Virginia Turfgrass Journal - July / August 2015

Prepping Bermudagrass for Fall/Winter to Reduce Potential Winter Injury

Virginia Turfgrass Council / P.O. Box 5989 / Virginia Beach, VA 23471 / ADDRESS SERVICE REQUESTED

Organic Amendments

for Turfgrass and Other Urban Landscapes

Measuring the Accuracy and Precision of

Ball-Roll Devices

Journal of the Virginia Turfgrass Council | July/August 2015

12 11 Upcoming Event

2015 VT Turfgrass Field Days in Blacksburg, August 25–26

12 Cover Story

Prepping Bermudagrass for Fall/Winter to Reduce Potential Winter Injury

16 Turf Basics

Organic Amendments for Turfgrass and Other Urban Landscapes

20 Applied Research

Measuring the Accuracy and Precision of Ball-Roll Devices

22 Research Report

PoaCure (Methiozolin) for Kentucky Bluegrass Population

24 Research Summaries

Confirming Glyphosate Resistance in an Annual Bluegrass Population Creeping Bentgrass Response to PoaCure, Proxy and Cultivation

16 Departments 06 President’s Message

from Fred Biggers, CGCS

08 Director’s Corner

from Tom Tracy, Ph.D.

9 Editor’s Perspective

from Mark Vaughn, CGCS

10 VTF Report from Betty Parker 26 Turfgrass Calendar 26 Index of Advertisers Virginia Turfgrass Council (VTC) serves its members in the industry through education, promotion and representation. The statements and opinions expressed herein are those of the individual authors and do not necessarily represent the views of the association, its staff, or its board of directors, Virginia Turfgrass Journal, or its editors. Likewise, the appearance of advertisers, or VTC members, does not constitute an endorsement of the products or services featured in this, past or subsequent issues of this bimonthly publication. Copyright ©2015 by the Virginia Turfgrass Council. Virginia Turfgrass Journal is published bimonthly. Subscriptions are complimentary to members of VTC. POSTMASTER: Send change of address notification to VTC, P.O. Box 5989, Virginia Beach, VA 23471. Postage guaranteed. Third-class postage is paid at Nashville, TN. Printed in the U.S.A. Reprints and Submissions: Virginia Turfgrass Journal allows reprinting of material published here. Permission requests should be directed to VTC. We are not responsible for unsolicited freelance manuscripts and photographs. Contact the managing editor for contribution information. Advertising: For display and classified advertising rates and insertions, please contact Leading Edge Communications, LLC, 206 Bridge Street, Franklin, TN 37068-0142, (615) 7903718, Fax (615) 794-4524. Deadlines are the first of the month prior to the following month’s publication. (Example: August 1 for the September issue.)

Virginia Turfgrass Journal is the official publication of The Virginia Turfgrass Council P.O. Box 5989 Virginia Beach, VA 23471 Office: (757) 464-1004 Fax: (757) 282-2693 vaturf@verizon.net Published by Leading Edge Communications, LLC 206 Bridge Street Franklin, Tennessee 37064 (615) 790-3718 Fax: (615) 794-4524 Email: info@leadingedgecommunications.com Editor Mark Vaughn, CGCS VTC OFFICERS President Fredrick Biggers, CGCS Wintergreen Resort (434) 325-8252 Vice President Rick Owens, CGCS Laurel Hill Golf Club (703) 674-6934 Treasurer Scott Woodward Woodward Turf Farms (540) 727-0020 Past President Frank Flannagan msg1sg@verizon.net (804) 356-1535 VTC DIRECTORS Tony Montgomery Marc Petrus Jesse Pritchard Christian Sain Michael Skelton Rick Viancour, CGCS Jimmy Viars, CGM Brian Walker ­ VTC ADVISORY MEMBERS OF THE BOARD Mike Goatley, Ph.D. (Chair) Shawn Askew, Ph.D. Jeffrey Derr, Ph.D. Erik Ervin, Ph.D. David McCall Executive Director/ Director of PROGRAMS Tom Tracy, Ph.D. (757) 464-1004 Virginia Turfgrass Foundation Betty Parker (757) 574-9061

Journal of the Virginia Turfgrass Council

|5

President’s Message

Lots of

Happenings Ahead!

Fred Biggers, CGCS • VTC President

Well,

it’s that time of the year again, with summertime in full swing as you read this column. As far as being able to produce good playing conditions on the turf we manage, most of our success comes from all of the work done previously — this past spring’s aerifications, topdressing, fertility programs, weed control, etc. We need to approach our professions exactly the same way. The more we expose ourselves to the latest turf research findings by attending one of the excellent Virginia Tech Field Days, the better we prepare ourselves to react to the constant changes that the weather throws at us in our struggle to improve our golf courses, sports fields or landscapes.

This year, if you missed the Field Day event at the Hampton Roads AREC on June 23, be sure to attend the August 25–26 Turfgrass Research Field Days in Blacksburg on the VT campus.

The next big news to share is that the VTC Board of Directors voted to move the VTC’s Bob Ruff Jr. Memorial Research Golf Tournament to midSeptember to schedule it away from other fundraising tournaments that are so popular in May and June across the state. We have rescheduled the event for Monday, September 14, at Wintergreen Resort’s Devils Knob Course. Once again, we will host three different Craft Breweries for your enjoyment, along with cool, delightful temperatures up at 3,500 ft. of elevation.

This will also give players a chance to play Devils Knob, which is a beautiful, challenging course that will be

6 | Virginia Turfgrass Journal July/August 2015 www.vaturf.org

fun to play in the “captain’s choice” format.

Next winter’s new Mid Atlantic Turfgrass Expo (M-AT-E) event will be coming up before we know it! It’s scheduled for January 25–28, 2016. You will notice an expanded tradeshow area with more vendors than ever before, and it will also feature an expanded conference program. Co-chairs of the Program Committee, Dr. Mike Goatley (Virginia Tech) and Dr. Tom Turner (the University of Maryland) are hard at work finalizing the many details of a multi-track conference program. Recently, we had some exciting news that Mr. Pat Jones — a wellknown turfgrass media personality — will be assisting in several areas of M-A-T-E planning.

Finally, work continues on the VTC’s new Certified Turfgrass Professional program. Mr. Jimmy Viars, CGM, is now chairing the new CTP Committee for the VTC. It is our hope that this program continues to grow in numbers and recognition over the next several years. Much hard work by Dr. Tom Tracy and Dr. Mike Goatley went into this program, and I think it offers a real opportunity for so many turfgrass professionals to expand their knowledge and get some genuine recognition for their achievement.

As always, it continues to be my great pleasure to be involved with the VTC. I hope you can take the opportunity this summer to get away to enjoy the VT Field Day, and to enjoy the camaraderie offered by your fellow turf professionals. c

Director’s Corner

In Memory of an Industry Friend Tom Tracy, Ph.D. • VTC Executive Director

When

Dr. Rajandra Waghray passed away on May 2, 2015, our industry lost a dear friend. Many of us have fond memories of Raj and the guidance he provided the turfgrass industry. Throughout his decades of service, he epitomized the phrase “gracious leader.” He was a leader because of what he did. He was gracious because of who he was.

