Heat Wave Forecasted for Next Week

We have seen relatively few disease issues in the TDL the past month or so. Throughout Upper Midwest temperatures have been warm, but we have also been quite dry. However the forecast for next week is very different. Highs for next week will been in the low to mid-ninties, more importantly night time temperatures will exceed 72 for most of next week. I included a 7-day forecast from NBC 15 here in Madison, but areas west and south of us will likely experience even hotter temperatures. I know that doesn't compare with the excruciating heat experienced by those in the Southeast and Central US, but the forecast is significant for the Upper Midwest. Especially considering that many courses have substantial Poa annua populations.

IF YOU haven't done so already, this weekend or early next week is a great time to protect your plants against brown patch and Pythium blight. Environmental conditions next week will be ripe for these two diseases. Moreover, anthracnose, dollar spot, summer patch and leaf spot could also flare up depending on where you are with fungicide applications. I mention leaf spot because we have been dealing with a Bipolaris leaf spot in the Midwest for two or three years that does not respond well to applications of iprodione. This disease also remains active throughout the summer months and has been problematic primarily for older golf courses. The disease tends to be more severe on certain clones of older creeping bentgrass fairways causing a "splotchy" reddish appearance to fairways. It does not manifest into distinct symptom. An image of typical stand symptoms is below.

Last year we initiated a fungicide trial at a course in Wisconsin to investigate chemical control options and found that Heritage TL, Insignia and a tank mixture of Chipco 26GT and Daconil Ultrex suppressed symptoms when compared to the non-treated control. Chipco 26GT by itself did not suppress the symptoms, indicating that Daconil Ultrex was more effective in controlling this disease. Note that I use the word suppress we have not been able to prevent the development of this disease, only suppress the symptoms. Here is the report from last year's trial. This has been a difficult disease to work with because it only seems to affect certain clones. Thus it took some time to figure out how to rate it.

Some other things to consider for next week: limit mowing by alternating mowing and rolling, skip clean-up passes, raise the mowing height and absolutely avoid applications of DMI fungicides to putting greens.

Beautiful Weather, Finally?

This spring has been one of the coolest and cloudiest on record. Just last week I was in Stevens Point, WI and soil temperatures barely reached 60 F. Still prime time for take-all patch and fairy ring preventative applications. To be honest not much is happening around the Upper Midwest. We have had reports of brown ring patch, but thats about it. Derek Settle at the CDGA has reported brown ring patch and a bit of dollar spot. We have seen and heard of multiple cases of creeping bentgrass turning red this spring. We think it is a combination of proxy/primo or trimmit + DMI fungicides for take-all/fairy ring + cool temperatures. The symptoms are typically seen on older leaves and we cannot find spores of any kind in the samples. An image of the symptoms we are seeing is above, sorry the image does not show the symptoms very well. If anyone has any thoughts on this matter they would be welcomed and appreciated!

Finally I thought I would reiterate a former post Lane wrote. He presented a succinct description of diseases that typically affect creeping bentgrass and annual bluegrass putting greens. There has been concern in the Midwest with the substantial amounts of rainfall we have received that Pythium root rot could be a problem. Yes Pythium root rot could occur at anytime as long as the soils are saturated, but considering creeping bentgrass and annual bluegrass grow well during the spring I rarely think of Pythium root rot as an issue. This brings me to another point Lane made in a previous post, is Pythium root rot a disease. I think it is a disease because we would not see symptoms characteristic of root rot if the pathogens were not present. Keep in mind though once/if summer rolls in and we continue to receive significant rainfall, then we might see issues with this disease. I am not saying that fungicides are not warranted, but I do think it is unlikely that Pythium root rot would/did occur this spring in the Midwest.

Recap of 2010-2011 Snow Mold Trials

It seems funny to talk about snow mold on April 26th, but thanks to mother nature there isn't much else to talk about in the Midwest. We have experienced a very cool, wet spring so far this year. Just last week northern areas of Wisconsin received 7 to 9 inches of snow! We were very lucky that the dates we picked for our snow mold field days were nice, well at least the weather was nice at two of the locations. We have five locations for our snow mold trials: Brainerd, MN, Les Bolstad Golf Course in St. Paul, MN, Grant Park Golf Course in Milwaukee, WI, Sentryworld Golf Course in Stevens Point, WI and Wawonowin Golf Club in Champion, MI. We travel to these different locations in order to test fungicides against as many snow mold pathogens as possible.

For this post I thought I would summarize the a portion of the results from Sentryworld. The picture at the upper right hand portion of this post was taken by Dr. Derek Settle at the CDGA and shows the level of disease at this trial. Although the non-treated controls averaged 74%, this is misleading because a single control somehow escaped with only 22% disease. The primary pathogen observed at this location was Typhula ishikariensis. Once again we observed that mixtures of fungicides that incorporate multiple modes of action worked very well. The graph below depicts a sample of results from this trial. There were 90 entries and the remaining treatments as well as the other sites can be accessed through our webpage soon. Mixtures with Torque (tebuconazole) worked very well, especially a mixture of Torque and Affirm (polyoxin-D). An interesting new fungicide is Velista, which is a carboximide fungicide (other members of this family are Prostar and Emerald). It does have activity against snow mold fungicides on its own, but not enough to provide acceptable control. When Velista was mixed with a DMI (in the figure Banner MAXX is presented) and chlorothalonil, these mixtures performed well.

