Viridescent - the Asian Turfgrass Center blog

Understanding Data Use for Turf Management: presentation slides (with video) from Thailand

This week I spoke to a full room of turfgrass managers at Bangkok's Thana City Golf and Sport Club about an important topic: understanding data for use in turfgrass management. I've recorded this video of the presentation slides in which I discuss the two classes of data that can be collected – data about playing surface performance, or data about plant growth – and then I go into some detail about soil moisture and photosynthetically active radiation (PAR), with a brief mention of salinity and soil pH at the end.

There were many questions and an active discussion in this seminar and in fact lunch time arrived before I could speak about salinity and soil pH, so this video provides the narration of what I would have talked about had there been more time.

David Lau from Spectrum Technologies, pictured with me at right, gave an interesting presentation in which he talked about a broad range of meters and software that can be used to collect and analyze information for improving turfgrass performance. This is part of what PACE Turf call Precision Turfgrass Management (PTM), which is a systematic effort to provide optimum turf performance using minimum resources. As David mentioned, we cannot manage something if we do not measure it.

For more information about the data I discussed, you may be interested to read this report about putting green performance, including extensive sections and data on soil moisture and temperature, and this report about photosynthetic irradiance.

10 Years Ago Today, a Startling Observation About Potassium and Snow Mold

Ten years ago today, I was a graduate student at Cornell University, and after the snow had melted off of the research green, I walked over to the research area to check the condition of my experiment. It was a cold day, in early spring, and I took this picture not noticing so much about the differences in snow mold incidence on the L-93 creeping bentgrass of this experiment. It was not until April (see below) that I really noticed what a huge difference there was between the different fertilizer treatments.

In the previous summer, the turf was all the same, showing no visual response to any application (or withholding) of potassium (K) fertilizer.

And in the autumn of 2002, just before the snow would fall and would cover the green for months, there was no difference at all in turf performance.

The previous summer the turf was all the same, no matter how much K was applied, and in November before the snow the turf was all the same also. There was more K in the leaves where K had been applied, and there was more K in the soil, where K had been applied, but the visual appearance of the turf was all the same. 

I did not apply any fungicides to this experimental area in the autumn of 2002. 

In the spring of 2003, when the snow melted, I expected that all the plots would be the same, as they were in November before the snow fell.

So it was a startling observation to find that there was more snow mold damage on the plots to which K had been applied in the previous year. The plots with more available K in the soil, and the plots with more K in the leaves, had more damage from snow mold than did the plots to which no K was applied at all the previous year!

I wrote about this in my article summarizing this experiment. Continuing research by Moody and Rossi has shed more light on just what it is that may cause this phenomenon. 

Application of K when it is not required may cause unexpected problems. By using the MLSN guidelines to determine when K fertilizer is required, one can have confidence that unnecessary fertilizer applications are being avoided.

An Exemplary Guide to Control of Turfgrass Diseases

One of the best guides to control of turfgrass diseases is this one: Chemical Control of Turfgrass Diseases 2013 by Dr. Paul Vincelli and Dr. Gregg Munshaw from the University of Kentucky. 

In just 24 pages, this guide covers it all. And it is free! Topics covered include:

• Contact and systemic fungicides
• Preventative and curative use of fungicides
• Details on more than 40 fungicidal and biological control products
• Advice on cultural methods to reduce disease
• Management recommendations for more than 25 turfgrass diseases
• Links to additional information

This is a document that I use for reference throughout the year and I have now updated my files with the 2013 version. If you find it as useful as I do, you should do the same. Download it here.

Another turfgrass disease reference that I use frequently is the Compendium of Turfgrass Diseases. 

Related articles

Soil and Water Testing for Turfgrass: valuable tool, or absurd pretense?

Turfgrass Fertilizers: an exemplary fact sheet

Turfgrass Mystery: how was this bunker revetted?

Why is there cool-season grass in Philadelphia and warm-season grass in Seoul?

We can look at temperature data for Seoul and Philadelphia and we find that the average temperatures throughout the year have almost complete overlap. So we might expect that with such similar temperatures on a month by month basis, the grasses used in those cities would be similar. But while the courses at Philadelphia are mostly cool-season grasses, what we find at Seoul are primarily courses planted to Zoysia japonica. Here is a dormant zoysia fairway near Seoul in early spring.

Why such a different choice of grass when the temperatures are the same? I suggest that it has to do with summer precipitation. 

