Dr. Vincelli's Chemical Control of Turfgrass Diseases

For those of you who have not yet seen this reference from Dr. Paul Vincelli at the University of Kentucky, you will be excited about this post. Dr. Vincelli has been pulling data from the Plant Disease Management Reports (formerly F&N Tests) for a number of years and he continues to update this reference each year. I have to say that it is one of the best references available that continues to provide current fungicide recommendations based on field research conducted throughout the United States.

Access the original Chemical Control of Turfgrass Diseases 2011 here. (current disease update below)

Vincelli Fungicide Chart


Update on diseases this week:
Brown patch and Pythium blight are very active in the mid-Atlantic and northeastern US at the moment as would be expected. Anthracnose also appears to be making some inroads on annual bluegrass putting greens. A big decision has been whether to apply the DMI fungicide tebuconazole (Torque, QP-Tebuconazole, others?) during the summer heat. This has consistently been one of the most effective anthracnose products in trials throughout the US. In our trials this year, we have not had any significant injury or regulation from repeated applications of tebuconazole, but I will note that our site is not as hot as others in the region AND we are not applying any growth regulators in our trial area. I don't have an answer as to whether you should apply it or not, but I guess it would depend on how much Poa you have, how healthy your greens currently are, and how bad your anthracnose is.

Spring dead spot of zoysiagrass

Spring dead spot of bermudagrass

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

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

Spring dead spot of zoysiagrass?

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

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

Spring dead spot of 'El Toro' zoysiagrass

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

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

Spring dead spot of 'Diamond' zoysiagrass

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

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

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!

Waitea Patch trials give me the Hives

Let's try something different this week!

Shot on an iPhone4 and edited with iMovie.

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!

New Granular Fungicides for Turf

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

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

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

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

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

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

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!

A New Option for Spring Dead Spot and Fairy Ring Control

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

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

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

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

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

Anthracnose, Summer Patch, F-bombs, Nematodes and Cee Lo

Anthracnose & Summer Patch in California

'Hey - Did-ya Miss Me?' Anthacnose was plentiful in the UCR diagnostic lab this week

I was back in California this week and greeted with triple digit temperatures - normally I'd say the dry heat of California is better than the steamy heat of Washington DC, but 112 degrees in Riverside was still pretty bad!

I always say that anytime we get wide temperature swings, anthracnose is likely to rear its ugly head, and this last week was no exception - Naveen was getting quite a few of these samples in the lab.

As John had mentioned earlier this week, summer patch has been pretty active on annual bluegrass greens and we saw it on a few samples in California as well. Back in the 'good old days' of the 90's, it seemed like anthracnose and summer patch control went hand in hand, but recent developments have resulted in some 'complications'.

As we all know, anthracnose has become the primary concern of most guys out there with annual bluegrass greens, but summer patch can often be a hidden problem. Here are two observations regarding summer patch development this year.

#1 Targeting Anthracnose but Forgetting About Summer Patch
Sixty-five to sixty-eight degrees soil temperature in the spring is the magic range for initiating anthracnose & summer patch control programs with 2 to 3 applications of DMI-fungicides like Banner MAXX, Trinity, Triton, Tourney or Torque, but after that, control diverges quickly for these diseases. Fungicides like the Heritage (azoxystrobin) and Insignia (pyraclostrobin) are my top choices for summer patch control (thiophanate-methyl, e.g. 3336, is also a consideration), and should be applied monthly in the summer to keep summer patch in check. But....as we all know, anthracnose resistance to the QoIs and benzimidazoles in many locations makes these ineffective for anthracnose control. For mid-summer applications, products like chlorothalonil (Daconil), fludioxonil (Medallion), polyoxin-D (Endorse/Affirm) and Signature (Fosetyl-Al + StressGard pigment) are my go to materials. DMIs can also be effective, but applied in the summer heat may cause some unwanted PGR effects.

Superintendents worried primarily about anthracnose may be applying anthracnose-fungicides but forgetting to use Heritage & Insignia on a monthly program. As a result, summer patch can break through what seems like a good program that is unfortunately tailored specifically for anthracnose.

