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K-State Turfgrass

Month: July 2014

KSU Turfgrass Student Spotlight

(By Jared Hoyle, KSU Turfgrass Research and Extension)

On behalf of the KSU Turfgrass Team, the Department of Horticulture, Forestry and Recreation Resources and the Department of Pathology, we would like to congratulate Ross Braun for passing his MS defense.  Ross’s thesis is titled “CULTURAL STRATEGIES TO IMPROVE ZOYSIAGRASS ACCEPTABILITY AND PERFORMANCE IN THE TRANSITION ZONE”.  He plans to continue his education at KSU and pursue his doctorate under the advisement of Dr. Bremer.  Ross’s doctorate project will explore nitrous oxide emissions and the use of remote sensing in turfgrass systems.  Congratulations to Ross Braun!

Ross presenting his MS seminar to the Dept. of HFRR

Non-Selective Bermudagrass Removal

(By Jared Hoyle, KSU Turfgrass Research and Extension)

For the short time I have been in the turfgrass business, I always get asked the question, “How do I kill bermudagrass?”  And before I can give the recommendation of multiple applications of glyphosate (≥ 3 lbs ae/gal) at 3 qts/A over the growing season (May, July, and September) and waiting three to four weeks for regrowth before making the follow up application, I get the response “That doesn’t work.”

To help out you can add 24 fl oz of fluazifop (Fusilade II) to the tank and it will help with bermudagrass control over the glyphosate application alone.  Remember that fluazifop has some soil residual so it can stay in the soil for some time.  So, wait 30 days before reseeding if you apply it to bare soil or 14 days if you apply it to turf. But I would still get  the response “That doesn’t work.”

Well, I got to talking with a couple of turfgrass managers about this application process and started to ask the question, “What if we are wanting to renovate during the Spring?”

Research in the past has resulted in better control with perennial broadleaf weeds, like dandelions, in the Fall compared to Spring applications. So after a little brainstorming we decided to apply this concept to controlling bermudagrass before dormancy.  This way the bermudagrass would have the dormant look throughout the winter but would be ready for renovation in the Spring.

Research Trial Location Stagg Hill (October 3, 2013)

Research was conducted at Rocky Ford Turfgrass Research Center and Stagg Hill Golf Course in Manhattan, KS to determine bermudagrass control with glyphosate, mesotrione, and fluazifop applications prior to dormancy.  Applications were made on October 3, 2013.  Treatments consisted of a non-treated control, glyphosate (6 pt/A), mesotrione (8 oz/A), fluazifop (24 fl oz/A), glyphosate (6 pt/A)+ mesotrione (8 oz/A), glyphosate (6 pt/A) + fluazifop (24 fl oz/A), mesotrione (8 oz/A)  + fluazifop (24 fl oz/A), and glyphosate (6 pt/A)+ mesotrione (8 oz/A) + fluazifop (24 fl oz/A).  All treatment included at 0.25% V/V non-ionic surfactant (NIS).  All treatments were 100% brown (dormant) bermudagrass by October 31, 2013.

Rocky Ford Trial Location (October 17, 2013)

What we found initially is that there were drastic differences between these two locations.  Bermduagrass control at the Stagg Hill location out performed the Rocky Ford location.  We believe this was due to the differences in bermudagrass cultivars.  The Rocky Ford Location was ‘Midlawn’ bermudagrass and the Stagg Hill location is a common bermudagrass.

Rocky Ford Trial Location (May 14, 2014)

At Rocky Ford the untreated control reached 100% bermudagrass cover on June 12, 2014.  At that time treatments that included glyphosate resulted in <18% bermudagrass green cover.  On June 13, 2014 the untreated control at Stagg Hill was 100% green bermudagrass cover.  All other treatments that included glyphosate resulted in <9% green bermudagrass cover.

What is really surprising is the rating that was conducted just a couple of days ago. At Rocky Ford all bermudagrass treatments recovered to at least 90% green bermudagrass cover by July 14, 2014.  But the Stagg Hill location is still showing significantly more control.  Glyphosate, glyphosate + fulazifop, glyphosate + mesotrione, and glyphosate + mesotrione + fluazifop resulted in only 27%, 26%, 17%, and 23% green bermudagrass cover, respectively.

Rocky Ford Location (June 3, 2014)

These results suggest that a single application of glyphosate in the Fall prior to bermudagrass dormancy can aid in non-selective bermuagrass removal.  We are going to repeat these trials again this year along with trying some Spring applications in combination to see if we can increase bermudagrass control.

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 http://www.facebook.com/KSUTurf

Is this brown patch?

(Megan Kennelly, KSU Plant Pathology)

Whew, it’s hot out there. We are coming up on August which is usually the peak stress time for our cool-season turfgrasses. Tall fescue lawns can start tanking this time of year, and I get a lot of samples, emails, and phone calls about brown patch.

Is this brown patch in tall fescue? What do you think? How would you figure it out?

 

So – how can you tell if it is brown patch or something else? In tall fescue, brown patch makes pretty characteristic lesions. Look for this in the areas showing decline. You might have an easier time looking on the edge of the patches instead of in the middle. Look for tan spots with a dark halo. Here are a bunch of examples: (you can click to zoom in a little bit.)

In that first stand of turf above, it was NOT brown patch.

When thinking about environmental stress there are a lot of things to consider – water (too much, too little), drainage, fertilizer, thatch, mowing practices…Take a look at this stand of turf right here:

Compaction or fill issues: This site (above) had a lot of construction activity a year or 2 ago. Construction can mean compaction from heavy equipment, backfill with less-than-optimal (to put it diplomatically) soil, and other problems. Those factors reduce root health, and then areas with reduced root function are the first to crash out when summer stress arrives.

