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K-State Turfgrass

Month: June 2016

Scholarship and Research Tournament – Thank You!

(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:

2016S&R_Host_Christie

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.

2016S&R_KTFTeam

A fun day was had by all!

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2016S&R_3

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The case of the exploding bark

(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?”

Dead or alive??

drought-stress

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

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

(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

 

HOT! Soil temps and turf decline

(Megan Kennelly, KSU Plant Pathology)

We all know it has been super hot lately. Yuck! We humans are suffering because of the hot air, but our cool-season turfgrasses are suffering from the high soil temperatures.

I have not had an onslaught of samples yet, but I fear that if this weather keeps up, they will be coming soon. Usually the flood of turf comes in August, but this is shaping up to be a tough year. (If we are lucky, I’ll be wrong and the weather will chill out, the turf will chill out, and WE can chill out!)

I took a look at soil temperatures at the Kansas Mesonet website (click HERE to access it), and I saw that our 2-inch daily max soil temps in Manhattan have been soaring into the 90’s and our 4 inch daily max soil temps have been solidly in the mid to upper 80’s.

Pop quiz – do you remember the optimal 4-inch soil temperature range for root growth in cool-season turf?

Got your guess?

The answer – 50-65 degrees Fahrenheit. We will not be seeing that again for several months.

When we get into our current range of steamy 80’s and 90’s in the soil, root growth shuts down. Shoot growth is shutting down too. That means, if you lose cool-season turf now it will be very hard to get it back again.

Now, I’ll point you to some prior posts and references that outline some tips on summer stress management.

We sent these two last week, but I’ll post again here.

By Jack Fry: - general tips for water management:

https://blogs.k-state.edu/turf/good-water-management-will-help-get-greens-through-midsummer-stress/

By Dale Bremer - using moisture sensors:

https://blogs.k-state.edu/turf/water-management-on-greens-with-soil-moisture-sensors/

 

Here is another old post from last year:

Summer weather can be ruthless when the turf is stressed and rootless

And, finally, in this page, starting on page 6, there is an excellent, clearly-written set of tips on reducing summer stress in putting greens. Really – if you manage putting greens, take a couple of minutes, click here, scroll to page 6, and read these tips.

http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf

 

 

 

That’s not a disease! (Lacebugs on cotoneaster)

(Megan Kennelly, KSU Plant Pathology)

Brown spots are not always a disease.

We had a cotoneaster sample last week that looked like this:

damage-lacebug

The undersides of the leaves looked like this:

lacebug-frass-cotoneaster-branch

The submitter thought this might be a disease, but upon closer inspection we found these guys, lacebug nymphs. The shiny black stuff near them is frass (insect poop).

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Lacebug eggs:

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But, what else did we find?

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This is a laceWING egg. Lacewings are predators (good guys!), and they love to eat lacebugs!

I called my awesome colleague Dr. Raymond Cloyd to discuss this, and he confirmed that in general, lacebugs will not severely damage the plants. The damage is primarily aesthetic. And, the good guys (lacewings) were clearly in the area, doing their job. Dr. Cloyd’s advice was to let nature take its course. One “soft” option might be a hard spray of water to remove/reduce the lacebugs. That would also remove the lacewings, but the lacewings would come back.

Lacebugs (and many other insects!) are described in our publication: Tree and Shrub Problems in Kansas: Diseases, Insects, and Environmental Stresses. To get a copy of that publication, you can find the pdf HERE or you can order it by calling the K-State Research and Extension bookstore at 785-532-5830 where you can order a print copy for $9.70 + shipping.

 

 

 

 

Pythium foliar blight in ryegrass and bentgrass tees and fairways

(Megan Kennelly, KSU Plant Pathology)

I haven’t received any Pythium foliar blight samples yet, but I wanted to provide a heads up and reminder.

Pythium foliar blight, sometimes called cottony blight, is one of the most destructive turfgrass diseases.  The disease can explode in only a few days if conditions are right. Perennial ryegrass and tee- or fairway-height creeping bentgrass are the most common hosts in Kansas. Though Pythium root rot (caused by different species) is common in putting greens, Pythium foliar blight is rare in putting greens. In 10 years, I have seen it only ONE time on a putting green. Tall fescue, Kentucky bluegrass, bermudagrass, and zoysiagrass can become infected, but this is extremely rare.

Conditions for Disease Development

The risk of Pythium blight is highest during humid weather when day temperatures are 86 to 95 degrees Fahrenheit and overnight lows are consistently at least 68 degrees Fahrenheit.

The disease is most common when soils are saturated with water, due to excessive rainfall or irrigation. Long dew periods, high relative humidity, and lush, dense turfgrass growth also favors disease development. Low areas, sites with poor air flow, and sites with poor drainage are particularly vulnerable.

Symptoms

In fairway-height bentgrass and perennial ryegrass, the first symptoms are irregularly shaped, water-soaked, greasy patches up to 4 inches in diameter.

Pythium in rye fairway

If it is humid, a cottony growth may be present early in the morning.

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The patches may merge into larger blighted areas.

pythium 2006-2

The pathogen can be spread by equipment  and in water drainage patterns. Here is some Pythium blight at Rocky Ford a couple of years ago, following the pattern where heavy rain caused a water flow across this plot from left to right.

r ford pythium blight

Look-alikes: Pythium blight can be confused with brown patch, damage due to thick thatch, drought stress, or grubs. Brown patch is active during these same conditions. If you have any doubt, you can always send a sample to the diagnostic lab.

Management

Pythium thrives in water, so water management is the key to Pythium blight control. The following practices will reduce the risk of other diseases (and stresses), too:

  • Improve drainage in areas where water is likely to stand for any length of time.
  • Avoid overwatering, especially during hot, humid periods.
  • Promote rapid turfgrass drying by proper spacing and pruning of shrubs and trees.
  • Fans can improve airflow in closed-in areas where collars and approaches have a history of disease.
  • Irrigate in the early morning to reduce the number of hours of leaf wetness.
  • Excessive nitrogen fertilization stimulates lush growth that is more susceptible to Pythium blight. Maintain a proper balance of nutrients and avoid fertilizing during periods of Pythium blight activity.
  • If active mycelium is present, avoid mowing, which can spread the pathogen.

Preventive fungicide applications during the summer months may be necessary on perennial ryegrass or creeping bentgrass golf fairways.

Below is the Pythium blight fungicide information from Chemical Control of Turfgrass Diseases by Paul Vincelli and Gregg Munshaw at University of Kentucky. You can click the image below to zoom. For the full guide, visit HERE.

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