#2 Compass vs Insignia in Rapid Blight Control Programs & Effect on Summer Patch
Rapid blight is another disease that California superintendents battle in the spring and summer, and Compass (trifloxystrobin) and Insignia are the 'go to' systemic fungicides for rapid blight control (mancozeb is our only contact option), but differ in their physical properties. Compass is very strong as a foliar fungicide, but less systemic than Insignia and will not give you effective summer patch control. If you've been using Compass regularly in the summer, remember that you could be under-gunned for summer patch control, and have to apply additional materials.

Bottom Line: Anthracnose, summer patch and rapid blight management require specific fungicides - choose wisely and know what fungicides won't give you any overlap in disease control.

Anthracnose Rescue Fungicide Programs
If you have anthracnose breaking out on greens, it is most likely that you (i) have had a serious stress event, (ii) are too lean on fertility or (iii) have had a lapse in fungicide protection in your program.

Notice that 2/3 of the 'issues' are not fungicide-related. Correcting cultural practices and fertility is the top priority, but here are some thoughts on a 'rescue' program for active anthracnose outbreaks.

1. DO NOT BOMB IT WITH QOIs/STROBIES OR T-METHYL FUNGICIDES EVEN IF THEY STILL WORK FOR YOU. That is a recipe for resistance, big time! Anthracnose is already a high-risk pathogen when it comes to QoI and benzimidazole fungicides, and using them as 'eradiciants' in this way increases the chance of selecting out resistant populations.
2. CHLOROTHALONIL IS YOUR FRIEND. This is partially why I encourage guys to save up some of your 10 or so chlorothalonil applications for the summer. Chlorothalonil will not 'cure' existing infections, but can kill spores developing in acervuli and prevent new infections (if you let your foliar anthracnose go all the way in to the crowns, you're hosed, don't wait til that happens as you won't be able to get on top of it with fungicides in the summer). Being a contact fungicide, you will need to apply frequently to ensure that you have lasting coverage on plants. Applying the normal label rate, at a shorter application interval, is likely more effective than the max. rate once or at longer intervals.
3. MEDALLION, ENDORSE & AFFIRM --- These are 'limited systemic' fungicides and can give you added control of anthracnose, but are at moderate risk for fungicide resistance. I would not encourage them to be used as 'eradicants' but you can apply them to help with protecting plants once you have the active outbreaks arrested with aggressive chlorothalonil use. Right now, there is no resistance to these, & we want to keep it this way for the time being.
4. SIGNATURE, ALIETTE, & PHOSPHITES --- These have for the most part, 'indirect effects' on anthracnose, and will not work as 'eradicants'. The data I've seen shows that the active molecule in these fungicides is not super-toxic to anthracnose, and provide protection via induced plant defenses or other mechanisms; and you guys know how I feel about StressGard pigment being a good thing for annual bluegrass in the summer. Tank mixing them with your chlorothalonil will give you added protection but they will be acting on healthy plants vs. new infections and not directly killing the active anthracnose.

F-Bombs, Nematodes and Cee-Lo
Ok - I've gotten some (for the most part) good natured ribbing from some guys this week about my comments on Turf Net regarding what we know about nematodes.

http://www.turfnet.com/view_news.php?obj_id=606

Call me crass, but the F-word is strongly correlated with the discussion of turf diseases; it's one of those words that in its various forms has use as a noun, verb or adjective, especially when discussing anthracnose, summer patch or rapid blight, and annual bluegrass in general.

On the other hand, in all seriousness regarding the comments, we really don't know enough about nematodes on turf, and really really don't have enough chemical controls for the problems - making me drop the F-bomb to drive home the point.

Compared to the 30 or so university turf pathologists in the US and dozen or so different fungicide active ingredients, we have like 4 turf nematologists (Crowe, McClure, Wick & Mitkowski come to mind) and 1 nematicide (Curfew), plus any Nemacur stockpiled in the shed, that can control nematodes down in the soil .