Poor root health – I have a low area in my yard (with heavy clay soils) where water pools during heavy rains. We haven’t had heavy rains for quite awhile, but the root systems there probably didn’t grow as well. Now, those spots are showing decline while surrounding areas are looking much better.

Thatch – As one final possibility, don’t forget about thatch. Now, tall tescue is a bunch grass (lacking laterally-spreading rhizomes and stolons) but it can still build up thatch. Plus, sometimes tall fescue is planted in a blend with Kenctucky bluegrass which is more prone to thatch.

I talked about thatch not too long ago on the Facebook page. Here is some information about thatch (click the link to view).

Thatch-info

So, don’t assume you’ve got brown patch. There are plenty of other problems (even more than I listed here) that affect the health of tall fescue in summertime.

Establishing buffalograss in golf course roughs

(By Jake Reeves and Jared Hoyle, KSU Turfgrass Research and Extension)

Water restrictions and increased interest in sustainability are driving many golf course superintendents to consider new ways to save.  Ironically, one of the best new fits for saving in Kansas is one of the oldest ways around: buffalograss.  Buffalograss (Buchloe dactyloides) is actually the only widely used turfgrass native to North America. Many of the recent cultivars (Sharp’s Improved II, Bowie) grow denser and greener than their predecessors while not sacrificing their drought/cold tolerance, disease resistance, and other great characteristics. Traffic intolerance is one of the largest concerns for many superintendents, but a little traffic management can go a long way especially if coupled with cart paths. While not a perfect fit for every situation, buffalograss requires very little water, less mowing, and minimal nitrogen input to achieve an acceptable stand.

It is these characteristics that have many courses considering replacing their tall fescue roughs with buffalograss.  Once established, the courses could divert the money and time previously spent on their roughs to tees, fairways, and greens, ultimately rewarding a well-played round.

The end product is exciting for many superintendents, as their water bills would shrink. However, going through long periods of closing the course for renovations isn’t appealing to already cash-strapped courses.  Minimizing downtime and maximizing germination success with buffalograss seeding is a must if a course wanted to reduce the financial impact of the process.

We wanted to look at the most effective form of renovation from tall fescue roughs to buffalograss roughs without tilling the soil. This was to allow play to continue as long as possible on the course and keeping the renovation process very feasible for most courses.  Examining 3 different mowing heights and 4 different cultivation practices, our results will provide the most time and cost effective method for end users.

We are comparing a zero cultivation practice, aerification(2x), verticutting(2x), and slit seeding(2x @ 2lbs/M each pass)  against the 3 mowing heights (2.5”, 1.75”, 1.25”).  All cultivation practices except for slit-seeding were broadcast with Sharp’s Improved II buffalograss seed at 4 lbs/1000 ft2.  Traditionally, it is recommended that buffalograss seed be soaked for 3 days, changing the water every day, to encourage a quick germination upon seeding.  However, we did not soak the seed, believing the process not to be practical if a course was truly reseeding all of their rough.

Our results to date have shown that slit-seeding was the most successful method by far with aerification, verticutting, and zero cultivation decreasing in effectiveness in that order.  Slit-seeding mowed at 1.25” and 1.75” reached 100% cover 6 weeks after seeding (WAS) with minimal weed encroachment.  Ultimately, mowing height has had no effect except for a very slight lag in plots mowed at 2.5” compared to the two lowers heights. We hope to continue looking at fescue removal and buffalograss seeding in order to shorten the green cover loss experienced in the renovation process.

Walnut Caterpillar

(By Dr. Ray Cloyd, Dept. of Entomology)

We have seen an “explosion” of the walnut caterpillar (Datana integerrima) in several portions of Kansas. Walnut caterpillar feeds on the leaves of walnut, pecan, hickory, and may also feed on birch, oak, and apple. The larvae tend to feed in groups/clusters consuming all leaves on a single branch before moving to another branch to devour leaves. Excessive defoliation may result in sunscald that could weaken trees and increase susceptibility to wood-boring insects. Walnut caterpillar overwinters as a pupa that is located beneath the soil surface under a host tree. Adults are robust moths that emerge from pupae in mid-to-late spring, depending on temperature and host plant growth. The brown forewings possess irregular dark cross lines. Females deposit eggs on leaf undersides with each female capable of laying >300 eggs in a mass. The first instar larvae or caterpillars skeletonize leaves, whereas the second instar larvae feed on the entire leaf with the exception of the mid-vein. The later instar (third and fourth) larvae, which are red in color, feed on the entire leaf including the petiole. Larvae feed for approximately one month before reaching maturity. Full-grown larvae are 2.0 inches in length, with yellow stripes on the side, and are gray-black and covered with long, gray to white hairs. When disturbed, larvae will arch their head and the end of the abdomen in order to ward off predators. When it is time to molt, they all gather together on a branch or trunk and molt simultaneously, leaving patches of fur-like hair. There may be one to two generations per year. The primary effective means of dealing with infestations of walnut caterpillars are to hand-pick caterpillars and place in a container of soapy water, use a forceful water spray to quickly dislodge caterpillars, or apply insecticides with one of the following active ingredients: acephate, spinosad, malathion, cyfluthrin, permethrin, or bifenthrin. Although the eggs and larvae of walnut caterpillars are susceptible to parasitoids, the female parasitoids may not attack enough eggs or larvae to substantially impact the population.

Author:

Raymond A. Cloyd

Professor and Extension Specialist in Horticultural Entomology/Integrated Pest

Management

Department of Entomology

Kansas State University

123 Waters Hall

Manhattan, KS 66506-4004

Phone: (785) 532-4750

Email: rcloyd@ksu.edu