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K-State Turf and Landscape Blog

Author: kennelly

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.

 

Traffic and compaction

Posted on by kennelly

(Megan Kennelly, KSU Plant Pathology)

When droughty, wilting turf  is subject to traffic from vehicles, mowers, or even feet, it can develop tracks. If possible, when turf is wilty, avoid traffic altogether. If you must apply traffic, try to do it during cooler parts of the day. Sites with underlying problems like compaction are more prone to drought and therefore more sensitive to traffic.

The KSU Turf Team has several projects related to drought, management, and traffic. Want to learn more? Come out to the Turf Field Day! In addition, stay tuned to this blog for future research updates with specific results from our trials.

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We continue to see samples coming into the diagnostic lab with poor root health, but no pathogens. We got a ton of rain in May, and those root systems declined from too much water. Now that we are into the summer heat, the plants can’t thrive on those compromised root systems. Take note of problem areas, and over time you can try to alleviate compaction, change traffic flows, reduce drainage issues, etc. As much as possible, make the site function at its best to support the plants. You don’t want the site to make things more challenging than it needs to be.

Scholarship and Research Tournament – Thank You!

Posted on by kennelly

(Megan Kennelly, KSU Plant Pathology)

I’d like to give a huge thank you to everyone who participated in the Kansas Golf Course Superintendents Association Scholarship and Research Tournament.

The event was held on June 14 at Firekeeper Golf Course. Thanks to Superintendent Rob Christie, Assistant Superintendent Dan Rhule, and the crew for all their hard work getting the site ready. Thanks to Randy Towner, the General Manager and Golf Pro. Thanks to everyone else on staff for making us feel welcome.

In addition, thank you so much for the event sponsors. Here is a list from the KGCSA website showing all the sponsors for the day:

THANKS

Finally, thanks to everyone who came and participated. The funds are used to support KSU scholarships and research. The KSU Turf Team really appreciates your support!

Here are some more pictures from Christy Dipman:

Host Rob Christie:

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Mark Willmore and Cliff Dipman. Cliff runs the operations at Rocky Ford and Mark takes care of our turf research area at the Olathe research and extension center.

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A fun day was had by all!

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The case of the exploding bark

Posted on by kennelly

(Megan Kennelly, KSU Plant Pathology)

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This post’s info and photos are by Beth McKinzie, our diagnostic lab intern for the summer. Judy O’Mara, our lab director, is mentoring Beth.

The London planetree, Platanus x acrerifolia sheds its bark mid-summer in Kansas. This is a normal phase for the London planetree. A similar pattern can be observed with Sycamore trees, Platanus occidentalis which shed their bark, but not as extensively as seen on the London planetree. Both are in the same family, Platanus. There are many theories to why these trees shed there bark, which you can read about here (https://www.nycgovparks.org/news/daily-plant?id=19242). As this is a normal for these trees no management would be recommended.

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“Is this lawn still alive?”

Posted on by kennelly

Dead or alive??

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You be be getting questions from homeowners who allow their cool-season lawn to go dormant during summer but are wondering and worrying if the grass is still alive. How can you tell? How can those lawns be managed to ensure they stay alive through the dormant period?

 

This article is by Ward Upham, KSU Dept of Horticulture and Natural Resources:

Normally, a healthy lawn can stay dormant for a good 5 weeks and still recover. After the five weeks are up, it is important to keep the crown hydrated because if the crown dies, the plant dies.
Apply about 1/4 inch of water every two weeks to hydrate the crown. This will be enough to hydrate the crown but not enough to encourage weed germination and growth.
The recommendations differ for a lawn that was overwatered or received so much rain this spring so that it produced a limited root system. Such a lawn may die unless allowed to slowly enter dormancy. This is done by shutting off the water gradually. For example, instead of watering several times a week, wait a week before irrigating. Then don’t water again for two weeks. Thereafter, water every two weeks as described above.
If you are wondering if the turf is still alive, pull up an individual plant and separate the leaves from the crown. The crown is the area between the leaves and the roots. If it is still hard and not papery and dry, the plant is still alive. When rains and cooler weather arrive, the turf should come out of dormancy. However, we will probably have to deal with weeds that germinate before the turfgrass grows enough to canopy over and provide enough shade to keep weed seeds from sprouting.

(Ward Upham)

 

 

 

Trees losing leaves from summer stress

Posted on by kennelly

The following article is by Ward Upham, Dept Horticulture and Natural Resources:

 

There are three situations we may run into regarding tree leaf loss this summer.  The tree may produce yellow leaves scattered throughout the canopy of the tree, all the leaves on a tree may turn yellow and drop or the leaves may turn brown but stick to the branches.

If falling leaves are well distributed throughout the tree and result in a general thinning of the leaves, the problem is not serious.  Trees will often set more leaves in the spring than they can support during the summer. Heat and drought stress will cause the tree to lose leaves that it cannot support with the available soil moisture.  Leaves that drop are most often yellow with no discernible disease spots. However, at times, we can have green leaves drop that appear perfectly healthy.  As long as the leaf drop results in a gradual thinning of the leaves, the tree should be fine if it is kept watered during dry periods.

In some cases we may see virtually all of the leaves drop.  Certain trees such as hackberry can drop all of the leaves and enter summer dormancy. We are a bit early for this to occur but may happen later in the summer if the dry, hot weather continues.  Trees that are summer dormant should have supple twigs and healthy buds. Usually, the effect on the health of the tree is very minor and the tree leafs out normally next spring.   As long as the tree has enough stored energy reserves to make it through to next spring, it will survive.  The twigs and buds tell the story.  If the buds die and the twigs become brittle, at least that part of the tree is dead.

The last case involves trees that have leaves that die and remain attached to the tree. This can happen seemingly overnight.  In such cases, the tree couldn’t keep up with moisture demands and died quickly.  This year, the cause may be due to excessive rains this spring damaging root systems.   As in the last case, the twigs and buds are the most important clue as to the health of the tree.  As long as the buds are alive and the twigs are supple, do not remove the tree, it still has life.

If you limited ability to water and need to prioritize, trees should come first because they are the most difficult and expensive to replace.  They also take the most time to reach an acceptable size.

Last week we had a couple of articles on watering trees.  You can find those articles at: http://hnr.k-state.edu/extension/info-center/newsletters/2016/June21_2016_25.pdf  (Ward Upham)

Raise the roof! Rocky Ford rainout shelter is ready for 2016 research

Posted on by kennelly

(Megan Kennelly, KSU Plant Pathology)

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The turf team took advantage of a calm morning to raise the plastic on our stationary rain-out shelter at Rocky Ford. It takes a lot of bodies to hoist the plastic across the structure. We all got our workout for the day. Ross Braun, PhD student,will be investigating the physiology and performance of Kentucky bluegrass, tall fescue, buffalograss, and zoysiagrass under drought stress and different management scenarios (mowing height and traffic). IMG_2442 IMG_2440 IMG_2441