying to manage hot spots) – you can end up oversaturating the soil profile with water and scalding the plants.

A Shout out for Fairy Ring
Fairy ring and the development of localized dry spots can further complicate water and plant management on turf. Professor Mike Fidanza (Penn State University), one of the nation's experts on fairy ring, will be presenting a short web seminar on fairy ring this next Tuesday, July 21 from 1:00 – 1:40 PM EST (that's 10:00 – 10:40 AM for us West Coasters). Check out this link for more information:

What Else is Going On?
Here in California, summer patch and anthracnose on annual bluegrass are starting to roll into the diagnostic lab at a higher frequency. No great surprise given the high tempertures we're having in many parts of the state. Southern blight is firing on a few locations in southern California, and Pythium is active in the Central Valley as night time temperatures are staying above 68F at night.

All I can say is batten down the hatches, because we're a long way away from the Fall and the summer disease season is only getting started here.

Signing off from the Left Coast until next week!

P.S. - I couldn't think of anything scatalogical for this week's update. Megan, the door's wide open for your Friday update if you so desire.

Much a Do About Nothing

Twas the week before Field Day and not a disease was stirring. Relative humidity levels have plummeted in the Midwest and consequently so has disease activity. The main news throughout the Midwest is the Upper Midwest is extremely dry. Just today the Department of Natural Resources in Wisconsin has enacted a burn ban in Northwest Wisconsin. Fortunately the rest of the Midwest is not as dry. Dr. Derek Settle in Chicago only reported some minor problems with foliar anthracnose on annual bluegrass and reported a dollar spot lull.

Foliar anthracnose is fairly common throughout the Midwest. One superintendent in Madison equates it to a glorified skin rash. The picture that accompanies this post shows the extent of symptoms were are seeing in the Midwest. When symptoms are not severe, it appears that increasing nitrogen, even slight really helps. Dr. Lane Tredway and Dr. Bruce Clarke reported in a recent Golf Course Management article that a tank mixture of Signature and Daconil was quite effective against anthracnose.

If you recall from a few posts ago, I mentioned our efforts with Dr. Damon Smith to develop a dollar spot forecasting model. To date the model has only kicked off twice this year. Partly because the model requires a 5-day average of 70% relative humidity. We have sprayed a series of plots immediately adjacent to our main dollar spot fungicide trial based on the model. Non-treated controls in the main fungicide trial have averaged 65 to 100 spots (largely in part to a week and half of weather in June), yet the forecasting plots remain perfectly clean. I recently spoke with a local golf course superintendent in Madison and he indicated that if he had followed the model he would have saved at least two fungicide applications this year!

These results are promising, but still very preliminary. We still need to see what happens later in the season. Interestingly enough the dollar spot fungus seems to induce symptoms under slightly different environmental conditions during the fall. At least this seems to be the case in Oklahoma. Only time will tell if this is true for the Midwest. Please stay tuned.

Seeing an old friend!

Sorry for the delay and lack of posts this week, but I have been on the road in the Mid-West and haven't been "in touch" with disease issues in the Northeast this week. A nighttime check of the email and a question from a Delaware superintendent sparked my interest in getting a late night post out.

The disease in question is bentgrass dead spot (an old friend of mine). This disease was first observed at the Maryland Diagnostic lab on August 21, 1998. The only reason that I know that date is that I started working in the lab on the 20th and this was one of the first samples that I had seen. That was the beginning of a six and a half year project in which we beat that disease to death and it just about killed me in the process too. is what I told the superintendent dealing with the disease.

Sounds like you are doing exactly what you need to in order to keep it in check. The major problem with BDS is that it DOES NOT recover. My suggestion is to continue with fungicide applications on a 10 day interval (T-methyl, Insignia, Emerald, Dac + one of the aforemetioned...stay away from other strobilurins and bayleton) and start spraying ammonium sulfate with every fungicide application (0.125 lb N/1000). What will happen is that the symptoms will continue to be visible until things start growing actively in Sept/Oct. The fert will finally kick in and aid in recovery and the repeated apps of Amm Sulf will help lower pH and assist in recovery. After the first week of Oct, no fungicide apps are necessary as new infections will be minimal to none and recovery will occur anyway. If you have large spots now, these WILL NOT heal prior to winter and you may consider plugging them out. Any spot smaller than a silver dollar will likely heal before the end of the year. Sorry that I can bring better news, but this is the nature of the beast!