During his tenure with the Virginia Cooperative Extension Service in Fairfax County, Raj initiated and managed the Fairfax County Gypsy Moth Control program and established Neighborhood Plant Clinics, the Plant Diagnostic Laboratory and the Agriculture Information Center. Throughout his service, Raj received many awards, including three from the Virginia Turfgrass Council: Lifetime Membership (2004), President’s Award (1999) and the VTC Award (1996).

Raj’s graciousness may be illustrated in many ways and by many persons, but allow me to present a personal example. I first met Raj (even now, I have difficulty using his full name since he always insisted we use his nickname) nearly four decades ago when he interviewed me for a position in northern Virginia. Long story short; I did not get the job.

But now, consider what happened in the early 2000s when the Virginia Turfgrass Council brought me aboard as executive director. Raj was very active on the board of directors as a technical and education advisor and was instrumental in the VTC’s decision to hire me. After some months into the job, I reminded him of our first meeting. Graciousness flowed through his answer: “Oh, Tom, that job was not good. You are fortunate it was not for you.”

Virginia’s turfgrass industry owes a tremendous debt to Dr. Rajandra Waghray. He will be missed. c

Dr. Rajandra Waghray (right) accepts the 2004 VTC Lifetime Membership Award from Robert Barksdale (then, chairman of the VTC’s Nominations & Awards Committee).

8 | Virginia Turfgrass Journal July/August 2015 www.vaturf.org

Chances Are…

Editor’s Perspective

Mark Vaughn, CGCS • Virginia Turfgrass Journal Editor

I

hate The Weather Channel. I realize the Good Book says we are not supposed to hate, but I can hide my true feelings no longer.

It’s nothing personal. Unless you count Jim Cantore. Okay, how ‘bout dislike?

That’s more PC, I guess, although I find that folks are using stronger adjectives than ever to describe people, organizations, thoughts, THINGS they don’t agree with. Just read the online comments of keyboard jockeys about politicians, artists, musicians, corporations, policemen, school systems, athletes, scientists, you name it. We’re mighty dang mad and bad#$$, hiding behind our fake user names and our cute little avatars.

So, you may ask, what about Jim and the gang has this old redhead so fired up?

Remember when The Weather Channel started? It was a bare-bones, show-me-an-old-bald-headed-nerdymale-meteorologist-standing-in-frontof-a-map-delivering-the-facts (just the facts, ma’am) station. Then, every five minutes or so, they would give you the forecast. Over and over and over. While I appreciate the transition from nerdy males to shapely attractive females as the delivery system, the… excuse me, The (I guess that’s like THE Ohio State University) Weather Channel has morphed into the meteorological version of VH1.

Whereas once VH1 actually played music and now plays NONE, The WC has transitioned to soap-opera climatology. What’s with this crap of naming every weather system now? “Wooooo… here comes winter storm THOORRRR. I don’t know how this isn’t going to wipe out half the population of Boston, Al.” “You’re so right, Stephanie, fresh off that one-two punch of Remus and Sparta, there’s no way Beantown can keep from sliding into Boston Harbor!”

Throw in the “It Could Happen Tomorrow!” “Full-Force Nature” and “Storm Stories” silliness, and you’ve

just about got Berta and ol’ Fred whipped into a frenzy. “Better go down to the storm cellar and freshen up the supplies. It’s a whole two miles to the nearest Wally World. Don’t want to be stranded out here in the boonies with no Cheez Whiz.”

But, that’s not why I ha… dislike The WC so much. The Weather Channel has access to over 100 million cable and satellite subscribers. With the internet and all of its connectivity prongs, plus mobile devices, Jim et.al. have access to pretty much anyone on the planet.

So WHAT, you say? What I say is that’s a lot of power and influence. Take, for instance, what happened at our course this week. What currently has my blood pressure up is that we’re in day two of a supposed four-day continuous rainy period. Except, it didn’t rain yesterday, and it’s not raining today. And it’s 82 degrees. In late May. In an industry that desperately needs customers and didn’t see hardly any 4th quarter 2014 or 1st quarter 2015, except for the few days day The WC gloom and doomers said it might actually be a NICE day to get outside. But, do you think we had more than a handful of golfers on these cloudy but pristine days? Guess they must be the ones that didn’t cut on the boob tube.

All I’m asking for from The WC is a little perspective. For example, rather than saying, “There’s a 40 percent chance of rain today,” how about, “Odds are, it’s not going to rain”?

And instead of putting the raindrop icon on any forecast day when there is ANY chance of rain, how about only if it’s 70 percent or above? Instead of, “The weekend looks pretty much like a washout,” maybe something like, “We have less than a 50/50 chance of knowing what’s going to happen five days from now. Just depends on where the dart sticks.” But then, that wouldn’t build the anxiety or get the adrenaline flowing.

I’m sure the milk-and-bread people love WC. But other than those, think about this for a minute. What if the non-weather-related businesses had to fight this kind of negative publicity?

What if, when you went to a restaurant, there was some guy outside reminding you, “Conditions may not be ideal.

There’s a 20 percent chance the meat locker is not between 33 and 37 degrees.

And remember that lettuce and E. coli thing.” At the movies — “This film got terrible reviews. Plus, it’s probably going to be cold in there.” At the gym — “All kinds of hazards beyond those doors.

30 percent chance you could twist an ankle or pull a muscle. Might want to reconsider.” What if at the airport, there was a continuous loop of near misses, hijackings, crashes and other lowpercentage happenings on all the overhead monitors? Getting the idea?

I’m convinced that if ol’ Lee Kinard was still on Channel 2, standing beside his hand-drawn weather map, reading the forecast ONCE every 30 minutes during the one-hour newscast in the morning and ONCE during the halfhour nightly news, versus 24-hour gloom and doom, I’d have had 60 to 70 more golfers each of the past two days. They’d just wait until the day of, walk out the door, see that it’s not raining and hope for the best. Instead, multiply that 60 to 70 by numerous days each season, and you can see why just one time I’d like to see a wind gust pick up Cantore, slam him into the nearest wall and knock that microphone out of his hand.

Besides, in what other profession can you overpromise and under-deliver as consistently and still have a job?

Hmmm… come to think of it, maybe The WC is hiring. c Journal of the Virginia Turfgrass Council

|9

VTF Report

Why We’re Here —

For You Betty Parker • VTF Manager

It

is inconceivable to imagine an orderly workplace without first entertaining what might be done to improve it. You can’t create a better situation, improve a method, hone a more efficient schedule or realize a more desirable existence without making a few mistakes along the way. If you are sincere in your purpose, you can eliminate some of the more obvious pitfalls (or at least never repeat one that you already experienced). You gravitate toward an intelligent guess and then carefully proceed. In the words of Hemingway, “Isn’t it pretty to think so?” And, yet, this is exactly what we are trying to do.

The VTF is challenged to support, encourage and fund research that will make your turf more tolerant to disease and drought. We want it easier and less expensive to maintain, aesthetically appealing and indestructible to the wear and tear of its desired use. Our first priority is to identify your concerns for the turf you maintain. We need you, the turfgrass industry members, to let us know what you are scratching your head about. We encourage and favor research that is innovative, cutting edge and, most importantly, pertinent to your needs: so, we need your input. What problems, concerns and questions do you want addressed in the research you fund?

