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A Hard Winter on Bermuda

By Dr. Jack Fry and Mingying Xiang, (KSU Turfgrass Teaching, Research and Extension)

It was a hard winter for bermudagrass, and we saw extensive winter injury in Kansas – even to cultivars that we usually consider winter hardy. There is a trial at the Rocky Ford Turfgrass Research Center in Manhattan in which we’re evaluating experimental bermudagrasses from the breeding program at Oklahoma State University lead by Dr. Yanqi Wu (Fig. 1). Here are averages (of three replicated plots) of winter injury for standard cultivars included in the trial when we rated them on May 25: Tifway (100%); Latitude 36 (80%); Northbridge (75%); and Patriot (70%). The total loss of Tifway isn’t unusual, as it has poor cold hardiness. However, the severity of this winter caused severe damage to cultivars we previously thought were relatively hardy, including Latitude 36 and Northbridge. There is some good news. Several experimental grasses included in this trial experienced almost no winter injury, which bodes well for release of grasses with good cold hardiness in the future.

Fig. 1. Dr. Yanqi Qu and Mingying Xiang evaluate Oklahoma State’s experimental bermudas growing in 5 by 5 ft plots at Rocky Ford on May 25. Notice that many have extensive winter injury, while others are showing good recovery.

We heard from turf professionals in the state who indicated that injury was severe in some cases, and minimal in others – microclimates and differences in exposure likely had a lot to do with that.   Yukon bermudagrass, a seeded cultivar, had almost no winter injury at Wildcat Creek Golf and Fitness in Manhattan (Fig 2). This was impressive considering it was seeded in 2017.

Fig. 2. Yukon Bermuda, seeded in the summer of 2017 by Kevin Fateley at Wildcat Creek Golf and Fitness in Manhattan, KS showed very good recovery in May and almost no winter injury.

Fortunately, it has been a great summer for recovery. High temperatures above 100 F and lows in the mid 70s speed the growth and spread of bermuda. Unfortunately, it’s been another one of those hard summers for cool-season grasses. Here we are in Kansas trying to cope with the wrath of extreme winter and summer temperatures – been here, done this.

 

K-State resources to help you take care of trees during drought

(Megan Kennelly, KSU Plant Pathology)

Large swaths of Kansas are under drought conditions, and this week it’s only going to get worse.

We’ve talked a bit on the blog about irrigating turf, but what about our landscape trees? How can we keep them going under stressful conditions?

K-State has a set of resources to help you irrigate wisely and efficiently.

With water restrictions, it can be hard to know what to take care of first. Ward Upham provides some tips on how to prioritize watering in this week’s Horticulture News, in “Plant Triage and Watering.” 

Young trees are very susceptible to drought. They are also susceptible to overwatering! How can you get it right? Check out Watering Newly Planted Trees and Shrubs.

Older trees have more mature roots, but they can still succumb to drought.  For tips, check out: Watering Established Trees and Shrubs

Are you looking ahead to planting new trees? Keep drought in mind as a factor to consider.

 

Anthracnose crown rot in putting greens, and the turf stress behind it

(Megan Kennelly, KSU Plant Pathology)

We had a sample come in with soggy roots, algae, and a lot of thinning.

Here is the root zone. Lots of organic matter holds water, which holds heat. Hot, wet roots can decline quickly.

 

 

Hot, soggy roots can’t support growth.

(I did not find Pythium root rot structures in this sample, but these same conditions can lead to that disease, too.)

Looking closely, there was algae present. The dark green stringy stuff in the circled area is algae growing on the turf, viewed in the dissecting microscope. Algae is another indicator of wet conditions.

At closer inspection, in the compound microscope, spiny black structures were visible near the base of many declining plants that were just starting to fade from green to yellow or tan.

These structures are called setae, from the anthracnose pathogen, which is a fungus.

The publication Chemical Control of Turfgrass Diseases has a very detailed section about anthracnose, outlining many agronomic practices to reduce turf stress and reduce the threat of disease. You can find those tips at this link:

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

The anthracnose section starts on page 8.

As you glance through, you may notice that many of the practices to reduce anthracnose are similar to practices to reduce overall summertime stress in putting greens, such as providing enough but not too much water, raising mowing height (even a tiny bit can make a difference), skipping mowing and rolling instead, and maintaining adequate N. You can find the whole list starting on page 6 of Chemical Control of Turfgrass Diseases which, in short, includes information about mowing height, watering, fertility, foot traffic, dew, phytoxicity warnings, and more. We highlighted those a few weeks back in another post.

Hot + humid + rain = conditions for Pythium foliar blight

(Megan Kennelly, KSU Plant Pathology)

Here is a turf sample that came in this week. After one night in a moist chamber, there was an obvious cobwebby growth:

Notice how the turf looks matted down and greasy, too.

In the microscope here is what I saw – hyphae (fungal threads) with no crosswalls. This means Pythium foliar blight.

Pythium is not a true fungus, and many fungicides that work for other turf diseases do not work for Pythium blight. For a list of products that can handle Pythium, you can check out this resource (scroll to page 23-24):

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

In addition, don’t forget that foliar Pythium is different from root Pythium. With foliar Pythium, we see it most often in fairways, tees, and athletic fields. It is extremely rare in putting greens in Kansas. It is also rare in home lawns, but it can happen there from time to time.

Pythium loves water and lush turf. To reduce your risk, avoid over-watering and watering at night. Avoid excessive N. As a special bonus that will reduce the threat of brown patch too! Pythium can easily track with mowers and in with water-flow through drainage. Avoid mowing Pythium areas when it is wet, with mycelium, to avoid tracking it into other areas.

