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Tag: Pythium root rot

Sad, soggy roots and some Pythium root rot in turf

Posted on by kennelly

(Megan Kennelly, KSU Plant Pathology)

 

“We got six inches of rain, and the golfers are saying, ‘Hey, isn’t it great for the turf that we are getting all this rain?’ Hah – Not exactly!”

That was part of a recent conversation with a superintendent in south central Kansas. Yes, moisture is good, but not 6 inches all at once! It seems that this year the water is either OFF or ON. When it is OFF it is really OFF. When it is ON, it is coming down in buckets. I guess nobody gets exactly what they want when they need it.

We continue to see poor rootzones on all kinds of plants, from trees to turf to tomatoes to petunias. Putting greens are really suffering. I’m seeing lots of brown, mushy roots with tissue sloughing off.  Poa annua is also checking out in the heat, big time.

Below are some pics of roots. These are some older pics I have posted before, but they look just like most of the roots I’ve been looking at for the past couple of weeks. In some cases Pythium root rot is occurring as well, but in many cases the turf seems to be declining all on its own. For example, I had some samples where multiple plugs were submitted from multiple greens. All the roots were in poor health, but I found Pythium (at a low level) in just a few of them.

Root images:

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What to do?

Check out the post today from Dr. Fry with some tips about managing bentgrass to prevent summer decline. Click HERE.

Another great set of tips is outlined HERE, starting on page 6, from U of Kentucky.

For Pythium root rot, here is an excellent site from NCSU, where Dr. Jim Kerns has conducted research on this disease.

http://www.turffiles.ncsu.edu/diseases/pythium-root-rot

In current research, Dr. Kerns reported in a Tweet that he also saw good results with Signature Xtra watered in (click HERE).

To date, we have not had a different disease, Pythium root dysfunction, occur in Kansas. At least, I have not seen it any any samples run through KSU. I did just learn from our neighbor Dr. Lee Miller at U. of Missouri that they picked up that disease in St. Louis. Lee mentions it in his update HERE if you want to learn a little more about it.

 

Pythium root rot in putting greens

Posted on by kennelly

Jared Hoyle mentioned that he has been getting some questions on Pythium root rot, and last week, our neighbor to the east Dr. Lee Miller at University of Missouri wrote in a great post (click HERE) that he has already seen some Pythium root rot samples from putting greens with all the wet conditions. Even in the absence of Pythium in the roots, heavy rains in spring = poor root growth = turf more likely to crash and burn when summer conditions kick in. Add Pythium and that can make it even worse. In his article, Dr. Miller also provided a caution that some of the materials superintendents apply in spring such as pre-emergent herbicides, DMI fungicides, and PGRs could be limiting root growth in spring and setting up the grass for more problems. His comment is observational from comments from superintendents but is definitely interesting and as he states, probably some research is needed.

In another excellent recent post from NCSU, Lee Butler provided some specific tips about management:

“We currently recommend that everyone start their Pythium root rot prevention program off with Segway due to it being very good in our trials over the past couple of years, even at the 0.45 oz/M rate. At the 0.45 oz/M rate, you can apply Segway 6 times instead of 3 according to the label, so you will want to rotate that in with other products like Subdue, Banol, Stellar, Appear, or Signature (in no particular order). For more information about Pythium root rot, click here. Any decent Pythium fungicide such as Subdue, Segway, Banol, Stellar, Appear, or Signature (in no particular order) should do a nice job of preventing this disease. You will likely have to make repeat applications every couple of weeks until the weather changes. Rotate through the different chemistries to help with resistance management.”

Finally, don’t forget that Pythium root rot is distinct from Pythium foliar blight. The foliar (cottony) blight is actually quite rare on putting greens. Foliar Pythium is definitely linked to warmer conditions, with nighttime lows > 68. For fungicide information on foliar Pythium, you can view the table HERE from U of Kentucky (scroll to p 17).