Instrata at 9.3 oz performed well in our trials as it has for many years. Concert provided significant reductions in snow mold even when applied by itself at the 8.5 fl oz rate. This year we had a number of Civitas mixtures in our trials and they performed well. The product applied alone will not control snow mold, but when applied as a tank mix component results were quite good. Finally, Interface continued to show good efficacy against snow molds. Interface by itself did reduce snow mold severity, but not to a level that we consider acceptable (<5%). Yet, adding Daconil dropped snow mold severity to acceptable levels.

Now that the season is finally getting going, I will start posting once a week again. We have initiated a number of very interesting research projects that I will post about this year as well as updates on what we see in the TDL, so stay tuned!

Observations from Wisconsin and How Dr. Soldat Would Manage Potassium on Cool-Season Turf

Hello again from the Midwest. Its be a while since I have posted and its because old man winter will not relinquish his grip on us. We have only had the opportunity to rate one of our 5 snow mold sites. Last week three of our sites received another 5 to 12 inches of snow. Where the snow has melted, I am assuming winter kill and breakthrough were minimal. My only metric to assess this is my phone has been eerily quiet. So since I do not have much to report on with respect diseases, I am privileged to post comments from Dr. Doug Soldat on managing potassium on cool-season turf. I think this fits well into the discuss John started concerning Poa management.

Turf Diseases Blog: How I’d Manage Potassium on Cool-Season Turf

Doug Soldat

Dept. of Soil Science

University of Wisconsin-Madison

Over the last several years as the turfgrass nutrient and water specialist at the University of Wisconsin-Madison, I’ve slowly been developing my philosophy of potassium management based on my research, the scientific literature, theory and observation. I teach my view point every fall to a group of students who are too green to be shocked, but when I revealed my philosophy to a group of workshop attendees at the Canadian International Turfgrass Conference in Vancouver in March, it was clear that my recommendations were a major reversal from what they’ve been taught. Similarly, you may have heard Dr. Rossi (Cornell) and Dr. Gaussoin (Nebraska) debate the importance of potassium at GIS and elsewhere. So, I thought I’d throw my hat into the ring; and because disease plays a major role in my management philosophy, I’d thought I share my thoughts with this community. A much more detailed defense of the ideas below will be published in the Grass Roots in June (official publication of the Wisconsin GCSA). I’d be happy to email you a copy of that when it’s available, just let me know djsoldat@wisc.edu. So, without further ado, here’s how I’d manage potassium if I were a Golf Course Superintendent:

Fairways:
I’d apply potassium only according to soil test levels. I’d use modern interpretations of optimum (i.e. 50-100 ppm, depending on soil test) instead of the more common values of 200-400 ppm. I expect even the 50-100 ppm levels will be adjusted downward as more soil test calibration studies are conducted, but for now 50-100 is fine.

If/when potassium dips below that soil test threshold, I’d make a 1 lb/M application in May. I’d re-test the soil in fall to determine if another application is warranted the following spring. Why May? The evidence for potassium improving drought tolerance is much more convincing that the evidence that potassium increases winter hardiness (although, I believe the opposite is true for warm season grasses). Also, Dave Moody and Frank Rossi’s work at Cornell University has clearly linked increased potassium in the leaf to increased severity of gray snow mold (and pink to a lesser extent). Similarly, Dr. Ebdon et al. (2006 – Mass.) reported more severe gray snow mold at higher K application rates on ryegrass. In summary: there is only weak evidence that K increases cold tolerance for cool season-grasses, strong evidence that it increases snow mold, decent evidence that it improves drought tolerance. I’d go with May.

If my fairways were something other than sand, I’d apply muriate of potash (0-0-60), if they were sandy, I’d consider using a polymer coated K source or spoon feeding in 0.25 lb/M increments if practical. Most non-sand soils have a high enough cation exchange capacity to retain a 1 lb/M application of potassium. Sandy soils may need some help provided by the polymer coating or spoon feeding approach.

Greens:
Assuming most greens are sand-based, either from construction or years of topdressing, I’d spoon feed potassium along with nitrogen in the ratio of 2 parts nitrogen to 1 part potassium beginning in May and ending in August (but continuing with N after that). I like to fertilize my research greens about every other week with 0.2 lbs N/M as urea, so that’d put me at 0.1 lbs K₂O/M per application or about 1.0 lbs/M for the season. I feel this is a very conservative approach which replaces the potassium removed by clippings. But as the research continues to unfold, I can imagine that my management philosophy for greens may evolve to look more like my fairway program. That said, if I were an actual superintendent, I’d leave the research to the researchers and use this conservative but research-based approach.

Why stop in August? Same philosophy as above, the benefits of potassium as a drought stress nutrient are much more convincing that the cold tolerance argument and we have seen that high tissue K increases snow mold pressure. Also, research by Woods et al. (2006 – New York) and Johnson et al. (2003 - Utah) has shown clearly that high soil potassium levels in sand based greens are always substantially reduced by spring, presumably by the snow melt leaching the potassium out of the root zone. Therefore, a large application to a sand root zone in fall will do two things: increase your susceptibility to gray snow mold, and 2) leach out of the root zone, becoming unavailable in spring resulting in a complete waste of time and resources.

One Final Note:
All this talk recently about fostering an environment that favors bent over Poa makes me wonder why a superintendent with such a mindset would want to apply any potassium at all. Poa is obviously more susceptible to heat, drought, and cold stress than bentgrass, so why apply a nutrient that supposedly increases tolerance to those things? Yet, I’ve not heard mention of potassium management as a key strategy. I’m not saying it should be -- I tend to think we’ve overestimated the role of potassium in stress tolerance —it’s just interesting that potassium has been left out of the discussion so far.