There are more tips here in Identification and Management of Turfgrass Diseases.

The cottony, cobwebby growth can be confused at times with brown patch. If you have any doubt, send some in to the lab.

Unlike Pythium, the brown patch fungus produces distinctive cross-walls in the hyphae:

And here is one more to show cross-walls vs none:

 

Here are some images of what Pythium foliar blight can look like in the field. You can see how it might be confused with other problems. When in doubt, send something in.

 

Tracking with a mower:

 

Not super distinctive…

…but upon closer inspection some mycelium was visible:

After a night in a moist chamber the mycelium was all over:

In the lab, that mycelium did not have cross walls.

 

Here’s one more shot of Pythium foliar blight in a low area on a bentgrass fairway:

 

Yellow Nutsedge Control

(By Jared Hoyle, KSU Turfgrass Research and Extension)

As I talk to turfgrass professionals across the state I hear that some are getting plenty of rain while others are getting none. This time of the year we think that if we are getting some precipitation we will have yellow nutsedge popping up everywhere. Well that is not always true. Yellow nutsedge does favor moist soils but it can also grow in well-drained sites.

One of the easiest ways to identify yellow nutsedge is by a couple special features;

  • erect
  • persistant
  • yellow inflorescence
  • gradually tapering leaves to a sharp point
  • tubers not in chains
  • triangular stem

To control yellow nutsedge, if you can get applications out before tuber production then you will see increased control.  But beware, yellow nutsedge will continue to grow as long as the environment is favorable for growth, so more than one application maybe necessary.

If using a herbicide application timing is critical.  During mid summer yellow nutsedge starts making tubers and if you apply herbicides before tuber production you will get better control.  If you wait until the yellow nutsedge is big and starting to make tubers then you will be playing catch-up all year. So sooner is better.  Don’t wait for it to get too big.

Here are some options for yellow nutsedge control for turfgrass professionals;

  • sulfentrazone
  • halosulfuron
  • iodosulfuron
  • mesotrione
  • bentazon
  • triflozysulfuron
  • flazasulfuron
  • sulfosulfuron

There are many different products out there that contain these active ingredients so just make sure you have an active ingredient that has yellow nutsedge control! Also make sure you check for turfgrass tolerances.

****Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application.****

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

Return of the Goathead – Puncturevine

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Return of the Goathead – Sounds like a horror movie! Well, right now I do feel like it is “Return of the Goathead”. Just about everywhere I look I see a goathead. Goathead is also known as puncturevine (Tribulus terrestris). It is a summer annual broadleaf weed that can cause headaches for many people.

 

This weed is a prostrate mat-forming weed that can produce many burs with sharp spines. This weed if invading a lawn, athletic field, playground and parks can cause injury to children and animals if they fall on or step on the sharp spines. It can also be found in disturbed areas as fields, pastures and roadsides. Good news is that many of the broadleaf herbicides are effective.

 

****Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application.****

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

“K-State to close horticultural research center near Wichita”

We learned this news last week about the J.C. Pair Center, where we conduct multiple research trials and hold extension field days:

“MANHATTAN, Kan. — Reductions in base support from the state and recent enrollment declines have led to the decision to close Kansas State University’s 120-acre John C. Pair Horticultural Center in Haysville.”

Research farm opened in 1970, focusing on woody ornamentals, turfgrass

Here is the link to the full press release:

http://www.ksre.k-state.edu/news/stories/2018/06/pair-center-closure.html

Listed on the right-hand side of that page is the contact information to share comments or raise questions:

Ernie Minton
785 532-6148
eminton@ksu.edu

 

 

 

Why is it August in June? 16 options for reducing stress in putting greens

 

(Megan Kennelly, KSU Plant Pathology)

The average daily high for June 15 in Manhattan is 86.1, and the average nightly low is 63. We have been well above those averages. Ugh! June is supposed to be our time of “things are still okay out there… July and August are around the corner, but for now we are fine.” However, this year, August is here now! Along with the heat, it is very dry out there, as shown on the most recent US Drought Monitor map:

What can you do to reduce summer stress in putting greens?

The Chemical Control of Turfgrass Diseases publication (free online!) includes an excellent list of 16 practices that can reduce summertime stress. Are you doing some of those practices already? Yes, you probably are. Are there some you are not trying? Maybe – you might test some out, or talk to your peers about what they are doing. Are some just not feasible for your site? Probably – and that’s okay. Check out the whole menu of 16 options and see if it generates any new ideas. You can find the whole list starting on page 6 of Chemical Control of Turfgrass Diseases which, in short, includes information about mowing height, watering, fertility, foot traffic, dew, phytoxicity warnings, and more.

 

With that in mind, here are some pictures to illustrate the importance of roots during stressful summer conditions:

 

KSU Turf Field Day – August 2!

(Jared Hoyle, KSU Horticulture & Natural Resources)

The Kansas Turfgrass Field Day will be held Thursday, August 2 at the Rocky Ford Turf Research Center in Manhattan.

The field day program is designed for all segments of the turf industry – lawn care, athletic fields, golf courses, and grounds maintenance. Included on the program are research presentations, problem diagnosis, commercial exhibitors, and equipment displays. There will be time to see current research, talk to the experts and get answers to your questions.

Pesticide recertification credits in 3A and 3B are available, as well as GCSAA education points.

You can register online at https://2018turfday.eventbrite.com