You know I love me some fungus, but considering the issues caused by nematodes like root knot, stem & gall (Anguina), spiral, sting and others, and more importantly - the high amount of "mis-information" about nematodes and their control out there - it's a good time to put some attention and funds towards this. That's my 2% of a dollar.

Finally, if you can't get enough of the F-Bomb, check out Atlanta-based Cee Lo's new music single and song here:
http://www.youtube.com/ceelogreen#p/u/1/CAV0XrbEwNc

(WARNING: DEFINITELY NOT SAFE FOR WORK OR CHILDREN)

If you're not offended by the F-bomb and like Old School Motown-Style R&B, it's certainly worth a listen. I suspect they will have taken this one down from the internet by the time you read this blog today, but I'm sure you'll hear about this one soon.

OK - Back in DC as of the Morning and Signing off from the Right Coast.....

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.

Of Fungicide Programs and Control Plots...

Well, I'm sitting here this evening having spent the day looking at plots that for most of our audience would make you cringe, but for me, has me doing cartwheels! The images you see in this post are from my fungicide program trial. This trial allows for multiple applications of various fungicides on a set schedule (usually a 14 day interval), and an evaluation of the diseases that occur in various plots along the way. This year has been epic in the Southeast. Heat, humidity, and regular rainfalls have combined to push the stress levels to unprecedented levels. In an more 'usual' year we would get some brown patch, dollar spot, and if we were lucky some fairy ring to evaluate. This year we have seen the following turfgrass diseases in these plots: dollar spot, brown patch, fairy ring, Pythium blight, and anthracnose. It is clear from thephotos what programs are holding their own under the pressure, which ones are doing ok but have some weaknesses, and those (including controls) that just aren't cutting the mustard.In the area, we have observed much of the same problems as the last several weeks; heat and humidity stressed turf. We have had a cooling off period this week, but that is really a misnomer

because whiles the highs are in the upper 80's, the lows are in the mid-upper 70's and the humidity is thick enough you feel like you should be swimming to the next tee. As the various golf organizations have declared in their statements- this is the time for defensive turfgrass management. Translated- do what you need to do to maintain turfgrass cover, and worry about greenspeeds later. Also pay close attention to water management (see image) as these issues

can take a toll in the form of black layer.

Finally, from a fungicide program perspective, take the time now to make some notes on what you think was weak about your current program while it is fresh in your mind. Also, note things that you would change and improve, because with the summer we have had you might be able to show the folks involved on your greens committee or general management that skipping cultural practices, or fungicide applications might just be a fool's errand chasing the almighty dollar.

Here's to a little cool-down!

Brandon

Dude, where's my summer?

Downright Pleasant in California

Growing up in the Central Valley of California, I remember those long Fresno summers of 20-30+ 100-degree days where even the normally pasty-white, redheaded kids of Irish descent were sporting tans that made George Hamilton look like a albino naked mole rat, and the Channel 26 TV reporters were regularly frying eggs on the sidewalk outside of the Fashion Fair Mall.

Well, this ain't one of those summers in California. Aside from some short heat spells, it's been pretty damn mild, with temps being in the 70's on the coasts, 90's inland and only hitting triple digits in places like Fresno and Palm Springs this week.

Having spent the last week at the APS meetings in Charlotte in the company of all of the U.S. turf pathologists, it was nice to avoid being in the middle of discussions about heat-killed turfgrass and the hot potato talk of bacterial wilt.

On the other hand, we're seeing some weird disease patterns emerging from our diagnostic lab. The last two weeks have brought in diagnoses like anthracnose on creeping bentgrass (samples from Alameda, Tulare and Sacramento counties) and Curvularia blight on bermudagrass from Arizona. The presence of both diseases are likely attributed to some kind of 'stress' (irrigation, compaction, low fertility, etc.) as both anthracnose and Curvularia are typically very weak pathogens on these turf species.

We're also getting some rapid blight samples from southern and central coast locations. I am guessing that the cooler than normal temperatures (70-85F is optimal for rapid blight), fog or overcast conditions are helping that disease fire. We were surprising very low for rapid blight diagnoses this Spring, but the current Spring-like conditions in these areas has just pushed the calendar back a few months for courses at these locations.