Superintendents Encouraged to take Anthracnose Survey!

TAKE THE SURVEY

As you may remember a relatively large group of researchers from various universities across the country have been actively working on research related to the management of anthracnose basal rot of annual bluegrass. The project started about 5 years ago and was kicked off by gathering information from about 400 superintendents and turf professionals to figure out what was happening in the field and what was lacking the way of research-based recommendations. Well we have come to the end of the first phase of the project and are hoping to 1) gather information about your current management strategies and 2) utilize this information to fine tune our research priorities over the next 5-year phase of the project.

Thanks to the help of the Golf Course Superintendent's Association, we have launched our follow up survey that many of you requested to be a part of. Well now's your chance. Please help us in our goal of finding better solutions to your anthracnose problems by filling out the online survey.

TAKE THE SURVEY

To Spray or Not to Spray

It is really nice to experience a warm-up in Mid-February, but we know that it is a likely a cruel trick from mother nature. NBC 15 in Madison just said that Monday could yield 5 to 10 inches of snow, if all the expected precipitation is snow. Yet, today temperatures exceeded 40 degrees in Southern Wisconsin and is expected to exceed 50 degrees tomorrow! Its funny that I get excited about 50 degrees, when I was in North Carolina I considered that cold. As the warm-up continues, the snow will be melting and gray snow mold and Microdochium patch may show their ugly heads. If fungicides were applied last fall, then I would not expect too much damage. However some areas south of I-80 may not have made preventative applications. I know many down in Missouri, Arkansas, and maybe even Kansas did not make preventative applications. Based on the duration of snow cover in those areas, gray snow mold will most likely not be a problem. Microdochium patch however may be a problem.

The question arises, should I spray when the snow melts? To determine if an application is warranted there are two things to consider: 1) Is the fungus causing new infections? 2) Is the ground saturated? When the snow melts Microdochium patch symptoms maybe apparent and severe, but if environmental conditions are not conducive the pathogen will not continue to spread. Microdochium patch will continue to develop when temperatures remain below 68F with high humidity, intense cloud cover, or both. Symptoms immediately after snow melt usually have the "classic look" with a pink or orange tint. An image of these symptoms are at the upper right hand side of this post. If environmental conditions are conducive for Microdochium patch development in the absence of snow, symptoms will have a water-soaked appearance with center gradually turning a light brown. An image of those symptoms are below. If there are any questions about the activity of the fungus send a sample to a diagnostic lab.

Another factor to consider is how saturated the soil is. Applications of any material to saturated ground should be avoided entirely. Failing to do so could result in loss of the material to runoff. Another consideration is running equipment over saturated ground will likely do more damage than the fungus will.

If conditions become conducive for Microdochium patch development, there are fungicides that will halt its development. Fungicides with the active ingredients iprodione, vincozolin, thiophanate methyl, trifloxystrobin, azoxystrobin, pyraclostrobin, fludioxonil, and chlorothalonil are effective against Microdochium patch. Normally it is hard to beat the dicarboximides and thiophanate methyl for Microdochium patch control, but there are other options that maybe more relevant in your area. Chlorothalonil does not perform all that well by itself, but it is a good tank mix partner with any of these other products.

On another note, after receiving much ridicule from Dr. Kennelly and the Packer Nation that surrounds me about the tragic loss the Bears were handed by the Packers, I am looking forward to baseball Spring training. Like I say every year, as all Cubs fans do, this is the year to break the Billy Goat curse!

One last recap of 2010

from www.techdigest.tv

For those of you that have come to know me on this site, you probably also know that I am nuts. This is the kind of crap that keeps me busy during my insomnia in the middle of the night. Although this information is probably useful for web developers to make sure that the site shows up similarly across different platforms, I don't really have that much interest in the information. BUT, I do like the way that Google Analytics allows us to visualize the information. Without further adieu, here are the top browsers used to surf the Turf Disease Blog!

#7-10 Blackberry Phones
#6 Opera
#5 Mozilla Compatible Agent
#4 Chrome
#3 Safari
#2 Firefox (my personal choice)
#1 Internet Explorer

Check out the use during the year in this video!

Top 10 Visits by Country

As mentioned earlier in the week, we had visitors from 130 different countries or territories. While the majority by a long shot are from the United States, here is a round up of the top 10 visits by country in 2010:

#1 United States

#2 Canada 

#3 United Kingdom

#4 Thailand 

#5 Australia

#6 Japan

#7 Turkey

#8 Ireland

#9 Germany 

#10 South Korea

Top 5 Blog Posts of 2010

There's no doubt about it, 2010 was a tough year for golf course superintendents. Here's a look back and what was most important or relevant to you from our site last year.

#1 Bacterial wilt of bentgrass...
This was the posting of a letter from Dr. Mitkowski of the University of Rhode Island in which he talks about his recent finding of bacterial wilt in bentgrass. Definitely a hot (and controversial) topic in 2010.

#2 Summer fungicide programs for cool-season putting greens
There is no doubt that those growing bentgrass in the Southeast United States had their hands full this summer. In this post, Dr. Tredway shares some early (June) information about planning your summer fungicide programs with special mention to specific diseases including: Pythium blight, Pythium root rot, Pythium root dysfunction, anthracnose, fairy ring, nematodes and brown patch.