Often, the turfgrass team at Virginia Tech already knows what you are pulling your hair out over. They entertain your questions at symposiums across the state, at conference sessions and via telephone calls. They are relentless in being your public servants, and they are sincere in their efforts. We are so fortunate to have our turf team at Virginia Tech. They work well with one another, and the respect they

command from other professionals around the nation and world allows them to collaborate with the very best.

They don’t duplicate their research — they enhance it. They don’t repeat mistakes, they shift gears, and they make it better for you. The VTF is entrusted with finding the funds to support that research.

The VTF is empowered by a board of directors represented by all facets of the turf industry. We have set up an endowment fund through the collective efforts of all represented in this industry. Our goal is to grow the endowment to one million dollars before we begin harvesting the interest for its intended use of funding turfgrass research. We have recently tipped the scales in moving toward that goal and are now watching the exponential growth of this unencumbered treasure. In a few more years, we will recognize its fruits in the form of substantial increases in the research dollars we provide for turfgrass research.

Currently, a major portion of the dollars we use to endorse our research is realized through the Virginia seed law fund that the turfgrass industry was instrumental in setting up in 1992.

This fund, collected through the taxes and licensing of seed purchased in Virginia, currently provides between $40,000 to $70,000 each year for this research. In a few years, with the addition of the endowment fund interest, we hope to double the research support we provide each year.

contributor, but we are also supported by the proceeds of the annual Bob Ruff Jr. Research Golf Tournament. This tournament provides an average of $10,000 to turfgrass support. This year’s tournament will be held at Devil’s Knob at Wintergreen Resort on September 14.

Royalties from Mohawk seed, a bermuda blend that Drs. Schmidt and Taylor developed, provide an average of $5,000 for turfgrass research. We are currently looking at expanding our royalties program to include other varieties of seed that are being used in the state.

But our largest pot of gold is YOU, the turfgrass industry. In recognition of the work the VTF does, you dig deep each year and award your industry with a brighter tomorrow. YOU, the individual, the local turf organizations (such as the Shenandoah Valley TA and the Virginia TA), the statewide associations (such as the Virginia Sod Growers and the Virginia Sports Turf Managers Association) help support turfgrass research here in the state of Virginia. It is all of us working together that allows us to fund this research.

Never underestimate the importance you play individually in this monumental task. If YOU are a part of Virginia’s turfgrass Industry, YOU are a part of the VTF. The VTF thanks all of you for the piece of the puzzle you provide in realizing the dollars it requires to recognize and attain our mission:

How have we been able to raise the funds for the endow- ment and the yearly support we provide for the research?

The mission of VTF is to develop funds to support and promote research, education and Extension programs in the management and science of turfgrass and its related environment in Virginia. c

The seed law fund has been our biggest

This article is dedicated to the memory of Dr. Rajandra Waghray (December 4, 1938 – May 2, 2015).

10 | Virginia Turfgrass Journal July/August 2015 www.vaturf.org

Cover Story continued

Upcoming Event

2015 Virginia Tech Turfgrass Field Days August 25–26 in Blacksburg, VA Back from Last Year — Tuesday Symposium and Pesticide Recertification!

TUESDAY (AUGUST 25)

WEDNESDAY (AUGUST 26)

Turfgrass Symposium Includes Pesticide Recertification: Categories 3A, 3B, 10 and 60 Southeast End Zone Suite, Lane Stadium (pick up parking passes outside the stadium).

PART ONE

8:00 a.m. – 8:30 a.m.

Sign-In and Registration

Turfgrass Center (off Southgate Dr.)

7:30 a.m. – 8:00 a.m.

Registration

10:00 a.m. – 11:00 a.m.

Travel (use your own vehicle)

8:00 a.m. – 8:15 a.m.

Opening Remarks

11:00 a.m. – 12:00 p.m.

Lunch

8:15 a.m. – 10:00 a.m.

Research Tours

12:00 p.m. – 12:30 p.m.

Announcements 12:30 p.m. – 2:30 p.m.

Tours

8:30 a.m. – 11:30 a.m.

Legal Matters, Mole and Vole Control and Updates on Disease, Insect and Weed Control Program 11:30 a.m. – 1:00 p.m.

Lunch (on your own) 1:00 p.m. – 4:30 p.m.

Cultural Management Programs to Reduce Pesticide Inputs; Hands-On Demos of Spray Equipment and New Nozzle Technology; and a “Weed Walk” 5:30 p.m. – 8:00 p.m.

Q&A Session and Spuds & Suds Social Home of Dr. Mike Goatley NEW ADDRESS — 2010 Scott Drive Blacksburg, VA 24060

PART TWO

Glade Road Research Facility

3:00 p.m.

Adjourn

Pricing and Registration Tuesday (August 25) Symposium and Pesticide Recertification for VTC Members................FREE Symposium and Pesticide Recertification for Non-VTC Members...........$30 Q&A, plus “Spuds and Suds”....................................................................FREE

Wednesday (August 26) Demos, Research Tours and Lunch............................. $45 for VTC Members Demos, Research Tours and Lunch...................... $60 for non-VTC Members Attend and Renew/Join the VTC................................................................. $95

Photo on this page by Tony Montgomery.

Journal of the Virginia Turfgrass Council

| 11

Cover Story

Prepping s s ra g da u Berm r e int w / all f for al Winter Injury to Reduce Potenti

By Mike Goatley, Ph.D., Extension Turfgrass Specialist; Erik Ervin, Ph.D., Turfgrass Physiology; Shawn Askew, Ph.D., Turfgrass Weed Specialist; and David McCall, Turfgrass Pathologist, Virginia Tech

The

Virginia Tech turfgrass team has long been a strong proponent of bermudagrass for athletic fields and golf fairways because there simply is not another grass available to us that produces as much canopy density and recuperative potential as bermudagrass for heavily trafficked turfs. However, let’s consider what we hopefully have learned/observed from the challenges of these past few years that can apply to trafficked bermudagrass turf for this fall and beyond.

Looking back… what we’ve learned

There are no absolute guarantees of survival, but the genetics of the improved “cold-tolerant” bermudagrasses have come to the forefront in Virginia’s recent winters. Varieties such as Latitude 36, Northbridge and Patriot (all vegetative) and Riviera, Yukon and Sovereign (typically seeded) continue to demonstrate their cold tolerance.

Has there been damage to these grasses? Yes. For the first time in memory, there was significant loss of

12 | Virginia Turfgrass Journal July/August 2015 www.vaturf.org

Patriot athletic fields in northern Virginia in winter 2013–2014, but the level of turf loss was not consistent statewide, and damage was not catastrophic in most locations (more on the possible contributing factors to turf losses below). The winter of 2014–15 saw damage mainly from Richmond to Tidewater, with the rest of the state generally coming through the winter in pretty good shape with their bermudagrass because there was significant snow cover during the coldest days of late February when many locations

had sub-zero nighttime lows.

Extreme cold without the insulating effects of snow cover was definitely a major factor in the scope of winter damage in the winter of 2013–2014.