From June through September, Seoul has a higher monthly average rainfall than does Philadelphia, and during the two hottest months of the year, July and August, Seoul has more than three times the rainfall, on average, than does Philadelphia. This combination of high temperature with high precipitation can be deadly for cool season grasses.

Customize the chart yourself to see data for other cities.

Data: korea • Chart ID: ATC_climate_chart_Korea

R version 2.15.0 (2012-03-30) • googleVis-0.2.16
• Google Terms of Use • Data Policy

Golf Course Maintenance at Japan: week 1, remote controlled golf carts, large patch, and the two green system

I'm in the midst of three weeks at Japan. Some of the issues related to golf course maintenance and golf in general at Japan are so interesting, and so challenging, that a few updates about course maintenance here will surely be interesting. First, though, the ghost cart, that ubiquitous remote-controlled cart that is found all over Japan.

You'll have noticed another interesting thing in the video. I've taken the video while standing on one green that has recently been core aerified and topdressed, while the golfer is playing to another green on the same hole. Many courses in Japan use this two green system. Of the eight golf clubs I visited last week, five had 18 holes, one had 36 holes, one had 54 holes, and one had 72 holes. That's a total of fourteen 18 hole equavalent courses.

But, in Japan, there is more to it than that, because eight of those fourteen courses use the two green system, with two greens on each hole. So at the eight clubs that I visited, there were actually 396 greens, not counting practice greens or nursery greens. Japan has a large golf industry, with more than 2,400 courses, but when it comes to maintenance requirements for putting greens, the most highly-maintained area of any golf course, there are much more than 2,400 courses worth of greens, because so many courses use the two green system.

The image above (from Google Maps) shows a 36 hole club near Tokyo with the two green system, so there are 72 creeping bentgrass greens at this club. This image also shows the course in two seasons, with the holes at left in summer, when the Zoysia matrella fairways and Zoysia japonica roughs are green, and with the holes at right showing the dormant zoysia in the winter.

Japan is very much in the transition zone, and that means large patch (Rhizoctonia solani) is a problem on the zoysia, particularly on the Z. japonica. It is worst in areas with poor drainage and in areas with moderate to high thatch. In this swale in the rough of a golf course, the large patch is thriving.

Another problem on many of the courses I visited was moss. I saw moss on Zoysia matrella (korai) greens. When we take a close look at the green, we can see that in the areas in between the korai leaves, the moss is growing. 

Moss is even more of a problem on creeping bentgrass greens in Japan, and I saw plenty of that as well.

Of course, the climate in Japan is quite a challenge for growing creeping bentgrass, because of the high temperatures during summer. We can look at the climatological normals and see that the city of Fukuoka in West Japan (in yellow on the chart below), the temperatures throughout the year are similar to Atlanta (in blue), with Fukuoka being a bit hotter during the summer. With those types of temperatures, it would seem that ultradwarf bermudagrass may be a good choice in that part of Japan, and many golf courses are now testing ultradwarf bermudagrasses such as Miniverde or Champion Dwarf. 

However, although the temperatures are similar at Atlanta and Fukuoka, Atlanta has a lot more sunshine, as can be seen in the chart below. Ultradwarf bermudagrasses can grow well at Japan but because of the limited light for photosynthesis, the management of the grass requires substantial adjusments from the way it is managed in the Southeastern United States.

At Atlanta, there are more than 250 hours of monthly sunshine from April to September, on average, while at Fukuoka there are only 150 to 200 hours of sunshine each month during that same time period. This difference in light has a big effect on the performance of bermudagrass. 

With all the challenges of the climate for creeping bentgrass, the challenging climate in general because of low sunshine combined with high temperatures, the possibilities of using ultradwarf bermudagrass, the large number of putting greens relative to the number of courses because of the two green system, and just the sheer number of golf courses, Japan is an exciting place to study (and work) about golf course maintenance. And there is a lot of unique maintenance equipment too. More about that coming up in another post.

Turfgrass Disease Reference Guides

Last week at a seminar in Ho Chi Minh City, there was a question about how to choose which fungicides to apply to control certain turfgrass diseases. A reference that I find especially useful, because it is updated, packed full of information in only 24 pages, and is freely available from the University of Kentucky, is the Chemical Control of Turfgrass Diseases 2012 guide written by Paul Vincelli and David Williams.

Another excellent and free resource is the NC State University TurfFiles website's disease section. For more general information about turfgrass diseases, the TurfDiseases website and associated Facebook page, twitter feed, and Google+ page are good places to find information. 