One of the benefits of the down economy is that very few new courses are being constructed and the use of methyl bromide to regrass greens is minimal. These are some of the requirements for dead spot to appear, so this is one of the reasons that this disease rarely makes an appearance these days. As Dr. Dernoeden used to say when samples of yellow tuft came into the lab..."Seeing this disease is like seeing an old friend."

Stress & 'todes

It’s always hard to follow Frank’s posts. I mean, what can I write after he applies “If it’s yellow, let it mellow” to turf disease?

The big concerns lately have been brown patch, foliar Pythium, stress, and nematodes.

While brown patch seems to have decreased somewhat from our surprise late June epidemic, I suspect that it will come surging back in with our forecasts of more heat, humidity, and rain.

Dollar spot has totally disappeared from our research plots. Too hot!

As for foliar Pythium, the rains keep coming, nighttime lows remain high, and the sites with the disease are on high alert. Most have put down one or more applications of a Pythium fungicide and are watching for new activity.

Stress? That is on the plate every week. In some recent samples, waterlogged soils have clearly caused root decline with some secondary Pythium nibbling on the aftermath. We still can’t seem to dry out in some areas.

The photo illustrates a stress problem where greens received a little too much N, got puffy, then scalped. You can see the scalped spots right at the edge where the mower hit the green.

Nematodes in turf are a tricky subject. There was a lot of discussion earlier this week amongst turf pathologists about damage thresholds in nematodes. Damage thresholds are hard to pin down, and the potential damage of a certain population of nematodes varies with the overall amount of stress at the site. Sometimes there is a correlation between turf damage and nematodes; often there is not. Usually there are multiple factors in play.

One nematode that is pretty well documented to cause damage even at low numbers is sting nematode. We picked up sting in a sample a few days ago. I heard Dr. Mike Fidanza (Penn State) joke one time, “If you want to spread news, what are the 3 best ways to do it? 1) Telephone. 2) Telegraph. 3) Tell-a-superintendent.” That is, news travels fast in this industry. After the sting finding, we had a sudden flush of requests for nematode testing because the word had gotten out. Numbers of all plant pathogenic nematodes were pretty low, and no sting nemas were detected anywhere else.

If it's green, what's that mean?

Remember that schoolyard rhyme, "If it's yellow, let it mellow, if it's brown, flush it down"? Well, if it's green, what's that mean? Sometimes in the aftermath of a brown ring (Waitea) patch outbreak on Poa greens, even if you've controlled it with fungicide applications, you can get some strange green patches that form. (Image to the left courtesy of PJ Kaner at Santa Teresa Golf Club in San Jose).

We're attributing this to the pathogen breaking down thatch as it develops on greens, giving a fairy ring like effect in he areas that it's grown through. Often these areas will be softer and spongier than the rest of the green.

Often, when we examine these areas - we'll find lots of Trichoderma (a fungus known for parasitizing other fungi and the active ingredient in some biocontrol products), black sclerotia (next image to the left, courtesty of Larry Stowell - PACE Turf Research Insititute - and other junk fungi colonizing the previously affected area. This can confuse diagnosticians if you send in samples from these areas - and often no 'real' pathogens can be found in these areas.

The key for avoiding this "by product" of brown ring patch infections is to treat early with fungicides when you see symptoms to prevent extensive thatch colonization on greens. You can also bump up your N fertility or even apply some chelated iron in combination with N to mask these symptoms.

Whew! We made it through the 4th of July!
Lane mentioned to me earlier this week in an email that life is good if you make it through the 4th of July without losing any fingers. I can say the same about avoiding disasterous anthracnose outbreaks over the 4th of July on Poa greens out in the West.

Fortunately - no 911 samples came in on Monday morning with anthracnose. There were a number of fairy ring samples, take-all on bentgrass and Bipolaris leaf spot that did show up. These are diseases that typically will cause more damage on heat and drought stressed turf - so it did get hot here in California, but it looks like most of our guys avoided big anthracnose outbreaks on Poa greens.

Also - no gray leaf spot yet!

Hot Inland, Mild on the Coast
The California weather outlook will be basically 70-80s on the coast and 90-100s in Inland Valley s and if you're out in Palm Springs 100-110s.

Expect to see a continuation of dollar spot, Waitea patch and rapid blight in coastal areas. Anthracnose and summer patch will be threats in Inland and Central Valleys. If you're in the desert - bermudagrass should be booming with cool season grass all but disappearing in the summer heat.