However, other contributing factors are always at play in the occurrence of winter kill. For the winter of 2013–14, there did not seem to be a consistent pattern where typical problem situations (such as poorly drained soils, shade lines, or aspect) led to increased winterkill; as many times as not, the grass survived on these typically problematic situations, and it performed poorly on drier, sunnier, westernfacing slopes. In the winter of 2014– 15, the winter damage did seem to more closely parallel all the common problems previously detailed. And any time you pair two or more of these situations together, the level of winterkill gets further exaggerated. In particular, winterkill on golf courses with the shade from tree-lined fairways was very widespread in 2014–15 in eastern Virginia and central North Carolina (Photo 1).

Turf blankets definitely enhanced winter-survival characteristics of bermudagrass on athletic fields. There is significant expense in their purchase, as well as labor for their installation and removal, but if protection of the bermudagrass field is a priority, then we have no better way to improve our chances of surviving a difficult Virginia winter than by covering it with a blanket. The blankets not only offer protection for the bermudagrass, but also they can be beneficial in enhancing ryegrass-overseeding development.

Is winter protection absolute with a cover? Unfortunately, no. Year after year, however, the “spring cover line” distinction between covered and uncovered turfs is very evident as to the value of the blanket in winter protection and accelerated spring greening.

The value of covers for the winter protection of the ultradwarf bermudagrass research green at the Country Club of Virginia in Richmond is evidenced in Photo 2. If properly stored, standard turf blankets should easily last 10 or more years in most situations, so their cost really isn’t prohibitive

if you consider price of re-grassing a field if it is lost to an extreme winter.

Overseeding with ryegrass, while a necessity for many situations because of the need for an actively growing, green playing surface for the spring season, definitely reduced bermudagrass recovery in both springs of 2014 and 2015. However, several managers indicated they thought that the ryegrass overseeding might have actually benefited the bermudagrass survival in February 2015. The thinking is that the ryegrass canopy provided additional low-temperature protection. Each of us can say that we have seen this occur sporadically over our careers, but in general, the competition from the ryegrass typically works against you, rather than for you, in spring and summer bermudagrass quality (Photo 3). Many turf managers who enjoyed what was an outstanding overseeded playing surface in early spring were dismayed to find very little bermudagrass remaining underneath that ryegrass canopy when they later removed the cool-season grass with a chemical transition aid (such as one of the sulfonylurea herbicides). Our “takehome message” about overseeding is this: it is not an agronomic decision, but is instead an economic decision.

If the economics of your situation justify overseeding, then overseed, and do it well.

We also are starting to see occurrences of resistance to sulfonylurea herbicides on area athletic fields (for example, annual bluegrass on sports fields in Culpeper and perennial ryegrass on Worsham Field at Virginia Tech). So, be aware of this for the future if you have been on a regular SU-based ryegrass-removal program.

Resistance problems are definitely in play, and when/if possible, a change in chemistry mode of action is warranted.

Looking forward… what we know can help

One consistent contributor to dead or damaged bermudagrass turf does return year after year: intensive fall traffic. Anything that can be done to distribute traffic (rotate goals on soccer fields, move practice drills around

for football, alter entrance and exit points into/out of fairways and green complexes) will greatly improve survival. Similarly, any mechanical cultural practices (coring, solid tining, etc.) that can be done to reduce compaction in these areas are beneficial. Schedule cultivation in these trafficked areas as best you can around play. However, probably the most important thing that can be done is to distribute the traffic around the site, if at all possible.

Continue mowing regularly for the rest of the summer, and keep blades sharp. Many turf managers notice that bermudagrass mowing quality declines from mid-summer forward, and a reason for this is a change in the plant’s morphology due to shorter day lengths.

The grass starts to grow more “upright” than “lateral.” Plant growth regulators (such as trinexapac ethyl and trinexapac ethyl + flurprimidol) can enhance mowing quality and reduce cutting requirements, as well as improve lateseason wear tolerance and overseeding grass establishment later this fall if the PGRs are used as part of a regular program (i.e., a single application of the PGR is of very little benefit).

Another strategy successfully employed with bermudagrass is to use the PGRs up until a few weeks before the first anticipated frost and then allow the bermudagrass to “rebound” one last time after the PGR applications cease. Keep in mind that different varieties of bermudagrass demonstrate different tolerances to PGRs, so be sure to pay attention to label recommendations, and/or talk to your peers about their experiences with various rates of PGRs on their bermudagrasses.

Don’t get greedy with your cutting height. One of the strengths of bermudagrass is its ability to perform and play so well at relatively low cutting heights (less than 1”). However, don’t keep those heights where they CAN be kept going into dormancy, but instead, consider where they SHOULD be kept as the grass goes into winter dormancy in order for it to better withstand possible extreme weather conditions.

Raising those heights by 0.25" to 0.5" BEFORE the onset of dormancy can Journal of the Virginia Turfgrass Council

| 13

Cover Story

1 Photo 1. The difference in winterkill of this bermudagrass fairway is distinctly highlighted between the center of the fairway and the shaded rough that separates the holes.

Photo 2. The value of a turf blanket in the protection of the ultradwarf bermudagrass putting green trial at the Country Club of Virginia is evident in this photo.

Photo 3. The non-overseeded bermudagrass area to the right of this bermudagrass playing field has much greater spring density than the overseeded playing surface to the left.

2

3

be the difference between living and dead turf.

Do you have current soil test results?

If you have not conducted a soil test for the past three years, it is time to do so once again. Soil test in mid-late summer so that you can adjust pH, P and K levels prior to dormancy. The bermudagrass still has several weeks left to respond to lime and nutrient adjustments before winter arrives.

Continue to feed the bermudagrass while it is actively growing. The updated Nutrient Management Standards and Criteria from the Virginia Department of Conservation and Recreation allows for up to 0.7 lb. N per 1,000 ft2 per growing month for water-soluble N sources, and up to 1 lb. N per 1,000 ft2 per growing month for slowly available N sources (defined as any N source with ≼ 15% WIN or SAN).

Pre-emergent herbicides for this fall on bermudagrass fields and fairways: would you or wouldn’t you? On your most heavily trafficked areas, almost all PRE herbicides we use in Virginia have concerns with turf recovery, and certainly so with any potential need for reseeding or resprigging that might arise. The duration and completeness of weed control with one of the more recent PREs to enter the bermudagrass market, indaziflam (Specticle), is phenomenal, but its use seems best suited for lower-trafficked golf turf situations and definitely not on heavily trafficked sports fields. If you are interested in using standard PRE control products (pendimethalin, dithiopyr, prodiamine, benefin, etc.) for the standard winter annual weed complex of annual bluegrass, henbit and chickweed, fall PREs on non-overseeded bermuda fields typically must go out no later than the first week of September in the valley and ridge regions of VA, midSeptember in central VA and by October 1 towards Tidewater.

Early POST treatments of the winter annual weed complex are always desirable, as compared to combating the weeds next spring, and always keep in mind the possibility of using nonselective herbicides for POST control during winter dormancy periods on non-overseeded bermudagrass.

Spring dead spot (SDS) is problematic on most bermudagrass playing surfaces. While cold-tolerant varieties are often less prone to the disease, they are still susceptible, and damage may be severe. However, developing and continuing proper cultural management strategies can reduce severity over time. Core aerate to alleviate compaction, and improve drainage as site use permits. Judicious use of nitrogen during growing months will aid in recovery and can potentially reduce the likelihood of disease after multiple seasons. Nitrogen-source recommendations are based on the pathogen causing disease at each specific location. We are currently working on a geography-based model as a nitrogen-source decision tool.