It could very well be one of the best years in recent memory for growing grass in California; and guess where I am --- 3,000 miles away in Washington DC this summer!

Steamed & Drowned on the East Coast

While my friends back home are enjoying the mild summer, I'm alternately being steamed and drowned here in Alexandria, VA. Like much of the south and midwest (see Lane, Jim, Megan and John's recent blogs), the DC area has been gripped by prolonged heat broken by violent thunderstorms. Just last Thursday, I and about 60,000 other residents in the DC area lost power after heavy rain and winds ripped through the area. It happened again today - check out the story here:

Check out the link on the Turf Disease Facebook Page here: http://www.facebook.com/turfdiseases

Somehow, that southern California smog may not be all that bad to deal with.....

News from the APS Meetings: Fungicides (or Lack Thereof)

As the rest of the boys (plus Dr. K) were saying, we've been at the APS meetings all week - well, except for Lane who was answering frantic calls from superintendents and going back and forth from site visits to the meeting almost every day (the man had a microscope in his hotel room to look at disease samples - that's dedication for you!).

One thing that struck me was the lack of new fungicide active ingredients being discussed that are effective for turfgrass disease control. There was a good amount of buzz over, ametoctradin, a new BASF oomycete-fungicide for downy mildew and Phytophthora control, but sadly this one isn't effective vs the Pythiums that we deal with on turf. I hope we see some new fungicides for turf soon - we could use them!

There were also a good number of SDHI-resistance talks, but mainly on Botrytis, not turf diseases. SDHI's are the succinate-dehydrogense inhibitors, that include boscalid (Emerald) and flutolanil (ProStar). I have a hunch that we'll eventually see more broad-spectrum SDHIs for turf diseases in the future, but we'll have to keep waiting for the time being. The good news about this research is that we're going to able to use their Botrytis information to detect and help deal with SDHI-resistance for turfgrass diseases when it happens.

OK - until next week, signing off from the right coast.....

Happy Summer! Wait- didn’t that happen about 2 1/2 weeks ago?

Well, the disease season is off to a rip roaring start. In the transition zone and southeast we have had multiple days this month that have been in the 90’s with high humidities, and warm nights not much below 70. That kind of weather translates to serious disease. Dollar spot, brown patch (below), even some potential for pythium blight. It is clear from the photo to the right (Upper left plot is untreated) that having a preventative fungicide program is crucial to achieve successful disease control.

We have had an earlier than usual disease startup, but all in all it looks like our trials are off to an excellent start. Fungicide programs that are showing the best early results are those with Signature and Daconil as a backbone as well as those that have some form of StressGard in them. Also, programs using Syngenta products are performing well too. Fungicide programs with post-patent products, and a straight Daconil 7-day program are starting to curb some dollar spot that was present prior to the trial initiation and both of those programs are demonstrating good disease control into their second applications. On the dollar spot front, most everything that we are applying is working, and we are getting good disease control. Our controls however, continue to highlight the importance of good fertility (since we are only using 0.25# N/1000/month).

Finally, UT had a groundbreaking last Friday for our 1.5 million dollar Center for Safer Athletic Fields that has been funded by AstroTurf. The 5th first-round draft pick for the Kansas City Chiefs, Eric Berry was on hand to lend his endorsement, and we are excited to be building a facility that will provide funding for athletic field research on a scale that has only been seen in golf turf research previously. Look for more regular posts from the Southeast now that Summer is officially here!!

Blue Skies, Nothing But Blue Skies...