Le Tour de France - It's Not Golf, but....
The big race started in Monaco this last Saturday and continues on for another 3500 km for the next three weeks. Lance Armstrong is back after a 4 yr hiatus - maybe to claim an 8th overall victory. There's probably more Americans in the race this year than ever and Team Columbia-HTC, based out of San Luis Obispo, CA is dominating the early flat stages in the race. Lance's team (Astana) took 1st place in the team time trial on Tuesday and Lance sits a mere 0.22 seconds behind the current race leader Fabian Cancellara (Team Saxo-Bank). Friday brings the first of the mountain stages and we'll see how the overall leadership of the race changes as these guys put on their best mountain goat impersonations through the Pyrénées mountains.

Signing off from the left coast until next week.....

Bundled Up in July

A few posts ago I wrote about Pythium blight and brown patch. That was in late June when our highs were consistently in the 90's. We have since moved into a considerable cool down in the Midwest. Highs lately have ranged from the upper 60's to lower 80's with very low relative humidity. Matter of fact last night the low temperature for parts of Northern Wisconsin was 36 F! That's damn cold for the middle of July. The first picture is from Derek Settle of the CDGA and it was taken on July 1 at 1:00pm.

Since the weather has cooled down significantly, so has disease activity. Dollar spot development has significantly slowed in our research plots at the OJ Noer and we have not heard of any major outbreaks anywhere in the Midwest. In previous post I mentioned a dollar spot forecasting model or spray advisory that Damon Smith and I are developing. Well to date the model has only suggested two dollar spot applications, yet most superintendents in our area have applied at least two and some have applied as many as four! Again the model is in its infancy, but is showing real promise.

Brown patch and Pythium blight activity have come to a screeching halt and areas that were damaged seem to be recovering quite well. Currently we have diagnosed take-all patch 5 times from samples submitted from Iowa, Minnesota and Wisconsin. I suspect if the temperature warms up we will see a lot more take-all patch samples. This year was difficult for take-all patch fungicide applications. The Midwest experienced a significant warming in mid-April that drove soil temperatures up into the mid-50's. Yet we did not get above 65 F in many regions until mid to late June. Resdiuals from early fungicide applications may not have lasted until mid to late June, leaving a window of opportunity for the take-all patch fungus to infect. Consequently we are expecting to see a lot more take-all patch come through the lab here at UW.

If take-all patch symptoms do develop on your course, the best thing to do is mark the area somehow and "nurse" it through the summer. Light applications of fertilizer and hand watering should limp those areas through the summer months. Who knows the weather may remain relatively cool for the remainder of the summer.

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.

Check out the smoke ring on July's Centerfold

It just doesn't get any better than this. Just before the 4th of July weekend, brown patch made its appearance in the Northeast. In this case, however, disease activity was more a factor of a unexpected irrigation schedule then the typical hot and humid conditions. Despite moderate conditions as far south as Maryland (I was unable to hear the mycelium crawling around like Megan stated in a previous post), brown patch was active on sites with poor air movement and excessive moisture. While the temperatures are anything but typical for July, certain factors can continue to influence the appearance of these diseases. Brown patch, caused by Rhizoctonia solani, is a foliar blighter and generally does not kill turf. Additionally, the addition of the QoI (strobilurin fungicides) has made controlling this disease relatively easy. For those of you who have increased the use of Tall Fescue in the roughs or introduced colonial bentgrass on select fairways in the Norhteastern US, this may be one that has not caused much concern for you in the past. These two species, however, are highly susceptible and fungicides are often necessary to maintain adequate turf quality.

In addition to brown patch, the usual suspects keep moving along including anthracnose basal rot, dollar spot, fairy ring (generally Type II [those with the green rings]), and a few other unknown problems. In one case (picture right), samples were sent to just about every lab in the Northeast as well as other labs without a clear answer to the problem. After a visit to the course, the problem does appear to be disease related, but no signs of any turf pathogen could be found. This just goes to show you why all of the turf pathologists will be in business for many years to come. Once you get a handle on one disease, another one comes out of no where to make its mark. Examples of this include summer patch in the 80's, gray leaf spot in the 90's, rapid blight and bentgrass dead spot in the late 90's and early 00's, and probably various others too. If I find out more about the mystery disease, I will pass along this info.

OK, I am getting on the road to Saucon Valley to follow Stan Zontek and the rest of the Mid-Atlantic USGA around the course as they prep for the Women's U.S. Open. Follow the practice rounds with me on twitter @johnkaminski.

pythium and brown patch

July 3

Technically it’s a holiday here at K-State. There are a few intrepid graduate students around, and my wheat pathologist colleague stopped in to ponder a few of his own samples, but overall it is very quiet. I’ve been busy sorting through a few turf samples that came in yesterday afternoon, and feeling somewhat relieved that since KSU is closed, no new mail will come in today. I'm sure I'll pay for it with a double whammy next week.