Several DMI and QoI fungicides are

known to suppress SDS, although applications over multiple growing seasons are required for complete control. Tebuconazole is a cost-effective fungicide with above-average activity, but it is only available for use on golf courses. Several combination products with multiple active ingredients are available to all turf managers.

Final thoughts

Who knows what is in store for the winter of 2015–2016. Grass selection and management in the transition zone will always have its challenges.

However, if you follow these tips in preparing your bermudagrass for its dormancy period, your chances of having a great surface in the spring of 2016 will be greatly improved. c

Journal of the Virginia Turfgrass Council

| 15

Turf Basics

Organic Amendments for Turfgrass and Other Urban Landscapes

By Greg Evanylo, Ph.D., Professor and Extension Specialist, Dept. of Crop and Soil Environmental Sciences, Virginia Tech

O

rganic amendments marketed for use in turfgrass and other urban landscapes are typically recycled by-products derived from agricultural, municipal and industrial processes. Common by-products include animal manures and crop residues (agricultural); yard wastes, food residuals and biosolids (municipal); and papermill sludge and food-processing wastes (industrial).

These by-products must be treated by Processes to Further Reduce Pathogens

(PFRP) to generate a Class A product that can safely be applied to land accessible to the public. The PFRP treatment processes include heat treatment (pasteurization), drying and composting.

Class A products contain no detectable concentrations of pathogens and do not attract nuisance vectors, such as flies and vermin. In addition, products used in publicly accessible areas must also contain low levels of pollutants (such as heavy metals). When Class A products are also low in pollutants,

16 | Virginia Turfgrass Journal July/August 2015 www.vaturf.org

they are termed Exceptional Quality, or EQ, products. The processes used to treat these by-products ensure ease of handling and application, permitting their use in urban environments. Such products are increasingly being developed as soil amendments in lieu of disposal in landfills and incinerators.

By-products for turfgrass

Some of the most proven by-products for use in turfgrass are heat-dried and pelletized/granulated biosolids (treated

Biosolids heat-dried pellets.

Control

Auxinboosted biosolids

Biosolids

Biosolids-based amendments increase root growth under drought stress.

Finished compost.

Blowing compost as a highway roadside seeding medium.

human wastewater sludge). The most well-known product is Milorganite™ from the city of Milwaukee. These products are relatively high in nutrients, often containing more than 5% total nitrogen (N) and more than 2% phosphorus (P). They are considered slow-release forms of N, as the waterinsoluble N (WIN) usually comprises approximately 90% of the total N. In addition, only a portion (e.g., 30% to 50%, depending on the climate) of the total N is plant available during the

year of application because the organic N requires time to “mineralize,� or break down to a plant-available mineral form. Most of the P in these products is immediately plant-available. This can be problematic because applying these biosolids at rates to supply crop N needs often supplies excessive amounts of P, which can impair water quality if the nutrient runs off land into surface water.

An advantage of heat-dried biosolids products is that they usually contain

high concentrations of iron (Fe), which (1) can bind the P and make it less susceptible to transport in surface water and (2) is an important turfgrass micronutrient. These biosolids products contain all primary, secondary and micro essential plant elements, although they may not be present in the ideal balance required by plants. Potassium (K), especially, needs to be supplemented where EQ biosolids products are applied because K is found in low concentrations in these products.

Journal of the Virginia Turfgrass Council

| 17

Turf Basics Because these products are very dry (<10% moisture), they can be stored, handled and spread easily and with routine inorganic fertilizer equipment.

Animal manures can also be heat-dried and pelletized for urban landscape use, and their properties, advantages and disadvantages are similar to EQ biosolids. One advantage of animal manures over biosolids is that they contain higher concentrations of K. Heat-dried biosolids and manure products are considered the most slowly plant-available sources of N compared to moderately available sources such as sulfur-coated urea and Isobutylidene diurea and rapidly available ammonium sulfate and urea.

Because their organic N is slow to mineralize, N from heat-dried manure and biosolids is long-lived in the soil.

Other novel EQ biosolids products are being developed by combining biosolids treated by PFRP with moistureabsorbing materials (such as wood shavings or sawdust) to facilitate handling and spreading. One such product developed from the Alexandria Renew Enterprises (ARE), pasteurized biosolids has shown great promise as a soil amendment for sod production.

Other products combining biosolids, sawdust and mineral by-products (e.g., sand, rock dust) are being developed for use in urban environments.

2 in. compost PPI

The most prominent EQ biosolids product that makes use of such formulations is Tagro, a blend of Tacoma EQ biosolids, sand and sawdust. Tagro has performed so well and become so well accepted that it sells for $8 to $10 per cubic yard. A Tagro potting soil, composed of Tacoma biosolids and woody waste, sells for $30 per cubic yard.

Our research

Researchers at Virginia Tech have begun testing a Tagro-like product composed of ARE (VA) or Blue Plains (DC) Class A biosolids plus sawdust and mineral by-products (sand and quarry rock dust). The products performed as well as established organic soil amendments (Spotsylvania Countyâ&#x20AC;&#x2122;s Livingston composted biosolids and ARE dewated biosolids) for renovating a disturbed urban soil and producing quality turfgrass at the Virginia Tech Turfgrass Research Center. None of the organic products performed as well as inorganic fertilizer applied according to soil test recommendations. The better performance of inorganic fertilizer was likely due to (1) lower release or plant-available N from the organic sources than expected and (2) ability to split the inorganic fertilizer applications between September, April and June, whereas all of the organic amendments were applied at the

Std Fert+Straw Mat 1 in.

1 in.

Standard Fert 1 compost PPI /4 in. compost blanket compost blanket

The effects of treatments on early season turfgrass establishment on disturbed urban soils; PPI = pre-plant incorporated. Plots seeded March 24, 2009; photo taken April 17, 2009.

18 | Virginia Turfgrass Journal July/August 2015 www.vaturf.org

study establishment.

We continue to test the products for improving our understanding of the N release, which should permit us to make more accurate applicationrate recommendations. We are also testing the application timing of the organic by-products to learn whether we can improve their performance when applications are split throughout the year.

One benefit that we noticed with the organic amendments is that the quality of turfgrass grown under extreme drought did not decrease as much as that fertilized with the inorganic fertilizer. We believe that a combination of organic matter and organically derived biostimulants in organic by-products provide increased drought resistance.

Such drought resistance has been demonstrated by my colleagues, Dr. Erik Ervin and Xunzhong Zhang, and me in both greenhouse and field studies comparing biosolids to inorganic fertilizers. This new frontier in soil and plant biology should enable researchers to better understand the cause of such benefits of organic amendments.

Compost

Perhaps the most used organic amendment for renovating disturbed urban soils is compost. Composting is the highly managed, aerobic, thermophilic (i.e., high temperature), biological decomposition of any organic waste for production of a finished product termed â&#x20AC;&#x153;compost.â&#x20AC;? The feedstock for composting can be any organic waste and typically consists of the agricultural, municipal and industrial by-products listed above. Composts are valuable largely for their organic matter and typically contain lower amounts and availabilities of nutrients (especially N) than do the un-composted or heatdried manures and biosolids. Their organic matter is tremendously beneficial to disturbed soils whose nutrients and organic matter have commonly been removed with the topsoil. Revegetating such soils is difficult because the physical, chemical and biological properties of the natural soil have been degraded and often do not support

plant establishment or growth.

