Pythium, algae, brown patch, flooding and more

I returned from the International Turfgrass Society meetings on Friday afternoon and was greeted to a slew of new diseases in the region. At the research facility, algae and brown patch were taking off due to the recent rains and high temperatures. The recent rains were not without their own problems as it caused major flooding at various golf courses in the region. Most notably, Merion Golf Club had many bunkers wash out and even had holes under water for a period of time (Image of hole #11 fairway and green, courtesy Matt Shaffer). Also hanging on in many regions is the Type II fairy ring species on both putting greens and fairways. I have yet to see these rings collapse in the Northeast, but it is likely that some superintendents are dealing with more severe cases.

Dr. Landschoot indicated that Pythium blight was also active on his fine leaf fescue variety trials. Although I hadn't seen any Pythium around the facility, I did notice that half of my Kentucky bluegrass lawn was wiped out on the side of my house. This area receives little light or air movement and has a swale that carries the water from about 10 properties away from entering my basement!

Overall, I would say that this summer has been a cake walk as far as disease and heat problems are concerned. Although we are not completely out of the woods, we are getting close.

On the lookout...I have not heard any reports of gray leaf spot yet, but this is one disease that is likely just around the corner and preventive treatments should now be close or in place already depending on your location.

Do you have anything happening at your course worth sharing? If so, feel free to add your story to the comments section or send images to be included in a future posting!

OH! I almost forgot, everyone keep an eye out for Frank Wong's posting this week from the American Phytopathology Society Meetings in Portland. I hear they are seeing some interesting things in the streets of Portland this week!

Stress & 'todes

It’s always hard to follow Frank’s posts. I mean, what can I write after he applies “If it’s yellow, let it mellow” to turf disease?

The big concerns lately have been brown patch, foliar Pythium, stress, and nematodes.

While brown patch seems to have decreased somewhat from our surprise late June epidemic, I suspect that it will come surging back in with our forecasts of more heat, humidity, and rain.

Dollar spot has totally disappeared from our research plots. Too hot!

As for foliar Pythium, the rains keep coming, nighttime lows remain high, and the sites with the disease are on high alert. Most have put down one or more applications of a Pythium fungicide and are watching for new activity.

Stress? That is on the plate every week. In some recent samples, waterlogged soils have clearly caused root decline with some secondary Pythium nibbling on the aftermath. We still can’t seem to dry out in some areas.

The photo illustrates a stress problem where greens received a little too much N, got puffy, then scalped. You can see the scalped spots right at the edge where the mower hit the green.

Nematodes in turf are a tricky subject. There was a lot of discussion earlier this week amongst turf pathologists about damage thresholds in nematodes. Damage thresholds are hard to pin down, and the potential damage of a certain population of nematodes varies with the overall amount of stress at the site. Sometimes there is a correlation between turf damage and nematodes; often there is not. Usually there are multiple factors in play.

One nematode that is pretty well documented to cause damage even at low numbers is sting nematode. We picked up sting in a sample a few days ago. I heard Dr. Mike Fidanza (Penn State) joke one time, “If you want to spread news, what are the 3 best ways to do it? 1) Telephone. 2) Telegraph. 3) Tell-a-superintendent.” That is, news travels fast in this industry. After the sting finding, we had a sudden flush of requests for nematode testing because the word had gotten out. Numbers of all plant pathogenic nematodes were pretty low, and no sting nemas were detected anywhere else.

brown patch, pythium, and summer stresses

Hot and humid is the big story this week. Waterlogged soils are an issue in some areas, both in sand-based greens and native soils.

We are starting to see lots of typical summer decline. Poa annua is checking out, and algae and hot spots are checking in. In areas where bentgrass has been stressed, it’s showing decline too. June feels too early to be dealing with this stuff, but that is what Mother Nature has dealt us this year. If June is kicking our butts, I'm worried what July and August have in store.

With the overly wet conditions, some guys are wanting to needle tine and topdress to get some air movement in their putting greens. But, it’s so hot, such cultural practices could seriously stress out the turf. We are all hoping for some cooler temps next week in order to sneak in some cultural practices. A dip in nighttime lows would really be beneficial. The lows over the past week have been in the 70’s in most of Kansas (a bit lower in western Kansas where humidity is lower), and soil temps at 4-inches are hovering around 80 degrees. We might get some highs in the upper 80's (gee, maybe I'll need a jacket or I might get chilly...) and lows in the mid-60's early next week. Then, the forecast calls for more scorching.

I had a couple of interesting diagnostic cases this week where turf was declining and, as is typical this time of year, no turf pathogens were to blame. In one situation, a surfactant was applied as part of a tank mix and then not watered in, and this may have led to some phytotoxicity especially in our hot conditions. A big clue was that the practice green WAS watered in, and that one was not showing damage.

In another, some extra N a couple of weeks ago kicked the turf into high gear on one putting green. The green got a little puffy, then got scalped, and now it is having a hard time recovering in these conditions.

The turf shown in the photo below is not happy to be drowning:

Here is this morning in pictures, to further illustrate the conditions

It’s SO humid…

* My camera fogged up when I first took it out of the case at the turfgrass research facility at 7:00 am. No that’s not real fog in the photo, that’s condensation on my camera lens. It took about 5 minutes to "equilibrate" to the outside air.

* The dew was thick to the point of sloshiness:

* I could hear the brown patch mycelium crawling around (well, not quite, but almost…):

* Pythium blight is making its first appearance: (mycelium had been present earlier)