Virginia Turfgrass Journal - November / December 2016

Journal of the Virginia Turfgrass Council

November/December 2016

A New Key to Consistent Poa annua Seedhead Suppression, and Not a Moment Too Soon

Japanese Stiltgrass — the Crabgrass of Shade Plus, Preview of the 2017 Mid-Atlantic Turfgrass Expo (M-A-T-E) January 30 – February 2

Journal of the Virginia Turfgrass Council | November/December 2016

16 10 Upcoming Event Preview of the 2017 Mid-Atlantic Turfgrass Expo (M-A-T-E)…

January 30 – February 2

14 Upcoming Event 2017 Come to the Bay Protect: Promote: Prosper February 28 – March 1

16 Cover Story

A New Key to Consistent Poa annua Seedhead Suppression, and Not a Moment Too Soon

20 DEPARTMENTS 6 Presidentʼs Message

from Rick Owens, CGCS

8 Directorʼs Corner

from Tom Tracy, Ph.D.

9 News from Virginia Tech 9 Virginia Tech Turf Team 24 Index of Advertisers 26 Turfgrass Calendar

20 Applied Research Japanese Stiltgrass — the Crabgrass of Shade 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 ©2016 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) 790-3718, 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.)

4 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org

President’s Message

Two

Important Events Coming Up Soon!

The

educational programs for the Mid-Atlantic Turfgrass Expo and the Come to the Bay event are displayed in this issue.

Be sure to check them out. A great lineup of speakers is on deck, with

some of the best education to be found on the East Coast. Many thanks to our tradeshow exhibitors for their support and participation.

Last year, which was the first year of our combined Virginia/Maryland show (or M-A-T-E), was heavily

Rick Owens, CGCS 2016–2017 President

impacted by a severe snowstorm.

While bad everywhere, this snowstorm was much worse in Maryland, which had the effect of reducing attendance from the Maryland folks quite a bit.

Let’s reach out to our Maryland peers and make sure they are aware of this year’s great event. The profits from this tradeshow are divided between the turfgrass research teams at Virginia Tech and the University of Maryland, so come on down all you, Marylanders.

The Mid-Atlantic Turfgrass Expo belongs to both Virginia and Maryland turf professionals. Fredericksburg is an easy drive from the D.C. metro area.

Turfgrass professionals from southern Maryland can take the 301 bridge south over the Potomac and avoid the D.C. traffic altogether. This is the premier event in the Mid-Atlantic area, so don’t miss it.

Everyone is also welcome at Come to the Bay. This event has no tradeshow, and the education has a slightly different focus, with a broader look at the other elements of the landscape. Trees, shrubs and landscape beds are given a larger focus along with the normal turfgrass issues. However, almost all turf managers deal with trees and shrubs and numerous other green-industry issues. This makes Come to the Bay a valuable experience. The conference takes place in Virginia Beach and, true to its name, is in a beautiful spot right on the Bay.

Rick Owens, CGCS 2016–2017 VTC President 6 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org

Director’s Corner

Two

Irresistible Days for Turf Professionals

The

2017 MidAtlantic Turfgrass Expo will start in a couple of months, and it will mark the second year of this joint venture between Maryland and Virginia.

Not only is M-A-T-E a partnership between state universities and associations, but also it is very unique in what happens to its money. We send one hundred percent (yes, 100%) of the profits to Virginia Tech and the Uni-

8 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org

Tom Tracy, Ph.D. VTC Executive Director

versity of Maryland. Where does the money go once it reaches these institutions? Turfgrass research.

Last year, the first year of M-A-T-E, was kicked off with a major challenge: between two and three feet of snow blanketed most of Virginia and Maryland just days before the event’s kickoff. Many attendees were unable to leave their homes; others were seeking to salvage sports fields and golf courses; others were helping clear roads; and more than one speaker was stranded in a distant airport. But, in spite of the record blizzard (weather forecasters referred to it as “snow-zilla”), we donated nearly $20,000 for turfgrass research!

“Please structure the program so we can do everything in two days,” was a refrain commonly heard during and after last year’s conference. You spoke, and we listened. M-A-T-E still spans four days (Monday through Thursday), but persons seeking quality education, maximum tradeshow time and basic pesticide and fertilizer certification can accomplish it all on Tuesday and Wednesday. Throw in two free lunches and the Tuesday evening Corn Hole Tournament, and you have an irresistible two days.

Although we hope to not have a repeat of the snow, the second year of M-A-T-E continues to provide cuttingedge education, opportunities to connect with your peers and an expanding tradeshow. Your participation directly affects turfgrass research!