Compost is, therefore, not usually applied to supply a certain N, P or K application rate. Instead, compost is normally applied to such degraded soils at very high rates (e.g., 1 to 2 inches depth, or 135 to 270 cubic yards per acre). The common practice is to incorporate the compost into the top 4 to 6 inches of soil (20% to 30%) to replace the biologically active soil organic matter and re-create the soil chemical (increased cation exchange capacity and nutrient content, buffered pH) and physical (lower bulk density/ compaction, improved aggregation, increased porosity and water-holding capacity, better tilth) properties of the original natural soil.

Compost should be tested against industry standards to ensure that the product is good quality. The United State Composting Council (USCC) has supported researchers in the development of a testing protocol published

in the Test Methods for the Examination of Composting and Compost (TMECC) that many service laboratories have adopted. Composters who wish to demonstrate to consumers that their product is of high quality can become certified through the USCC Seal of Testing Assurance (STA) program.

Routine STA testing ensures that compost meets the many key parameters that differentiate quality (e.g., pH, electrical conductivity, bulk density, water-holding capacity, stability, maturity, nutrient content, organic matter or carbon content, pollutant content and content of inert materials).

Many researchers, including our program, have demonstrated the shortand long-term benefits of renovating degraded urban soils with compost for the improvement in soil (lower bulk density, increased water holding capacity, high nutrient and organic-matter contents) and vegetation (greater and higher quality growth and density).

Compost can be applied and incorporated into soil or as a turfgrass topdressing material at finer particle sizes (i.e., passing < Âź inch diameter screen). Both high-quality turfgrass and marginal lands, such as highway roadsides and acid sulfate roadcuts, have shown great benefits from compost.

Summary

Organic by-products are being used with great success for renovating degraded urban soils due to their high organic-matter contents, their nutrient contents and their potential biostimulant effects. Care must be taken to avoid applying excessive amounts of phosphorus to land when the products are applied to supply the nitrogen needs of the vegetation.

However, even under those situations, the improved soil tilth may reduce P runoff because of the amended soilâ&#x20AC;&#x2122;s increased infiltration and waterholding capacity. c

Journal of the Virginia Turfgrass Council

| 19

Applied Research

Measuring the Accuracy and Precision of Ball-Roll Devices â&#x20AC;&#x201D; Does Annual Bluegrass Influence Golf Ball Deceleration and Trajectory on Putting Greens?

By Sandeep S. Rana, Doctorate Student, and Shawn D. Askew, Ph.D., Associate Professor and Extension Turfgrass Weed Specialist, Virginia Tech

A

nnual bluegrass (Poa annua) infestation on putting greens is often speculated to impact ball-roll distance and trajectory.

Research at Virginia Tech showed that golf balls rolled almost a foot less when putting greens were infested with over 50% annual bluegrass compared to turf with less than 5% infestation.

The ability to remove annual bluegrass from putting surfaces may increase interest in surface-smoothness

evaluation. Several devices are now being marketed to golf superintendents for evaluating putting-surface smoothness and ball-roll distance and trajectory, but few research studies have tested these devices for effects other than ball-roll distance. In addition, most studies suggest that statistical differences in ball-roll distance are usually attributed only to treatments that create large differences in the putting-surface uniformity.

Figure 1. Golf ball-roll distance as influenced by ball-roll device and ball type.

20 | Virginia Turfgrass Journal July/August 2015 www.vaturf.org

Our hypothesis is that the potential effects of annual bluegrass on ball-roll distance and trajectory will be too small to measure with commercially available devices. Therefore, research was conducted to measure the accuracy and precision of several ball-roll devices and golf balls that can be used in future field experiments to determine subtle differences in ball-roll deceleration and trajectory due to annual bluegrass infestation on putting greens.

Our research

Laboratory studies were conducted in 2014 at the Glade Road Research Facility at Virginia Tech to select among 6 devices and 13 golf ball types for consistency of distance and trajectory. The ball-roll devices used in the experiment included three commercially available devices (USGA stimpmeter, PELZmeter and Greenstester) and three custom prototypes built at Virginia Tech (Putting Robot and two devices that used curvilinear inclined planes with a flexible ramp and carpet ramp designed to reduce golf ball oscillation; see Photo 1). Thirteen golf balls were selected based on use by both pro and entry-level golfers, covering almost all possible dimple patterns/designs and sizes.

The experiment was arranged as a split-plot design with 6 ball-roll-device main plots and 13 golf-ball-type subplots. Each of the 13 golf balls were rolled 20 times with each of the six ballroll devices and repeated three times for a total of 4,680 rolls. A synthetic, 11.5-stimp carpet manufactured for home-lawn putting greens was positioned on a leveled bench and brushed between each ball roll to control for legacy effects. Digital images of the resting position of each golf ball were taken with a camera installed facing down, perpendicular to the putting surface. Ball dispersion was measured via Sigma Scan Pro, and lateral precision and accuracy plus vertical distance were calculated. Data were analyzed using SAS 9.2, with sums of squares partitioned to reflect effects of ballroll device and ball type.

(Figure 2). The Greenstester’s lateral accuracy and precision were ± 60 and 32 mm, respectively (Figure 2). Thus, inherent variability from this device, although lower than other commercial devices, could be too high to detect subtle influences from green-surface factors, such as annual bluegrass.

The Putt Robot and flexible ramp prototype had the lowest variability in ball roll accuracy and precision (Figure 2). When averaged over ball roll devices, TaylorMade TPX golf ball was skewed ± 35 mm and lower than 10 out of the remaining 12 golf balls (data not shown). The differences in lateral accuracy of golf balls could be because of differences in the ball

construction (e.g., dimple pattern).

In conclusion, precision and accuracy of ball rolls do vary by ball-roll device and ball type. The Putt Robot and flexible ramp are the most consistent ball-roll devices, and TaylorMade TPX is among the most consistent golf balls, with the least deviation from the expected trajectory. Future efforts to measure the influence of annual bluegrass on golf ball deceleration and trajectory will utilize the Putt Robot and TaylorMade TPX golf ball under field conditions. c Thanks to our research sponsors, the Virginia Turfgrass Foundation and Virginia Agricultural Council.

Figure 2. Golf ball-roll lateral accuracy (left) and precision (right) as influenced by ball-roll device. Data are pooled over golf ball types. Means within the same response variable with same letter are not significantly different according to Fisher’s Protected LSD at the 5% level of significance.

PR = Putt Robot; FR = flexible ramp; CR = carpet ramp; GT = Greenstester; PM = PELZmeter; US = USGA stimpmeter.

Photo 1. (Left to right) Putt Robot built via modifying a Pendulum Perfect™ putt training aid, PELZmeter, Greenstester, USGA stimpmeter and VT prototypes with carpet and flexible ramp.

Research results

For ball-roll distance, there was a significant device-by-ball-type interaction.