The book that I always keep handy is the Compendium of Turfgrass Diseases, 3^rd Edition. This comprehensive guide covers the diagnosis and control of approximately 80 diseases and is packed with useful photographs of various warm- and cool-season turfgrass diseases.

Can You Identify the Grass and the Disease?

Can you identify the grass and the disease? This is a warm-season grass, in Southeast Asia, maintained at a mowing height of about 25 mm (1 inch). The average temperature during this season is about 17°C. Answer to be posted in a few days. 

Answer: This is seashore paspalum (Paspalum vaginatum) showing typical symptoms of dollar spot. Seashore paspalum grows most rapidly when average temperatures are more than 25°C. With the temperature at less than the optimum for seashore paspalum growth, but within the optimum range for dollar spot to grow, we can see this type of severe damage.

For some advice about dollar spot control on seashore paspalum in Asia, see this post from the Turf Diseases website:

Suggestions on the Right Maintenance for the Wrong Grass

Turfgrass Teaching and Research at Oregon State University

Last week I had the opportunity to visit Oregon State University to teach one session of Dr. Rob Golembiewski's Principles of Turfgrass Maintenance class. In the morning lecture, I spoke about turfgrass maintenance in Asia and what some of the distinguishing differences are compared with typical turfgrass management in the Pacific Northwest. In the afternoon, I met with the turf club to discuss internships, career opportunities, and some of the interesting things about working in the turfgrass industry in Asia. 

I also visited the turfgrass research farm and saw the various grasses and experimental trials. Brian McDonald is the research assistant for turf management at OSU and he showed me some of the interesting research being done with fertilizer trials, fungicides, herbicides, mowing and rolling, irrigation, grass variety trials, divot recovery, and even some seashore paspalum research. My interest in turfgrass research started when I did earthworm control and herbicide research at this farm in 1998, just before graduating from OSU. 

The amount of research being done now is impressive and I got to see a lot of Poa annua, perennial ryegrass, red thread, pink snow mold, brown blight -- all grasses or diseases that I don't see all the time when I am working with warm-season grasses. Every time I got down for a close inspection of grass disease symptoms, June the Research Cat came over to say hello. She is, I'm informed, the farm's environmentally-friendly method of rodent control.

For more information about the turfgrass program at Oregon State University, check out www.beaverturf.com.

New Information on Diseases and Cation Exchange Capacity

I've been really busy in the past month, returning to Thailand after the exciting Masters Tournament, traveling to Singapore, Vietnam, and Sri Lanka, studying, and writing. Thanks to @daisukeiw who sent me the image above of the layout for my new series in Golf Course Seminar magazine. Pitchcare Oceania have just published a panel report on cation exchange capacity (CEC) and have featured some comments from me about CEC in sand rootzones and how it can be estimated most accurately by using an equation in which the only variables are soil pH and soil organic matter content.

I've also made some international updates to the Turf Diseases website. Some of my recent posts on that site are:

Large Patch Resistance of Zoysia?

A Cornucopia of Disease in Southeast Asia

Healthy Grass = Little Disease

Potassium, Hokkaido, and Snow Mold

Turfgrass Diseases in India

What is the Most Interesting Disease in the World?

Mites, a Corpse Plant, and Native Grasses

Large Patch on Zoysiagrass

More About Seashore Paspalum

A Most Unsightly Disease

The Wow Factor, Seashore Paspalum, and Dollar Spot

Collecting Dollar Spot With Dr. Tredway in Southeast Asia

Turfgrass pathologist Dr. Lane Tredway from North Carolina State University recently made a visit to Southeast Asia for the purpose of collecting dollar spot samples. From ATC's Thailand base, we went to Vietnam, Malaysia, and the Philippines to collect dollar spot from many different grass types: bermudagrass, zoysia, seashore paspalum, carpetgrass, creeping bentgrass — even from some sedges. There is not much creeping bentgrass in Southeast Asia but we traveled to high elevations to find it at Dalat in Vietnam, at the spectacular Mount Kinabalu Golf Club in Sabah (below), and at Camp John Hay in Baguio.

Dr. Tredway has chronicled this trip in a post entitled Dollar Spot Expedition to Southeast Asia on the Turf Diseases website. 

Dollar spot is ubiquitous and is especially so on seashore paspalum turf. This project looks at the different strains of dollar spot as they are found on different grass types and in different geographical and climatic areas. The idea is that a better understanding of the dollar spot pathogen itself will allow for the development of better control measures for this disease in the future.