The last post focused on my final thoughts on snow mold and since then the weather in the Upper Midwest has been great! We have had a very early spring. This is good for the golf industry because golfers have been able to play golf! The last couple of weekends have not been nice, but at least some weekday play is occurring. The TDL, my phone and email have been fairly quiet with respect to turfgrass problems. We have been very dry the last month or so and this week has been extremely windy. When I was still at NCSU, Lane used to make a very simple point to his students-What is most important to a fungus? WATER! We haven't seen or heard of a lot leaf spot development because of the dry spring. The only interesting symptoms we have seen are some unusual reddish brown rings on one of our putting greens at the OJ Noer. Upon incubation of the affected turf, we obtained a Rhizoctonia like fungus. The cultures are only a few days old, so I don't know what fungus it is yet. The reddish brown rings were a little unusual though.

Besides the development of this little anomaly, we have been busy laying out our summer fungicide trials. We have also been busy planning our summer field day, which is scheduled for July 27th. We are changing the format slightly this and we are still planning on conducting the afternoon Lawn Care Session that focuses on basic turfgrass management skills. The topics include, grass ID, weed ID, sprayer and spreader calibration and pest identification. We are kicking around having a congruent session that focuses on advanced turfgrass management skills, like soil moisture measurement and interpretation, disease diagnosis and fungicide program development and insect management. If you think this would interest you please let me know!

I think this summer will present some interesting challenges as most summers do. We also have a whole lot going on so stay tuned! Next week I will be in Lane's state for a much needed beach vacation, maybe I'll report on the turf I see there :). Before I go the picture attached to the post is a representation of one of my most favorite cities! We were out on the lake during mid-April!

Final Thoughts on Snow Mold This Spring

All of our snow mold trials have been rated this year. In our most southern site in Milwaukee and in Minneapolis, MN, snow mold did not develop. However, in Stevens Point, WI, Marquette, MI and Brainerd, MN we had phenomenal pressure. Especially at our Marquette site, which is shown in the image on the right. So I don't beat a dead horse too much, the idea with snow mold control is to mix products or use pre-mixed products. Mixtures of two or three of the following active ingredients, trifloxystrobin, iprodione, triticonazole, myclobutanil, propiconazole, thiophanate-methyl, chlorothalonil or fludioxonil, performed well at all of our sites. Check our website in a couple of weeks for this year's results! And if you are in the area stop in at one of our Snow Mold Field Days- April 14th (Brainerd, MN) April 15th (Stevens Point, WI) and April 16th (Marquette, MI). Please get in touch with myself or Paul Koch (plkoch@wisc.edu) if you would like specific information about these events.

The issue with snow mold control I do want to address is breakthrough. Many individuals experienced breakthrough with some products that traditionally do exceptionally well in our trials. So what is going on? I believe it is a timing issue. In our trials we typically apply fungicides at least two weeks prior to snow cover and many times a month prior to snow cover. Typhula sclerotia (survival structure) are thought to germinate when soil temperatures reach 32 F or soon after snow fall and then the mycelium would initiate an infection. So you are probably thinking then it is best to wait as long as possible to apply fungicides for snow mold control. Well that may not be the case. Recent research at UW-Madison regarding fall nitrogen applications shows that only 10 % of the nitrogen applied in November actually makes into the turfgrass plant. Transpiration is minimal during this time, therefore acropetal penetrants are likely not moving within the plant. Remember that acropetal penetrants like propiconazole, myclobutanil and thiophanate-methyl, enter the plant move in the xylem with the transpirational stream.

Basically when applications are applied very late in the year, the fungicide is likely only on or within the cuticle layer and not within the plant. If coverage is poor or infection occurred prior to snow fall (as is likely the case with Microdochium nivale), then a bit of breakthrough will occur. Then each year breakthrough occurs, inoculum levels will increase and eventually the chemical practice implemented is overwhelmed. All of this is just thinking out loud, but my predecessor Dr. Gail Worf always recommended applying fungicides for snow molds before deer season (Gun) opens in Wisconsin. This is normally the third weekend in November, which is typically 2 to 5 weeks before snow fall (that persists) in the Madison area.