The interaction was probably due to variability between ball types from the Putt Robot (Figures 1 and 2). When averaged over ball type, custom prototypes were more consistent than commercially available ball-roll devices (Figure 2). The PELZmeter and USGA stimpmeter had the greatest deviation in both lateral accuracy and precision

Journal of the Virginia Turfgrass Council

| 21

Research Report

PoaCure (Methiozolin) for Kentucky Bluegrass Fairways

By Sandeep S. Rana, Doctorate Student, and Shawn D. Askew, Ph.D., Associate Professor and Extension Turfgrass Weed Specialist, Virginia Tech

M

ethiozolin (PoaCure) is a new isoxazoline herbicide under development by Moghu Research Center (in Daejeon, South Korea) for use in turfgrass in the U.S. and other countries. Methiozolin is typically used at 26 fl. oz./A for selective postemergence control of annual bluegrass (Poa annua) on creeping bentgrass putting greens.

Previous research at Virginia Tech and Moghu Research Center, however, suggests that methiozolin at higher rates (52 fl. oz./A applied twice at monthly intervals) can also be used for annual bluegrass control on fairways.

Controlling annual bluegrass on Kentucky bluegrass fairways has always been challenging due to the physiological similarities in the genus Poa. Moreover, genetic diversity between Kentucky bluegrass cultivars can vary a great deal in response to the same herbicide, making selective annual bluegrass control with safety to Kentucky bluegrass challenging. This variability in response of different Kentucky bluegrass varieties to the same herbicide is attributed in part to variable ploidy levels and the unique apomictic breeding behavior of Kentucky bluegrass species. Since most previous work with methiozolin has been focused around the use on putting greens or green surrounds, more research is needed to elucidate methiozolin use on fairways.

Our research

Field trials were conducted from fall 2011 through spring 2012 and from fall 2013 through spring 2014 at the Virginia Tech Turfgrass Research Center (TRC) in Blacksburg. Permission was granted to use a five-year-old Kentucky bluegrass National Turfgrass Evaluation Program (NTEP) trial site for this study. The NTEP site had a total of 110 Kentucky bluegrass varieties belonging to different genetic groupings. These varieties reflect a broad range of diversity within Kentucky bluegrass varieties and within the major Kentucky bluegrass varietal classification types.

Each of the 110 Kentucky bluegrass cultivar plots was subdivided into 4 subplots, which were treated twice at a 6-week interval with methiozolin at 0 (NTC), 104 (2X), 208 (4X) and 312 (6X) fl. oz./A, respectively. Methiozolin rates used in the study are two-, fourand six-times higher than needed to control annual bluegrass in Kentucky bluegrass fairways. The higher methiozolin rates were used to mimic accidental overspray in the field and to achieve maximum varietal differences, which may not be apparent at the recommended 1X rate.

The applications for first-year treatments were applied on October 14, 2011, with sequential applications at 6 weeks after initial treatment (WAIT).

22 | Virginia Turfgrass Journal July/August 2015 www.vaturf.org

The second-year applications were made on November 17, 2013, with sequential treatments applied at the same intervals mentioned above.

Data were collected three times each in fall and spring following methiozolin applications. Data assessed included Kentucky bluegrass, annual bluegrass and broadleaf weed cover, as well as Kentucky bluegrass injury and quality.

Research results

When averaged over cultivars, methiozolin rates less than 6X did not injure Kentucky bluegrass more than commercially unacceptable levels (>30%) at 26 WAIT (Figure 1). At 6 WAIT, injury to Kentucky bluegrass from methiozolin was mainly in the form of stunting. However, at 26 WAIT, injury to Kentucky bluegrass was manifested as inability to grow into the voids created by dead annual bluegrass following methiozolin applications (Photo 1).

At 6 WAIT, methiozolin reduced turf quality at all rates (Figure 1). Reduction in turf quality was primarily due to annual bluegrass control, as annual bluegrass comprised approximately 40% of the turf area (Figure 2). At 26 WAIT, methiozolin at 2X increased Kentucky bluegrass quality higher than methiozolin at 4X, 6X and the untreated check (Figure 1). The lower Kentucky

bluegrass quality in the untreated check was because of high weed pressure. In the sub-plots treated with methiozolin at 4X and 6X, Kentucky bluegrass quality was lower because of empty voids following higher levels of weed control and the inability of Kentucky bluegrass to fill those voids left by dead annual bluegrass.

Methiozolin reduced cover of all weeds except parsley piert, 26 WAIT (Figure 2). The genetic group of Kentucky bluegrass cultivars does not appear to be a major factor governing Kentucky bluegrass response to methiozolin, but the assessment was confounded by lack of information regarding genetic parentage of various cultivars (data not shown).

Summary

Figure 1. Methiozolin rate’s main effect for Kentucky bluegrass injury (left) and quality (right). Means within a given response variable and rating date with the same letter are not significantly different according to Fisher’s Protected LSD at 5% level of significance.

Figure 2. Weed cover at 26 WAIT as influenced by methiozolin rate. Means within a given response variable with the same letter are not significantly different according to Fisher’s Protected LSD at 5% level of significance

In conclusion, methiozolin controls annual bluegrass and several other broadleaf weeds with commercially acceptable Kentucky bluegrass response on all varieties at two times (and on most varieties at four and six times) the rate needed for weed control.

Current and future efforts are aimed at developing methiozolin programs to control both annual and roughstalk bluegrass in Kentucky bluegrass and creeping bentgrass maintained at typical golf fairway heights. c Research Sponsor: Moghu Research Center, Daejeon, South Korea

Photo 1. Response of Kentucky bluegrass (cultivar ‘Bewitched’) to methiozolin rates at 6 WAIT (left) and 26 WAIT (right).

Journal of the Virginia Turfgrass Council

| 23

Research Summary

Confirming Glyphosate Resistance in an Annual Bluegrass Population Collected from Sports Turf

By Sandeep S. Rana, Doctorate Student; Shawn D. Askew, Ph.D., Associate Professor and Extension Turfgrass Weed Specialist; and John R. Brewer, M.S. Student, Turfgrass Weed Science, Virginia Tech

G

lyphosate is the cheapest and most commonly used herbicide for annual bluegrass (Poa annua L.) control in dormant bermudagrass turf. In 2013, a field manager at the Frank Liske Park in Concord, NC, reported an annual bluegrass population not controlled by glyphosate after six years of continuous applications.

Our research

Figure 1. Glyphosate rate needed to reduce annual bluegrass height at 7 WAT and biomass at 3 and 7 WAT by 50%. Uppercase letters within the response variable separate the means according to the Fisherâ&#x20AC;&#x2122;s Protected LSD at the 5% level of significance.

Plugs of suspected glyphosate-resistant annual bluegrass plants were collected from the site and screened for glyphosate resistance. The annual bluegrass population was found resistant to glyphosate (Roundup Pro Concentrate) at 13 fl. oz./A (0.42 kg ai/ha), the labeled rate for annual bluegrass control in dormant bermudagrass turf. The annual bluegrass population with glyphosate resistance selfpollinated in a greenhouse at the Glade Road Research Facility in Blacksburg to produce seeds.

Two greenhouse studies were conducted with an objective to compare locally collected glyphosate-susceptible annual bluegrass to the suspected resistant population for response to glyphosate. Additional greenhouse studies were conducted to determine if resistance to glyphosate in the suspected glyphosate-resistant annual bluegrass population confers resistance to other herbicides. Data were collected for annual bluegrass visual injury and height reduction at weekly intervals and for reduction in annual bluegrass biomass at three and seven weeks after treatment (WAT).

