A Cornucopia of Disease in Southeast Asia

I sometimes find such healthy grass that I have little disease to write about, but this week was an exceptional one. I went from Kanchanaburi to Bangkok, Singapore, and Da Nang, seeing a number of grasses and on them an assortment of pathogens. Click the thumbnails for a full-size image and description.

If there were an award for diseases, seashore paspalum would win this week, with two different unidentified diseases and slime mold and dollar spot, with a bonus for some extraordinary drought stress. In the image below, there is an unidentified patch disease and dollar spot on a seashore paspalum fairway in Bangkok. And you can see the drought stress in the drain lines going to the catch basin in the background. But wait! Can you see the patch of Zoysia matrella in the center-left of the photo? The Zoysia matrella that is free of disease and doesn't have the drought stress of the paspalum even though it is growing in the drain line? Seashore paspalum does not grow well at all in Southeast Asia in areas of low soil moisture content.

Seashore paspalum grows wild in tidal swamps and in intertidal zones. Which is exactly where I found it growing on the beach at Da Nang (below), in its natural environment, and free of diseases. But come in from the beach a short distance, where the high tide does not reach, and I found wiry Zoysia matrella growing in the dunes.

There was brown patch on bermudagrass at Vietnam and bermudagrass white leaf, which I think is the most unsightly disease, on bermudagrass at Singapore and Vietnam.

Most of the diseases, you notice, were on seashore paspalum and bermudagrass. I saw two types of broadleaf carpetgrass this week, both free of any disease. This grass thrives in the umbrageous conditions so ubiquitous in tropical Southeast Asia, as does zoysiagrass.

And for those more interested in cool-season grasses, you probably read with some interest the post from Dr. Kerns and Dr. Soldat a few weeks ago about managing potassium on cool-season turf. I'm fascinated by the Park Grass experiment and its results showing that potassium and lime application cause a proliferation of dandelions and other weeds, and the most recent issue of the Green Section Record has an article with some insights into that experiment and how the results "carry lessons of high importance in the growing of golf turf."

Dead Bentgrass Makes Headlines

Well, you know things are rough when the local media is writing about Pythium, aerification, and MiniVerde bermudagrass. Unfortunately that's where we are here in North Carolina and many other parts of the southeast. Check out the following article from last Thursday's Charlotte Observer: 


Hot Weather Turning Putting Greens to Toast


Overall, I think its a pretty accurate description of the struggles that golf courses are facing in the region. I'd be curious to hear everyone's thoughts. There are also a couple of factual errors in the article. I'll give a prize to the first people to point them out by leaving a comment on this post!


A lot of people have been asking about converting their greens to ultradwarf bermudagrasses. They are definitely a good option in certain situations, and several courses in the area have made the switch with great success.


My only advice is this: if you can't maintain good bentgrass greens because of problems with shade, air movement, or soil drainage, then you won't be able to maintain good bermudagrass greens either. The courses that have been most successful in converting to ultradwarfs also removed trees, improved air movement, and corrected drainage problems. Who knows, maybe bentgrass would be doing just fine with these improved growing conditions?

K-State research update

Hello,

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

1) Zoysia sun/shade study

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

The photos show the plots on the day of installation.

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

2) Bentgrass cultivar trial: management for dollar spot

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

3) Brown patch fungicide trial

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

4) Putting greens and DMI PGR effects

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



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