We are doing some research to shed some light on these questions I have raised. One of my students Paul Koch, is examining the degradation rate of the fungicides chlorothalonil and iprodione in the absence and presence of snow cover. He has found that we can expect disease suppression with these two products for at least 28 days in a winter environment. We have yet to detect a difference between degradation rates of these two fungicides in the absence or presence of snow cover. Admittedly however, we are still doing some data crunching and this may change once our statistical analysis is completed. Then this fall we are going to conduct a fungicide timing study to determine when snow mold fungicides should be applied. In this study we will use a small number of fungicides representing at least one contact, systemic and a mixture of both types of fungicides. We have not worked out the exact details at this time, so any comments would be appreciated!

Besides snow mold, we have seen a few odd problems this spring. One in particular was fairly severe damage from what appeared to be fairy ring on a stand of Kentucky bluegrass grown on pure sand. The stand symptoms were necrotic rings with an orange tint and a strong mushroom aroma to the thatch layer. When we incubated the sample, a fungus with large clamp connections popped out the thatch. The odd thing about this problem, was the necrotic rings were present immediately after snow melt. There was type II fairy ring symptoms in this field prior to snow cover, so maybe the dark green areas were more susceptible to winter injury is my theory. Maybe others have seen this with fairy ring or maybe I was totally off with my diagnosis, once again any thoughts or comments on this would be appreciated. Next Wednesday is one of our Snow Mold Field Day dates, so I will likely not post anything. Hopefully I will see some of you there!

Weather! What the...?

For those of you not paying attention to the weather in State College (as I am sure most of you don't), all I can say is WTH. State College received the earliest snow on record and it was not met with much happiness. For one thing, the leaves are still on all the trees and the heavy snow caused a lot of damage. The image to the right shows some of the damage that I witnessed outside the house on my way to work. In addition to this, I was without electricity for 2 days. This wouldn't have been such a problem except to keep warm, I had the gas fireplace going only to wake up in the middle of the night with the carbon monoxide detector going off. Needless to say, I had some trouble getting back to sleep that night!

SO...as you can imagine there are not a lot of diseases in State College at this point, but around other parts of the Northeast golf course superintendents are preparing for snow mold applications. According to this weeks survey, superintendents are also participating in the numerous early-season purchasing programs offered by many of the manufacturers. This is one area that is gaining popularity and a few researchers are putting together programs related to the economics of turfgrass management.

SO...as I have tried to do all year (with little success due to the lurkers in here), I will once again try to find out what you (our readers) are planning for next year. For those of you buying on the early-order programs, what is it that you are looking for and how do you plan your purchases for the upcoming year?

If you feel inclined to do so, feel free to leave your answers in the comments.

AND...for those of you lurking and not feeling like answering, you can check out what others are doing with some superintendent blogs that I like to read!

http://therimgolfclub.blogspot.com/
http://cccpgcm.blogspot.com/
http://ergcm.blogspot.com/
http://geccgcm.blogspot.com/
http://creekmoormaintenance.blogspot.com/
http://greensuper.blogspot.com/
http://pinetreegm.blogspot.com/
http://sandstonegolf.blogspot.com/
http://sgccturf.blogspot.com/

Is it fall already? Not quite...

Cooler temperatures across much of the southeast are going to bring a much needed break from summer this week. Most of our summer-time bentgrass diseases, like anthracnose, Pythium root rot, and brown patch, should start to shut down as the bentgrass begins to grow more vigorously.

It's nice to have a little reprieve, but be sure not to let your guard down. These summer diseases can re-activate quickly if temperatures rise again in the coming weeks. The picture to the right of a severe brown patch outbreak was taken in September 2004 after a period of warm, wet weather. Be especially wary during periods of wet weather or when major aerification and/or topdressing practices are planned.

If you've had problems with Pythium root rot this summer, additional fungicide applications are a good idea during wet weather, such as a tropical storm system. If you've had anthracnose problems this summer, a fungicide application just after aerification/topdressing is a good idea as well, as these abrasive practices can cause a flare in anthracnose activity.

Of course, dollar spot should start to become more active as the temperatures cool over the next month. If this disease has been a major problem for you in the past, be sure to start preventive applications soon before symptoms of the disease appear. Once the symptoms appear, dollar spot becomes much more aggressive and difficult to control.