#3 Bacterial Wilt, no not? That is the question.
Dr. Wong posts a September blog about recent reports of dying annual bluegrass and creeping bentgrass greens. He links to a few other posts and suggests that although bacterial wilt may be the cause, getting conditions required for the disease in Southern California would be "like coordinating a trainwreck."

#4 Beware of the DMI fungicides
 In another post by Dr. Tredway, he warns of the potential issues with using the DMI fungicides during the summer months. This post was on June 16, so hopefully you heeded his warning and backed off of these products during the intense summer we had. If you didn't then you likely played right into the hands of Pat O'Brien and went through or are planning a bermudagrass conversion!

#5 The Turf Diseases Image Gallery
Did you even know that the Turf Diseases blog had an image gallery for the various common diseases that you may see at your golf course. Hosted on flickr and utilizing images from Dr. Tredway and me, the gallery serves as a visual tool to help diagnose your turf diseases problems or even as a photo collection for you to build powerpoint presentations for your club (giving full credit to the photographers of course).

Top 10 Referrers of 2010

While we would love to think that all of you have us booked marked or saved as your browser's homepage, we definitely understand and appreciate the fact that many of you find us by clicking on links from referring sites. We want to recognize those sites for providing content or links that got your to us. So to steal the thunder from David Letterman, here is our:



 Why they drove visitors to our site-list.

No. 10: It was either you or Voodoo Donuts.

(University of California Riverside's Turf Pathology Site)

No. 9: Wait, we did what?

(Kansas State Turf)

No. 8: สิ่งที่เราควรทำอย่างไร

(Asian Turfgrass Center Blog)

No. 7: I guess the words "disease" and "porn" are closely related.
(Google images)

No. 6: Because we don't update during our insomnia.
(Golf Course Industry) 

No. 5: Even we're tired of listening to Kaminski.

(Penn State Turfgrass)

No. 4: @turfdiseases needed more followers.
(Twitter)

No. 3: We ran out of money to produce more Frank Rossi videos.
(TurfNet)

No. 2: This is what we do, dumbass.
(Google)

...and the number 1 reason our referrers said they drove traffic to our site...

No. 1: Because we're trying to drive the old people from our own site.
(Facebook)

Turf Diseases 2011 Recap

Now that 2010 season is finally over, it is time for us here at Turf Diseases to recap some of the highlights from the past year. This week I will bring you some "Top Lists" for the website. I am happy to say that we have branched out beyond just what happens here in the United States. To the right you can see that although our focus audience is here in the states, we are reached 130 countries/territories in 2010.


Over 57,000 visitors (over 24,000 unique visitors) frequented the site last year (figure below). It was clear that there were a few hot spots in terms of times to visit. Needless to say it is obvious that things were tough in July and August and this caused many of you to I assume check out what was happening around your region and with other golf course superintendents as well.

The 2010 Top 10 List...
Some other things of note coming up this week include my version of Letterman's Top 10 for the following categories:

Top referrers to the website in 2010 (some of you made the list!)
Top Posts of 2010 (based on your visits)
Top Visits by Country (see how your country stacks up)

Special Turf Nerd Post (you could probably do without seeing this one)

What the future holds...

The 2010 season marked the first full year of our existence and we couldn't be more happy with the results. In fact, the success of this little blog site has inspired me to expand in 2011 with the hopes of something big by 2012 (sponsors beware). If you have any ideas on how we can improve the site (big or small), please feel free to share it with us in the comments below!

Honor (boscalid + pyraclostrobin)

Honor is a relatively new fungicide from BASF that contains the active ingredients boscalid and pyraclostrobin. Boscalid is the active ingredient in the excellent dollar spot fungicide Emerald and pyraclostrobin is the active ingredient in Insignia. Like Insignia, Honor will also be marketed under the umbrella of Intrinsic brand fungicides from BASF. If you have not heard of this, it basically states that pyraclostrobin may provide some additional plant health benefits aside from disease control. If you recall, John posted a blurb about our meeting at Farmlinks in October where we shown all the data behind the Intrinsic label. Although the data is a bit sketchy, there does appear to be some benefit to the plant. Before I go any further remember that these are fungicides and should only be used for disease control!

Disease Control

Honor is an excellent fungicide for broad spectrum disease control because it takes advantage of the dollar spot activity of boscalid and the brown patch and anthracnose activity of pyraclostrobin. Other diseases listed on the label are gray leaf spot, fairy ring, take-all patch and pink snow mold just to name a few. Therefore it could fit into a fungicide program for tees and greens at almost anytime of the year. However, I think it fits best during July or August when brown patch and anthracnose are likely to develop in the Midwest. Below are a few graphs highlighting the strengths of Honor against dollar spot. If you want to see how Honor's efficacy against anthracnose and brown patch compares to other fungicides, click on the diseases and you will see reports from Dr. Bruce Clarke at Rutgers University.

Curatively Honor (boscalid in particular) is slow to reduce the dollar spot epidemic, but overtime provides the best suppression. Preventatively Honor controls dollar spot well, but only provides acceptable control at the 1.1 oz rate under the pressure we experienced this year.

Summary

Honor is an excellent product especially for dollar spot and brown patch. I think the best fit for this particular product is during mid summer when dollar spot is still active and brown patch and anthracnose are just starting to get going. Plus pyraclostrobin also has activity against Pythium blight under lower pressures. Essentially this product could almost fit anywhere in a fungicide program in the Midwest.

