Pythium, Crop Science Recaps and Dr. Bob Endo

It's been a rough few weeks....
Well folks, it's been a rough few weeks for a number of us, especially if you're a Democratic, Pot Smoking, Texas Rangers fan. Superintendents in the West are still having a good amount of diseases. Anthracnose has been diagnosed from Poa greens from several locations ranging from southern California to Washington State and a freak rash of Pythium, large patch and even pink snow mold broke out on warm season turf in California about 2-3 weeks ago.

Here's a shot of bermudagrass from southern California that was hit with Pythium graminicola around October 25.



Above normal temperatures in the 90s in the second week of October followed by a solid week of cool, wet weather likely triggered the freak appearance of the disease on warm season turf in southern California. Although Pythium is normally thought of as a hot weather disease, anytime you have lots of moisture and weakened plants, there's a window of opportunity for Pythium to break out.

I've been getting several calls from superintendents in the Pacific Northwest asking about Pythium this week. The winter of 2009-2010 is likely one that a lot of guys from that area would want to forget. Although we did diagnose Pythium root rot from several courses there last winter, a hot summer followed by early freezes in December was also to blame for some of the widespread damage that was seen on greens.

My best advice or PNW guys going into the winter this year is to try to improve surface and soil drainage as much as possible and apply a preventive systemic Pythium fungicide prior to wet weather. The Pythiums we diagnosed last year tended to be considered 'weak' pathogens like P. torulosum so hopefully a little prevention will go a long way this winter in avoiding any turf loss due to these pathogens. Just in case any body was wondering, we did not pick up any P. volutum (Pythium root dysfunction) from the PNW last year associated with the winterkill on Poa greens. However we have found it one time in eastern Washington on creeping bentgrass, but it does not appear to be common in the West at this time.

Q: What do you call 50 turf nerds on a bus in southern California? A: The Crop Science Turf Tour.
As some of my colleagues mentioned this week, a number of us were at the Crop Science Society Meetings in Long Beach California from Oct 31 to Nov 3. About 50 turf scientists from all over the U.S. had the pleasure of visiting Riviera Country Club, Bel Air Country Club and Jackie Robinson stadium at UCLA last Oct 31st.

Co-organizer Larry Stowell put together this quick video recap you can see here:
http://www.youtube.com/user/paceturf#p/u/8/OPecrWGUtDY

Thanks again to Matt Morton at Riviera, Brian Sullivan, Nic Hoisington and Justin Carroll at Bel Air, Kevin Borg and Chris Romo at UCLA and Greg Fukumitsu and Dean Mosdell from Syngenta Professional Products for helping us put together a successful event for these turf science geeks!

Anthracnose Action from the Crop Science Society Meetings
Although I didn't have a chance to catch all of the plant disease talks at the Crop Science Society Meeting, here are a few highlights from some of the research presented there (I'll continue to highlight some of the presentations over the next few weeks as time allows):

Charles Schmid, James Hempfling and Joseph Roberts (Rutgers University)
In a series of three talks looking at cultural control impacts on anthracnose severity, these three students in the labs of Bruce Clarke and Jim Murphy, help shed some more light on factors that affected anthracnose severity.

Chas Schmid's research on nitrogen effects showed that both low and high nitrogen rates applied in the summer caused more anthracnose than moderate rates. An experimental putting green was treated with 0.1 to 0.5 lb N (ammonium nitrate) per 1,000 sq ft at 7-day intervals in June and mid-July to mid-August. The most anthracnose was found in plots treated-weekly with 0.1, 0.4 and 0.5 lb N while those treated with 0.2 and 0.3 lb N per 1,000 sq ft had the least amount of disease. Again, it goes to show that anthracnose is a disease of the 'sickly' --- greens that are too lean or too fat are more likely to get disease vs. ones that have 'adequate' nitrogen fertility.