For those with bermudagrass greens, this is the time of year when leaf spot diseases, such as Curvularia and Bipolaris, start to come in. Preventive fungicide applications for these diseases are recommended during wet, cloudy weather or after topdressing applications. Chlorothalonil typically does a good job of keeping these diseases suppressed, but if you are looking for something that lasts longer, iprodione is a good choice.

Most people think of Pythium blight as a hot weather disease, but on bermudagrass greens, most of our problems with this disease are during cool, wet weather in the fall and spring. The image to the right of Pythium blight symptoms was taken on Champion bermudagrass greens last October. In this case, the symptoms appeared very similar to a leaf spot disease, but typical leaf spot fungicides were not controlling it. Once a sample was diagnoses as Pythium blight at our Turf Diagnostics Lab, the problem was easily controlled with an application of mefanoxam (Subdue Maxx).

Soon it will be time to start thinking about controlling large patch and spring dead spot in the warm-season grasses. Stay tuned - this will be the topic of next week's post.

Dans la Merde in the West

Dans la merde is a colorful French term that basically translates into "in the sh*t" and is a good term to describe superintendnets who are currently behind the eight ball fighting active foliar anthracnose outbreaks on annual bluegrass greens in the West.

Right now, anthracnose is coming into our diagnostic lab left and right. It's likely a result of the up and down heat spikes and we've had throughout the summer here in the west.

Although anthracnose should be managed with a combination of solid cultural practices (see www.turf.rutgers.edu/research/GCM-BMP-Anthracnose.pdf) and a solid preventive fungicide program, summer stress and common practices related to tournament prep (low mowing heights, holding back N, drying down greens, etc.) or just high traffic and play can put superintendents in a bad spot. If you find yourself dans le merde, here are three suggestions that may help you get back on top of anthracnose before it's too late

(There are additional things you can do to help pull yourself out of an anthracnose outbreak, these are just three of the most common things to consider - I'd welcome any additional comments from the NE, SE, M and SC as well!)

1. Fungicide applications
If you have active anthracnose on greens, chlorothalonil is your friend. Inexpensive and not at risk for resistance, it can be used aggressively as a "eradicant" application to kill spores in acervuli and prevent new infections. Label rate applications 7 days apart should be made to halt infections in their tracks. You can mix chlorothalonil fungicides with other anthracnose-active fungicides like Medallion and Endorse safely in a rescue type situation. Chipco Signature tank mixed with chlorothalonil can also be a good option. DMI-fungicides like Banner MAXX can also be mixed with chlorothalonil, but be aware of potential PGR-effects when using these at high rates or high temperatures. Beware of using QoIs (Heritage, Insignia, Compass, Disarm) or thiophanate-methyl containing fungicides (Clearys 3336, Fungo, etc.) by themselves as rescue applications. Resistance is a problem for these already and using them as rescue materials is a good way to lose them due to resistance (that's a GCSAA class all to itself). In any case, chlorothalonil can do a lot of work for you as a rescue fungicide, and also beat back any other secondary pathogens coming in to the damaged areas or algae that can fill into thinned areas on greens.

When using contact fungicides like chlorothalonil, it's very important to get good coverage. Apply fungicides in at least 2 gallons of water per 1,000 sq ft for adequate penetration of the fungicide to the lower leaves and crown. Flat fan or air-induction flat fan type nozzles, that produce smaller sized droplets, are much more effective than rain drop or flooding wide angle nozzles for getting the best coverage with contact fungicides.

2. Fertility
Assuming that you can get sufficient knock down of he pathogen, it's important that surviving Poa has enough N to push back and recover from injury. Light applications of N (0.125 to 0.25 lb N/1,000 sq ft) should be made to get your Poa back on its feet. Apply as needed to get regrowth and recovery from damage; but excessive amounts may cause some excess growth and scalping if you're not careful. Although N is the most important component, additional P and K can also help. A 20-20-20 may be a good choice for recovery from anthracnose damage.