Instrata (Chlorothalonil + Propiconazole + Fludioxonil)

Instrata is another fungicide that combines different active ingredients into a single product. Instrata has chlorothalonil (Daconil and many others), propiconazole (Banner MAXX and others) and fludioxonil (Medallion). Instrata quickly became the gold standard for snow mold control in northern climates like the Upper Midwest. Interestedly the formulation of this product combined suspended particles with a microemulsion that Syngenta calls a suspomicroemulsion. I really don't know what that means for golf course superintendents, but you have to admit it sounds cool! All kidding aside, we typically suggest that active ingredients should be mixed in order to achieve acceptable snow mold control. With Instrata you have three active ingredients that when combined do provided excellent snow mold control. Chlorothalonil is a contact fungicide that has activity on all three snow mold pathogens (Microdochium nivale, Typhula incarnata and Typhula ishikariensis), but is strongest on M. nivale and T. incarnata. Propiconazole is a DMI fungicide, which are known to have excellent activity on T. ishikariensis and fludioxonil seems to have activity on all three snow mold pathogens too.

For those who manage golf courses in areas that receive intense snow cover will likely experience all three snow mold pathogens at one time or another. I think the reason Instrata is a successful fungicide for snow mold control is golf course superintendents don't have to worry about predicting the weather because all the product works on all three snow mold pathogens. With respect to efficacy of Instrata, I have posted a few figures highlighting how well this product works. We do see breakthrough at our site in the UP, which has intense snow mold pressure. Yet, for the last two years we observed that 70 % of the products break down under that pressure. Even under that pressure, a single application of Instrata keeps disease severity levels between 15 and 40 %. Anyone that experiences such snow mold pressure should make two applications for snow mold and we observed that two applications of Instrata at 5.5 oz worked better than a single late application of Instrata at 11 oz at our UP site. For most golf course superintendents however, the 9.3 oz rate will work beautifully! A word of caution about the product, do not skimp on the rate in areas of high snow mold pressure. We have observed that reducing the rate to 5.5 oz in some environments may result in significant failure.

In summary, Instrata is an excellent combination fungicide for controlling snow mold diseases. It also has activity on other diseases too, which is obvious based on the active ingredients in the product. Instrata is an excellent choice for putting greens and tees and if the budget allows high value approaches and maybe even fairways. If you are interested in this product and have not used it before check out the label and Syngenta's website for more information.

Theme Week: "New" Fungicide Reviews

As a way to increase our postings during the winter months and keep providing relevant information to golf course superintendents, the Turf Disease Blog has decided to do a series of "Theme" weeks in which each blogger tackles a topic within the theme.  Thanks to Dr. Tredway for coming up with the idea.

Our first theme is going to focus on reviews of individual fungicides that are relatively new to the market. Each blogger has simply been told what fungicide to review and what day to post. Other than that, there are no restrictions or guidelines as to the material presented.  I suspect that you will see a little data and some decent summaries of the strengths, weaknesses and potential issues with each fungicide.

"New" Fungicide Reviews*

Monday 11/15: Interface

Tuesday 11/16: Heritage G (and other granular fungicides)

Wednesday 11/17: Instrata

Thursday 11/18: Endorse/Affirm

Friday 11/19: Reserve

Monday 11/22: Concert

Tuesday 11/23: Civitas

Wednesday 11/24: Honor

Thursday: 11/25: Renown (posted 11/28)

Friday 11/26: Trinity/Triton

*Reviews of individual fungicides by authors of this blog do not endorse, promote, or in any way recommend the use of specific products. Reviews are based on public information, personal experience or company input. If you have questions or comments about the individual reviews, we encourage you to share your thoughts in the comments section of the individual blog post. Your question or comment may be something that provides valuable information to others reading the blog. Authors will do their best to respond to questions/comments in a timely fashion!

If you are interested in learning more about some of the fungicides that are now available, check back over the next two weeks.  Yes, I said TWO WEEKS...the idea was so good and there were so many fungicides that we decided to have everyone tackle two products and post through the week of Thanksgiving...sorry Megan!

Your Input Requested!

Do you have an idea for an upcoming "Theme Week"? If so, then leave us a comment below OR on the Facebook page. We can't promise we will get to them all, but we will do our best to address your concerns during the winter months while disease pressure is low!

Things to Consider Post PCNB Stop Sale Order

Hello again, its been a few weeks since I have posted anything. Except for the news about PCNB, the fall has been exceptional in the Midwest. Temperatures have been very conducive for golf, almost too conducive. I wonder if those who lost turf this summer had any difficulty recovering because of too much traffic during the fall season. Samples completely halted at the Turfgrass Diagnostic Lab around October 1st, mainly because we were fairly dry. The only disease that proliferated during the fall was rust, even some golf course superintendents called about massive amounts of rust in the roughs.

For those that had to select an alternative to PCNB there are a few things to consider for next year. First, one of the beauties of PCNB was its long residual control of Microdochium patch. Thus if Microdochium patch is observed after melt, than a follow-up fungicide application maybe warranted. Our research has shown that the fungicides iprodione and chlorothalonil only provide about 30 to 40 days of Microdochium patch control under winter conditions. Interesting enough we did not see extended control when comparing plots covered in snow versus those plots that were kept uncovered. The image above shows the length of control we observed with chlorothalonil. In other words, do not blame your snow mold fungicide mixture if new Microdochium patch infection centers develop during the spring immediately following melt.