Pythium blight is rare on putting greens in our region, but a case did pop up this week. The assistant superintendent said that the damage seemed to be following mowing patterns. And overall it seemed to have tracked in from the approach and greens surrounds. Mycelium is visible in the image below. They did not observe mycelium on site at the course, but after incubating in the lab overnight it popped right out and I id'd it with the microscope. The turf was very lush and green. I don't have the specific information on their fertilization, but overly high N can make turf more susceptible to this disease and that may have played a role here.

More Pythium blight is showing up in fairway height turf as well, including in one of our research trials as shown in the next photo. There is a slightly low spot in the middle that seemed to get hit. The Pythium area is in the middle-distance.

Brown patch is still on the rampage. I know this is a golf course blog, but I can’t resist posting a photo of my "favorite" brown patch lawn in my neighborhood.

Fireworks, Hot Dogs and Gray Leaf Spot

July 4th weekend usually brings the first major hits of anthracnose on Poa greens and gray leaf spot activity on perennial ryegrass and kikuyugrass fairways and roughs.

We covered anthracnose on Poa greens in California last week. For gray leaf spot in California - we typically start to see hits after July 1 when the minimum daytime relative humidity + maximum daytime temperatures are above 140.

When scouting for gray leaf spot on perennial ryegrass - look for bullseye lesions and fish-hook twisted leaves. On kikuyugrass - you may just see a diffuse blight on leaves (pictured to the left).

Symptoms may develop first in turf at a higher height of cut in roughs and areas that tnd to be shaded and hold leaf moisture longer - so pay attention to those areas first when scouting.

Other than that - it's been a rather quiet week here in the lab. Hot temps in most of the state will likely bring a much more exciting report from us next week.

Happy 4th of July!

Take-all and Summer Patch

Dr. Tredway's post indicated that the temperatures in the Southeast are toasty. Well we were that way last week. The Midwest experienced some extremely warm temperatures, Tuesday was in the 90's, Wednesday was in the upper 80's and Thursday was back in the 90's. Plus nighttime temperatures were hot with high humidity. These conditions reminded me of my days working in Dr. Tredway's program in balmy North Carolina. Last week we had a flush of samples come in to the Turfgrass Diagnostic Clinic at UW-Madison and by the end of the week I was sick at looking at brown patch!

I mentioned last week that the weather in the Midwest never ceases to amaze me, well last week was smoking hot and the high yesterday and today did not get above 65 F. It was actually chilly in July! Last week we saw the development of Pythium blight, brown patch, take-all patch and dollar spot exploded. We even saw some anthracnose on Poa annua at a local Madison golf course. I apologize if I sound a little excited because last year we didn't see squat! Dollar spot would not even show its face in our plots at the OJ Noer.

Back to the issues, take-all patch will likely be diagnosed a lot throughout the Midwest. Many golf course superintendents made applications targeting take-all patch at the appropriate time, but the soil temperatures remained conducive for infection well into June this year. Consequently, we are seeing a lot of "mild" infections. Mild is not a good term, but we do not have another way of describing what we are seeing. The stand symptoms are not very severe nor is the discoloration in the vascular cylinder, but the symptoms are definitely characteristic of take-all patch.

Unfortunately once take-all patch symptoms develop, fungicide applications do not suppress the symptoms. The best approach is to carefully watch the affected areas and hand water them when necessary. A light fertilizer application will also help alleviate the symptoms. Take-all patch is a disease of roots and typically appears in the same place every year, so you likely know the areas that take-all patch occurs. If you do not want to lose grass, then hand watering and lightly fertilizing those areas proactively may help.

This is the time to consider preventative applications for summer patch in Poa annua and Kentucky bluegrass stands. Although the weather turned mild this week, temperatures will probably rebound making conditions favorable for summer patch development. We did see anthracnose develop at a local Madison golf course. This particular course has severely limited nitrogen on putting greens and of course our research area has not received any fungicide applications. Anthracnose has probably not developed on most courses in the Midwest, so preventative applications may still be effective. Dr. Tredway and Dr. Bruce Clarke have found that applications of a tank mixture of Signature and Daconil to be most effective against anthracnose in creeping bentgrass and Poa annua stands. I'm looking forward to what the weather will bring next week, until then enjoy the summer cool-down.
Related Posts with Thumbnails