James Hempfling examined the effects of spring and summer sand top-dressing on anthracnose development. Greens were topdressed with either 0, 3.9 or 7.9 cu ft of sand per 1,000 sq ft in the spring or 0, 0.25, 0.49, 0.98, or 1.97 cu ft of sand per 1,000 sq ft at 14-day intervals in the summer. Not surprisingly, the 7.9 cu ft rate in the spring was more effective than 3.9 or 0 cu ft rates in reducing disease and at least 0.98 cu ft of sand had to be applied in the summer to get a significant reduction in anthracnose. Bottom line: sand topdressing is your friend when it comes to reducing anthracnose severity.

Joe Roberts presented his research on the effects of greens rolling on anthracnose. He used both a vibratory roller and heavier sidewinder roller in his experiments. Rolling every other day reduced disease by 2 to 13%, and surprisingly, the effect of the sidewinder rollers was slightly better than the vibratory rollers. He also observed that areas that received higher equipment traffic also tended to have slightly less disease. The mechanism of this reduction is still under investigation, but it did show that rolling can be an effective cultural practice in helping to prevent anthracnose on putting greens.

Dr. Robert M. Endo (1925-2010)

Dr. Endo's research helped identify Ophiosphaerella korrae as one of the causal agents of Spring Dead Spot

Last week, I was very saddened to learn of the passing of Dr. Bob Endo. He was a University of California (Los Angeles and then Riverside) professor for 30 years who made significant contributions to the understanding of dollar spot, southern blight, and spring dead spot

http://www.legacy.com/obituaries/pe/obituary.aspx?page=lifestory&pid=146497989

Dr. Endo was also one of the Japanese-American volunteers who formed the 442nd Infantry Regiment in World War II. Despite facing questions of loyalty to the U.S. and being placed into internment camps after the bombing of Pearl Harbor, these men volunteered for duty and served in combat in Italy, France and Germany, gaining the distinction of the most highly decorated regiment in the history of the US Armed Forces.

http://en.wikipedia.org/wiki/442nd_Infantry_Regiment_(United_States)

Dr. Endo will be missed by all who knew him.

Until next week, signing off from the Right Coast....

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!

More on the DMIs and Bermudagrass Greens

It is often said that good research raises more questions than it answers. Maybe the same can be said about blog posts? And no, I am not referring to Megan's California Gurls post from last Friday. (Side note: My main motivation for posting today was to bury that thing as quickly as possible. No pun intended.)

In last week's post about Torque for spring dead spot and fairy ring control, I casually mentioned that tebuconazole can injure ultradwarf bermudagrass putting greens. Since then, I've had a lot of questions about Torque and other DMIs and their safety on bermudagrass greens. It's a complex issue, and one that we don't have all of the answers to. Your questions will motivate us to do more research on this next year.

Although many of the newer DMI fungicides on the market are more safe on cool-season putting greens, they can be more injurious on bermudagrass greens. Looking at the graph to the left, you see that applications of Trinity (triticonazole) and Lynx (tebuconazole) caused severe damage to Tifeagle bermudagrass, Bayleton caused a slight reduction in quality, and Banner and Eagle had no effect. This is almost exactly the opposite of what you would see on creeping bentgrass or annual bluegrass putting greens.

Of course, application rate and time of year influence the amount of injury that is caused by DMIs, with the greatest injury caused by high rates, repeated applications, and high temperatures. You will notice that in the above example, we made 5 applications in a row at high label rates during the heat of the summer. No wonder some of them caused injury!

However, don't make the mistake of thinking that that all of the DMIs are safe on the ultradwarfs in the fall and spring or if you're only making one application. As an example, refer to my post from last fall entitled Effects of DMI Fungicides on Bermudagrass Putting Greens. In this example, we saw pretty significant phytotoxicity from some of the DMIs even after one application when temperatures were relatively mild.

I don't mean to scare everyone away from using the DMIs. We never see issues on bermudagrass fairways or athletic fields, and some of the DMIs are perfectly safe on greens. Just choose your products wisely and don't jump on the newest products right away just because they are new!