3. Irrigation
Once you're hit with anthracnose, don't overwater damaged areas in hopes of increasing damage recovery. Overwatering is just as conducive for anthracnose as is drought stress. Irrigate based on ET-needs, but make sure to mist/syringe greens in during the hottest periods of the afternoon to minimize heat stress on weakened plants.

Hopefully, with some TLC (plus fungicides, nitrogen and irrigation management), you can get outta the merde and back to normal practices on greens. Often, anthracnose is linked to other environmental conditions or agronomic practices (compaction, black layer, drought stress, etc.), so make sure to address those issues as well while you are in "rescue" mode.

Just an observation: If your anthracnose if plowing right through preventive Heritage, Compass or Insignia applications…. Guess what, your anthracnose is probably QoI-resistant. If your anthracnose is plowing through preventive 3336 applications (or any thiophante-methyl containing material), you've probably got benzimidazole resistance. Check out our anthracnose powerpoint here if you haven't already seen it for some chemical control alternatives: http://www.turfpathology.ucr.edu/Downloads/anthracnose_chemical_control.pdf

Other Merde...
Over the last week, we've been absolutely slammed by diagnostic samples in the lab. In addition to anthracnose, the usual suspects are still active, such as brown ring patch, summer patch and rapid blight. Samples coming in with Bipolaris, Curvularia, and Leptosphaerulina (especially on fairway and rough samples) are indicative of summer heat stress on cool season turf.

With temps in the 70s and 80s in coastal locations, I would suspect rapid blight be pretty active in salt affected locations, as well as brown ring patch and even dollar spot. The Central Valley (Fresno) and deserts will have to contend with night time temperatures high enough to flare Pythium on cool season turf. Expect anthracnose and summer patch to be calling on your annual bluegrass greens through out the state.

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

Novel Dollar Spot Control Programs

Dollar spot has really been the only challenge this year for golf course superintendents. With the recent economic downturn we are investigating ways to help superintendents reduce fungicide expenditures while maintaining quality playing surfaces. I have mentioned our dollar spot forecasting project, in collaboration with Dr. Damon Smith at Oklahoma State University, in previous posts. We are applying the preliminary model Dr. Smith developed in Oklahoma in our environment in Wisconsin. To date, the model has accurately predicted dollar spot development and making applications based on the model has resulted in 4 fungicide applications this year. When we compare efficacy to other fungicides either applied on 14-day intervals or 21-day intervals, the forecasting model holds up well. The one exception was a high pressure weekend and some dollar spot developed in the forecasting plots. The graph at the top left of this post depicts our results so far this year. The red arrows indicate when the model triggered and the blue arrows indicate when we made a fungicide application for just the forecasting plots.

The model did trigger before June 22 as a result we made a fungicide application on June 16th. Typical dollar spot programs in the Upper Midwest start on June 1, which would result in 7 applications when repeated every 14 days. For the 21 day treatments we have made 5 applications so far. Either case we can save either 1 or 3 applications per year. Currently we are putting numbers to these savings. We are using a municipal course, high-end public, mid-range private and an elite private course. Hopefully this will make are numbers relevant for a lot of turf managers. Please stay tuned because there is more to come!

Another project we are working on is expanding early-season dollar spot control. Basically we made a single early-season application and followed those applications up with 3/4 rates of Banner Maxx/Daconil every 21 days or full rates of Banner Maxx/Daconil every 28 days. Interestingly, full rates applied on 28 day intervals are providing the same level of control as our conventional program. We have not started our economic analysis of this project, but I know we have saved at least one fungicide application in this experiment. Again please stay tuned to this project too.

I am very excited about Lane's post yesterday! I saw the data with Civatas and I was excited, but we have not tested the product in the Upper Midwest. I know Dr. Derek Settle has, yet I cannot remember what he found. Civitas is scheduled in our snow mold trials this year, so we will see how it holds up. As always nice work Lane.

Megan's story about visiting with Aron Hogden is pretty funny. Poor Aron thought she was just a normal person coming over to lecture him about spraying. Aron had no idea that he peaked the interest of a turfgrass pathologist! Megan you are lucky you got out there without an inqusition from Aron.