Replicate data were converted to percentage reductions compared to untreated plants and regressed against glyphosate rate using the hyperbolic function via SAS 9.2.

Estimated GR50 values were then calculated and subjected to analysis of variance to test for trial and biotype effects and interactions. Significant effects were separated using Fisherâ&#x20AC;&#x2122;s Protected LSD test at the 5% level of significance.

Research results

Photo 1. Response of suspected glyphosate-resistant and -susceptible annual bluegrass biotypes to 1, 2 and 4 times the labeled rate of glyphosate (13 fl. oz./A) for annual bluegrass control in dormant bermudagrass turf. The four pots on the left (RRs) represent the suspected resistant population, and the four pots on the right (Ss) represent susceptible annual bluegrass population.

The suspected resistant population of annual bluegrass was found to be resistant based on significantly different GR50 values from height and biomass data at 3 and 7 WAT. Resistance factors ranged between 2 to 18, depending on measured response variable.

This study confirms the first report of glyphosate-resistant annual bluegrass developed on athletic field turf. Research is currently underway to determine the mechanism of resistance in this annual bluegrass population. c

24 | Virginia Turfgrass Journal July/August 2015 www.vaturf.org

Investigating Creeping Bentgrass Response to Methiozolin, Ethephon and Core Cultivation

M

ethiozolin (PoaCure) is a new herbicide developed by Moghu Research Center in Daejeon, Korea, for the safe and selective removal of annual bluegrass (Poa annua) from turfgrass.

Ethephon (Proxy) is a plant growth regulator used to temporarily suppress annual bluegrass seedheads.

Previous research conducted on two Virginia golf courses indicated that methiozolin efficacy for annual bluegrass control and creeping bentgrass response may be impacted by ethephon.

We initiated four studies in 2012, 2013 and 2014 to determine whether or not the addition of ethephon to methiozolin programs would influence annual bluegrass control and creeping bentgrass safety. Two sites received core cultivation within two days of the second chemical treatment, and the other two sites were not core cultivated during the study.

The first trial was initiated on March 13, 2012, at Blacksburg Country Club on a mixed variety creeping bentgrass putting green (henceforth referred to as Core Cultivation #1 or CC1). The second trial was initiated on April 12, 2013, at the Virginia Tech Golf Course in Blacksburg on a ‘C-19 Congressional’ creeping bentgrass putting green (henceforth referred to as No Cultivation #1 or NC1). The third and fourth trials were initiated on April 10, 2014, on a mixed ‘C-19 Congressional’/ ‘C-1 Arlington’ at the Virginia Tech Golf Course (NC2) and on a ‘Penneagle’ putting green at the Virginia Tech Turfgrass Research Center (CC2) in Blacksburg.

Sequential applications were made four weeks after initial applications at all sites. Methiozolin at 26, 52 and 104 oz./ acre was applied alone or with ethephon at 218 oz./acre.

Initial annual bluegrass cover on the putting greens ranged from 48% to74%. At 6 WAIT at sites that received core cultivation, methiozolin controlled annual bluegrass 37%, 89% and 95% at 26, 52 and 104 oz./acre, respectively.

At sites that did not receive core cultivation, methiozolin controlled annual bluegrass 8%, 39% and 90% at 26, 52 and 104 oz./acre, respectively.

Ethephon did not influence annual bluegrass control at any site. Ethephon did, however, influence creeping bentgrass response. At sites that did not receive core cultivation, creeping bentgrass was not injured by any treatment. At sites that were core cultivated in conjunction with the second treatment, methiozolin alone did

By Kate Venner, Graduate Research Assistant, and Shawn D. Askew, Ph.D., Associate Professor and Extension Turfgrass Weed Specialist, Virginia Tech

Injury observed at four weeks after the second application of PoaCure when aeration occurred in conjunction with that application. No injury was observed when the site was not aerated.

not injure creeping bentgrass greater than 15%, while methiozolin at 52 and 104 oz./acre plus ethephon injured creeping bentgrass approximately 30% and 80%, respectively.

Injury occurred at CC1 and CC2 when the sequential application was applied within a few days of an aeration event.

This phenomenon was not observed at NC1 and NC2, as aeration did not occur during the course of the study.

These data suggest that, depending on site conditions and cultural practices, methiozolin and ethephon should not be applied together to avoid potential, undesirable turfgrass injury, and core cultivation should be delayed relative to methiozolin application timing.

Further research is needed to determine why methiozolin and ethephon interact unfavorably when core cultivation is performed close to application. c Research Cooperator: Suk-Jin Koo, Ph.D., Moghu Research Center, Daejeon, South Korea Research Sponsor: Moghu Research Center, Daejeon, South Korea Journal of the Virginia Turfgrass Council

| 25

Index of Advertisers Agronomic Lawn Management.................... 26 www.fertilizewithalm.com Alliance Material Handling, Inc..................... 5 www.alliancemat.com Buy Sod................................Inside Back Cover www.buysod.com Chesapeake Valley.......................................... 3 www.turfandnativeseed.com Collins Wharf Sod Farm............................... 15 www.cwsod.com Colonial Farm Credit.................................... 26 www.colonialfarmcredit.com Lebanon Turf................................. Back Cover www.countryclubmd.com Luck Stone Corporation............................... 15 www.luckstone.com Modern Turf, Inc............................................ 5 www.modernturf.com Progressive Turf Equipment, Inc.................. 3 www.progressiveturfequip.com Revels Tractor Co., Inc................................ 19 www.revelstractor.com Smith Seed Services...................................... 26 www.smithseed.com Southern States Cooperative........................Inside Front Cover www.southernstates.com The Turfgrass Group..................................... 7 www.theturfgrassgroup.com

Turfgrass Calendar August 25–26

December 7–10

Virginia Tech Blacksburg, VA

Belmont Recreation Center Henrico, VA

VT / Blacksburg Turfgrass Field Days

Virginia Tech’s Turfgrass Short Course

September 14

December 11

Wintergreen Resort — Devils Knob Course Wintergreen, VA

Belmont Recreation Center Henrico, VA

Bob Ruff Jr. Memorial Research Golf Tournament

Virginia Certified Turfgrass Professional Exam

September 15–17

January 25–28, 2016

(Nat. Rec. and Park Assn.)

Las Vegas, NV

Louisville, KY

(a joint conference between the Maryland Turfgrass Council and Virginia Turfgrass Council) Fredericksburg Expo & Conference Center Fredericksburg, VA

October 22–24

January 6–8, 2016

NRPA Congress and Expo

October 21–23

PLANET Green Industry Conference

GIE+Expo — Green Industry Equipment Expo and School of Grounds Management

Kentucky Expo Center Louisville, KY

Mid-Atlantic Turfgrass Expo

Mid-Atlantic Nursery Trade Show (MANTS)

Baltimore, MD

January 19–22, 2016

November 6–9

STMA Conference and Exhibition

(American Society of Landscape Architects) McCormick Place Chicago, IL

February 6–11, 2016

ASLA — Annual Meeting & Expo

Digital Marketplace Scan the QR code: Download your favorite QR reader to your phone and scan the code to learn more about these companies.

San Diego, CA

Golf Industry Show

San Diego Convention Ctr. San Diego, CA