The other thing to keep in mind is the issue with PCNB has not been resolved, at least not to my knowledge. Basically it would be wise to think about budgeting for snow mold without using PCNB as an option. That way you are prepared if the stop sale is not lifted. There are a number of options that I have already covered in previous posts, but feel free to contact us if you want to discuss other options for next year.

Most of the bloggers attended in the Agronomy meetings in Long Beach, California last week. I love these meetings because of the breadth of information presented. One of my favorite talks from the meetings, besides my own students', was given by one of Dr. Frank Rossi's students David Moody. He has determined that potassium applications in the fall may make turf more susceptible to snow mold damage. They established a very elaborate growth chamber experiment to test this hypothesis, but they stumbled upon this observed causally in the field. Basically they think the excess potassium stimulates the plant to shuttle potassium, citrate and malate into the vacuole in order to maintain osmotic potential. In turn this shift in osmotic potential slows down the production of carbon skeletons and energy, which are essential to plant defense. I believe this was the first or second year of David's research and I will be interested to follow his results and progress.

One of the highlights of the meeting was an outside meeting to discuss a proposal for a Multi-State Regional Project on Dollar spot research. This is a formal process that will allow all those who participate to meet once a year to discuss dollar spot research. Originally this idea was spearheaded by Dr. Mike Boehm at Ohio State University, but the reins was passed to Lane upon Dr. Boehm's promotion into upper administration at Ohio State. The beauty of this meeting was hearing what everyone was doing and realizing that very few turf programs overlap with respect to dollar spot research. This project has a five year term, so maybe in five years we will have a better handle on the biology of dollar spot!

Stay tuned next week as we start a series of discussions on the newer fungicides released in the past couple years!

Cool Temperatures Bring a Sigh of Relief!

Temperatures in the Midwest are finally cooling down. This week has been a godsend as I heard from a superintendent this afternoon. Yes temperatures are going to rise again this weekend, but the nighttime temperatures are supposed to remain below 70 degrees. I agree with John that this is the time to start overseeding, fertilizing and maybe even aerifying to bring the greens back to life before winter. However, I do not think this is the time to start bringing the mowing heights back down and starting on paclobutrazol programs. I tend to be very conservative and I think this week is an ideal time to allow the plant to grow under the least stress possible.

This week’s cooler, dry weather has shut down most of the diseases we have dealt with this summer. I don't know this for certain for every location in the Midwest, but I do know that my phone was very quiet the last few days. We still are getting samples of Poa annua crapping out either from heat stress or summer patch or a combination of both. This was an exceptionally difficult summer for golf course superintendents. Most the turf loss this year was due to heavy rains in June and July coupled with high day and nighttime temperatures. Soil temperatures in many locations I visited exceeded 95F, which is not a good growing environment for any cool-season grass to say the least.

The major lesson I learned this summer was the importance of establishing a written set of maintenance and playability standards. By putting categories like day-to-day green speed, firm, fast or green, lush gives the golf course superintendent a lot of flexibility. For example, a hypothetical course has established a maintenance standard of 9 foot green speeds every day. By simply stating this standard allows the golf course superintendent to vary practices to achieve this ball speed. Viable options would be alternating mowing and rolling, switching to smooth rollers, and raising the mowing height in an attempt to minimize turf loss. I do understand that setting maintenance standards may not work for each situation, but it may be something to try especially at a public play facility. You may think I am crazy for talking about this, but based on my observations this summer establishing a set of maintenance standards seemed to work.

This is also the time to start thinking about snow mold applications. Here is a link for our snow mold trials for 2009-2010. The key with these reports is to look at the treatments that provided the best control (lowest disease severity) at the site closest to your site. We test a wide variety of chemicals and combinations at five locations in order to provide golf course superintendents with a plethora of options. We do not distill the reports down to the top ten best products because the best products and combinations may not be within the budget of many golf courses. So we always recommend finding the product or products that provide the best control and fit within the constraints of your budget.



Timing of snow mold fungicides was a fairly hot issue early this spring, largely due to some perceived failures of very good snow mold fungicides. We still do not have a great answer, so are initiating a fairly large fungicide timing experiment this fall. We expect to see good control from systemic products when they are applied well before snow cover, and good control from contacts closer to snow cover. We will let you know next spring, so stay tuned.

Update from the American Phytopathological Meetings

The Midwest is still struggling with heat, humidity and persistent rainfall. As a result, most of the Poa annua in the Midwest is either dead or struggling to say the least. Since I am sitting in the Charlotte airport, I asked Paul Koch for an update on the samples coming into the Turfgrass Diagnostic Lab. It appears that brown patch, Pythium blight and anthracnose are still raging. Our sample numbers are way ahead of last year's entire amount!

It seems that John's post on Monday has caused quite the stir amongst the followers, but he is exactly correct. This is not a "calendar year"! The summer has sucked for most superintendents throughout the US. Grass is dying everywhere and the typical actions like raising the mowing height, alternating mowing and rolling, and other techniques are not helping like we'd like. I think the MOST important thing for golf course superintendents to do is start a line of communication with the owner, membership, golfer, general manager about losing turf. Regardless of the reason or diagnosis this is a banner year for losing turf.