Moss, root rots, and Snoop Dogg

Hello from a chilly Manhattan,

I was unable to attend the turf agronomy meetings this week due to some other travel. The conference was in Long Beach, CA. Until I have some proof showing me otherwise, I am going to assume that Frank, Jim, Jon, and Lane spent their time in CA doing a re-make of California Gurls (yes, apparently it's gurls, not girls). I'm not sure which one was Katy Perry, though I vote Lane for Snoop Dogg.


I was bummed to miss the research presentations and I am hoping that the other guys can fill us in. A student, Cole Thompson, that I am co-advising with Dr. Jack Fry, presented some of his work on control of silvery thread moss. In some prior research at KSU, in conjunction with Derek Settle in Chicago, we observed some promising moss control with spot-sprays of baking soda (sodium bicarbonate). However spot sprays can be labor-intensive. And, there was a little bit of tip-burn.
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So, in a follow-up study on 2009-2010 we looked at some different rates of baking soda in addition to a potassium bicarbonate product. The idea was to try to tweak the rates and application methods to get moss control without the phyto, and maybe with less labor. As a standard we included Quicksilver, and then we also included MossBuster which is an oil-based product.

In 2009 we had some control with Quicksilver, MossBuster, and the high rate spot sprays of both bicarbonate products. In 2010 nothing reduced moss compared to the untreated.

The turf quality aspects were interesting. MossBuster and the bicarbonate treatments caused some reductions in turf quality due to phytotoxicity, and the MossBuster plots sometimes took 2 weeks or more to return to acceptable quality. Quicksilver did not cause any phyto either year.


Speaking of moss...

I talked about moss during a seminar last week and a colleague (from Minnesota) said with a smile, "You did not mention the most important moss, and that is Randy Moss."

That got me thinking, and I did a quick search. Though these headlines/quotes are about Randy, I prefer to think of them in the context of silvery-thread moss:


Moss does not have a great deal of respect for male authority


Moss' talents should be a better fit with what Titans need


With Moss gone, Vikings receivers in the spotlight


Joe Biddle wonders if Moss is the boost needed for a Super Bowl run or a recipe for disaster.


The Titans think Moss can put them over the top, says Thomas George.


Alex Marvez rates Moss as the NFL’s biggest baby.


Vikings receivers had a lot of praise for Moss.


A Team Gathers No Moss

The ultimate root rot experience

I received some basil plants the other day. I know, basil is not turf or ornamental, but the process I’m going to describe is relevant to other kinds of plants. Click the images for a closer look.

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The top parts of the plants looked fine, nice and green:

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But, if you look close, you can see some discoloration around the crown. When I washed the soil off it was clear that something was very wrong with the roots.

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There weren’t any! Well, there weren’t many, and the ones that were there were dark and mushy, with the outer tissue sloughing off:

When I see this, I usually think of Pythium.

I made a slide:

And in the microscope I found two types of Pythium spores. The one below shows a structure called a sporangium that is starting to form a vesicle (the bubble on the end):

In addition, we have a test kit for Pythium. I cut up some tissue at the transition of the healthy and symptomatic areas:

Then, I ground it up in some buffer that comes with the test kit. After that, I placed a few drops onto the indicator strip:

… and then waited a few minutes. The C-line below stands for control, and it shows that the kit is working. If no C-line shows up the test is not valid. The T (“test”) line also turned color, indicating a positive result.

Out of curiosity, I also tested for Phytophthora. Pythium and Phytophthora are fairly closely related, and I was wondering if there might be any cross reaction. You can see in the photo that on the Phytophthora test, only the C-line turned positive.

Pythium (and Phytophthora) root rots are usually associated with overly wet conditions, and this particular operation did have some potential water management problems that they will now address.

In the landscape, like in a greenhouse, if you have a Pythium root rot that usually means that the underlying problem is really a moisture problem.

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.