For anyone that knows me I am not a pessimist, but when soil temperatures are above 90 degrees turf is going to have trouble. These temperatures can lead to disease development especially with the amount of rainfall we have had in the Midwest. However, many times grass just dies due to abiotic conditions like poor drainage, anaerobic conditions and heat stress. Remember that annual bluegrass and creeping bentgrass are cool-season grass and prefer to grow when soil temperatures are between 55 and 75 F. Not 90 to 100 F! Lets face it even bermudagrass will struggle when soil temperatures exceed 95 F.

Regarding bacterial wilt, a turfgrass system is a very dynamic biological entity. Many microbes inhabit the rhizosphere of turfgrass plants, which can make turfgrass disease diagnosis extremely difficult. In almost every sample that comes through the TDL, we can find numerous turfgrass pathogens. Furthermore the scientific community is finding that many bacterial species are common epiphytes (live on the surface of leaves) and endophytes (live inside the plant). That being said, it is very common to find bacterial streaming from stressed turfgrass plants. However the signs need to match the symptoms observed in the field and it seems like these two are not jiving.

In my humble opinion, it seems like bacterial wilt has become the perfect fall guy for a brutal summer. It's perfect because it is a mysterious disease with very few effective control measures, but we also have very few control measures for nature.

Summary of a Presentation from APS:

This year's APS meeting was great! Some of the turfgrass pathologist got the opportunity to visit a few golf courses in NC. I was amazed on how quickly I have acclimated to the summers of Wisconsin, damn its hot down there! I really did not have a favorite presentation at this year's meeting. I think the most interesting aspect of the meeting was a special session on Rhizoctonia diseases in turf. There was some fantastic information presented ranging from taxonomic considerations for this genus, biology and management of brown ring patch, management of leaf and sheath spot of ultradwarf bermudagrasses and finally using digital imaging software as a tool to score and identify host resistance in turfgrasses. There was so much information in this session, but the best part was how collegial the speakers were to one another.

Each speaker reference each other and it seemed that they were all working together to help fill in some major gaps with the Rhizoctonia and Rhizoctonia-like diseases in turfgrass. It is cool to be a part of this group, all of my colleagues are extremely helpful and willing to collaborate on projects. As a result, I think we will see many enigmatic problems in turf solved fairly quickly.

Not All Pythium Diseases are Created Equal

With the excruciating heat and humidity plaguing the Northeast, Southeast and Midwest, there has been numerous mentions of the notorious Pythium. Even the news media has caught wind of this nasty fungal-like organism (maybe that's why the columnist called it a bacterium). Check out Lane's post this week if you want to see what I am talking about.

So why are Pythium diseases problematic when the temperatures rise and relative humidity is through the roof? Pythium species are members of the Oomycota, which are commonly called water-molds. These organisms used to be classified as true fungi, but morphological and molecular evidence show that members of the Oomycota are more closely related to diatoms and brown algae. Yeah I know you don't care, but I do believe in the quote from The Art of War by Sun Tzu- "Know thy enemy and know thy self and you will win a hundred battles." It is vital to understand the pathogens you fight on a daily basis.

We have seen a number of different diseases induced by Pythium species, such as Pythium blight, Pythium root rot and even Pythium root dysfunction. However, the symptoms, signs and conditions favorable for disease development are different for these three diseases. Considering the recent weather conditions, I thought it would be good to review the differences between these diseases as well as the management strategies.

Pythium Blight- This disease has been the subject of nightmares for golf course superintendents for years. The fear most likely steams from the days when Pythium aphanidermatum developed resistance to metalaxyl and entire fairways were wiped out rapidly. Today we rarely hear of entire fairways devastated by Pythium blight, but the disease can develop even the Upper Midwest. However, the development is typically centralized around a drain or low lying area. If the disease is not controlled and hot, humid conditions persist the disease could spread at an alarming rate. Usually we only have 2 to 4 weeks of heat and humidity conducive for Pythium blight development in the Midwest, yet this summer has been a bit different than normal.

The symptoms of Pythium blight start as small, gray spots that can coalesce into larger areas of blight fairly quickly. Typically development of this disease will occur around drains or low lying areas of fairways. The picture just above the heading of Pythium blight is typical of the symptoms we see on creeping bentgrass in the Midwest. Cottony, white mycelium may also be present during early morning hours when dew is present. As for management, its a good idea to start thinking about Pythium blight when nighttime temperatures are above 70 to 75 degrees and when there is plenty of soil moisture. Fungicides that work best are Subdue MAXX, Stellar and Segway. Other products that may have varied results are Banol and Terrazole. Keep in mind that Signature works, but only when pressure is light to moderate.



Pythium root rot- Pythium root rot can be a major problem of golf course putting greens when there is persistent heat, humidity and low light intensity. This disease is also a problem on putting greens with limited air movement. One of the major problems with this particular disease is we know very little about the pathosystem. Consequently most the control recommendations are based on observations made by golf course superintendents. I think Lane posted about Pythium root rot sometime last summer and talked about the issues surrounding this disease.

The symptoms are usually diffuse, irregular areas that exhibit decline. The affected areas can decline quite rapidly because the pathogens destroy root tissue. The picture above is an example of typical stand symptoms. A noticeable decline in root depth is usually observed within affected patches. If you suspect Pythium root rot is an issue at your course, I suggest sending a sample to your local turfgrass pathologist for confirmation. Usually the best medicine for Pythium root rot is a Terrazole drench. Unfortunately, this disease can still develop even if you are on a good Pythium preventative program. Remember that most turfgrass fungicides only move up from the point of absorption, so in order to get Pythium root rot activity the fungicide needs to be washed into the rootzone.

Pythium root dysfunction- I know this is confusing, but Pythium root dysfunction is a totally different beast that Pythium root rot. The conditions that favor Pythium root dysfunction (PRD) symptom develop are hot, dry conditions not hot, humid conditions. PRD shows its ugly head on upland areas and develops into a discrete patch. Normally this disease is problematic for young putting greens built with high-sand content rootzones. I have blabbed on for a while on this post so check out a previous post by Lane for PRD management strategies.

To bring this belaboring post to an end, if you suspect any Pythium induced disease have it diagnosed by your local turfgrass pathologist. These diseases should not be taken lightly and all of them have different management strategies.

Rainfall and Fairy Rings Throughout the Midwest

Our wet weather has continued throughout the Midwest. Accompanying the wet weather, has been heat- at least heat for us. I feel guilty saying we are hot when I saw the temperatures forecast for the Northeast and Southeast. On the weather channel this evening a couple took a picture of a bank marquee showing temperatures in New Jersey topping 100 degrees! However, we have been in the upper 80's, which is hot for us. Consequently we have seen anthracnose, brown patch and dare I say even some Pythium blight. Don't freak out about Pythium blight because it was only observed near leaky heads or drainage areas.

I have seen a lot of is fairy ring over the last few weeks. It appears to be more prevalent this year compared to last. If fairy ring has been problematic the best way to control the disease is to apply DMI fungicides (Bayleton, Tourney, Triton FLO and Trinity) when 5- day average soil temperatures are between 55 and 65 degress. However, we have moved out of this range in most places in the Midwest. Curatively, an application or two of Prostar (flutolanil) will help alliviate symptoms, especially when the applications follow solid tine aerficiation. If solid tining is not an option than a wetting agent should be tank mixed with the fungicide. Some golf course superintendents have good luck masking symptoms with applications of wetting agents, nitrogen and/or iron. This may be an excellent approach for a large breakout on fairways. If you have more questions about fairy ring, please attend our WTA Summer Field Day on July 27th! Dr. Lee Miller is going to join us to talk about his research on fairy ring.

With respect to diagnosing fairy ring, my best advice is to be like Tucan Sam and follow your nose. The thatch layer underneath the affected area will have a nice mushroomy aroma. You may also notice the thatch may have an orange tint. Another nice technique is to "incubate" a sample in a moist chamber, which is a tupperware container with a moist paper towel underneath the sample. The image below demonstrates the results of an incubation. I still encourage golf course superintendents to send a sample to a local turfgrass disease diagnostic lab if symptoms present themselves in an odd fashion.



Last week I had the great pleasure of showing Dr. Megan Kennelly around the OJ Noer Facility. It was a nice morning and the only disease I was able to show her was dollar spot. One of our putting greens has essentially become a 10,000 square foot dollar spot! I hope one day we can have Megan back to talk about her research on moss and nozzles (just to name a few topics), I think golf course superintendents in the Midwest would enjoy hearing her speak.

Yesterday was another pleasure, a few of us from UW Madison traveled to Whistling Straits to visit with the staff about the upcoming PGA Championship. We had a great visit and we also were given the opportunity to play golf. I cannot wait to see how the pros handle the course this year. I know I had trouble with the long grass a few times! I heard a rumor that John is visiting the Straits this weekend. Wonder if he'll experience the long grass a few times...

Greetings from the Midwest

Hello from the Midwest! I have been on hiatus from the blog because of a family issue that popped up. The main news from the Midwest has been the extremely warm spring. Most places in the Midwest experienced the second or third warmest spring on record. Samples have been rolling in to the Turfgrass Diagnostic Lab (TDL), but there has not been a consistent trend in our diagnoses. In other words, no single disease has dominated the Midwest. With the recent weather conditions, at least in Wisconsin, turfgrass is very happy! The picture to the right documents the average daily temperature from May 17 to now, which has been fairly warm for us.

We have seen a little bit of brown patch develop a few weeks ago when we were very hot and humid. Dollar spot has been seen throughout the Midwest and was first observed about two weeks ago. What a difference a year can make! Last year we were still dealing with snow mold and winter injury this time last year. This year we are already fretting over brown patch and dollar spot.

We have had a few samples already with symptoms characteristic of take all patch. After looking at the samples we had to do a double take, because it is way too early for take all patch. Again we had to keep in mind the extremely warm and early spring we experienced. We have had a few samples submitted complaining of small, yellow, irregular patches that developed in mid to late April. Typically the patches persist until early to mid-June and were on fairly young putting greens. We did not observe much pathogen activity in the foliage or root tissue, but isolations seem to indicate that a fungal or fungal like organism is associated with these symptoms. Dr. Lane Tredway has seen similar symptoms in North Carolina and did not find significant pathogen activity. Maybe later this week or next we can figure out what the fungus (fungi) is associated with the affected tissue.

Although we have had a warm spring, we have had significant, localized rainfall amounts . So some golf courses have experienced increased play volumes, while others have noticed similar levels to last year. The weekend forecast does not look promising for the Madison area, which stinks! Especially considering the fantastic day we had yesterday, it was 60 degrees with rain all day.

I'm glad I am back to the blog and plan to post weekly once again! The one main point I wanted to make this week was if you have not made your first dollar spot application, tomorrow would likely be good timing considering the forecast for the weekend. Have a good week and weekend! On a final note, remember the Wisconsin Turfgrass Association Summer Field is July 27th, so mark your calendars.