News from Virginia Tech 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 Rick Owens, CGCS Laurel Hill Golf Club (703) 674-6934 Vice President Scott Woodward Woodward Turf Farms (540) 727-0020 Treasurer Michael Skelton Culpeper County (540) 727-3412 Past President Fredrick Biggers, CGCS Wintergreen Resort (434) 325-8252 VTC DIRECTORS Steve Glass Tony Montgomery Marc Petrus Jesse Pritchard, CSFM David Smith Rick Viancour, CGCS Jimmy Viars, CGM Craig Zeigler 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 Ph.D. EXECUTIVE DIRECTOR/ DIRECTOR OF PROGRAMS Tom Tracy, Ph.D. (757) 464-1004 VIRGINIA TURFGRASS FOUNDATION Betty Parker (757) 574-9061

Dr. Erik Ervin Named CSES Interim Department Head

In

mid-October, Dr. Alan L. Grant (Dean of Virginia Tech’s College of Agriculture and Life Sciences) announced that Dr. Erik Ervin will assume the role of interim head of the Crop and Soil Environmental Sciences (CSES) department, beginning November 1, 2016.

“I’m delighted that Erik will be providing leadership for the department,” said Dr. Grant. “I’m also very appreciative of Tom Thompson’s leadership and service while serving as the head, and to know that he’ll work closely with Erik to ensure a successful transition.”

Dr. Ervin himself estimated that the appointment will last for 10 to 12 months and end once the CSES department officially merges into the new School of Plant and Environmental Sciences (at which point, Virginia Tech will hire a director of the school).

“I will now be close to 100% Administration, as I will also keep serving as Assistant Dean for Academic Programs in CALS,” says Dr. Ervin. “I will keep teaching and advising our four-year turf students and maintain a small research program.”

Congratulations, Dr. Ervin!

Virginia Tech Turf Team Shawn D. Askew, Ph.D.

Mike Goatley Jr., Ph.D.

Virginia Tech 435 Old Glade Road Blacksburg, VA 24061 (540) 231-5807 saskew@vt.edu

Virginia Tech 420 Smyth Hall, CSES Dept.

Blacksburg, VA 24061 (540) 231-2951 goatley@vt.edu

Jeffrey F. Derr, Ph.D.

David McCall, Ph.D.

Virginia Tech Hampton Roads Agricultural Research Station 1444 Diamond Springs Rd. Virginia Beach, VA 23455 (757) 363-3912 jderr@vt.edu

Virginia Tech 435 Old Glade Road Blacksburg, VA 24061 (540) 231-9598 dsmccall@vt.edu

Erik H. Ervin, Ph.D.

Thomas P. Kuhar, Ph.D.

Virginia Tech 339 Smyth Hall, CSES Dept.

Blacksburg, VA 24061 (540) 231-5208 ervin@vt.edu

WITH SUPPORT FROM:

Virginia Tech Dept. of Entomology 216 Price Hall 170 Drillfield Drive Blacksburg, VA 24061 (540) 231-6129 tkuhar@vt.edu

Journal of the Virginia Turfgrass Council

|9

Upcoming Event

January 30 – February 2, 2017

MID-ATLANTIC TURFGRASS EXPO (M-A-T-E)

For up-to-the-minute updates and to register online, visit

www.turfconference.org Monday, January 30 1:00 p.m. – 5:00 p.m.

Turfgrass 101 Mike Goatley, Ph.D., Virginia Tech, and Tom Turner, Ph.D., University of Maryland 1:00 p.m. – 5:00 p.m.

Golf Session

Growing For Our Future Fredericksburg Conference & Expo Center Fredericksburg, VA

USGA Green Section Golf Turf Year in Review Darin Bevard, Director of Championship Agronomy, and Elliot Dowling, USGA Optimizing Annual Bluegrass Seedhead Suppression Shawn Askew, Ph.D., Virginia Tech Problematic Disease Issues of 2016 Steve McDonald, Turfgrass Disease Solutions Dollar Spot Suppression with Iron Sulfate David McCall, Ph.D., and Cam Shelton, Virginia Tech

Tuesday, January 31 8:00 a.m. – 9:30 a.m.

The Virginia Turfgrass Council and Maryland Turfgrass Council are delighted to invite you to the organizations’ second annual combined conference — the Mid-Atlantic Turfgrass Expo (M - A - T - E ) — slated for January 30 – February 2. Again this year, all profits from the event will be given to the turfgrass research projects at Virginia Tech and the University of Maryland!

Dress for both the educational sessions and the Expo is business casual.

10 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org

General Session Welcome MTC & VTC Annual Meetings Keynote Presentation — Bee Decline, Pesticides and Politics: Challenges and Opportunities for the Green Industry Dan Potter, Ph.D., University of Kentucky 8:00 a.m. – 4:00 p.m.

Mechanic’s Seminar Day One of Two (see page 12)

Tuesday, January 31 (continued)

Wednesday, February 1

9:45 a.m. –11:45 a.m.

9:45 a.m. – 12:45 p.m.

Turf/Horticulture Basics Taught in Spanish

Sod Production Session

9:45 a.m. – 12:45 p.m.

Golf Session Dollar Spot Development and Forecasting and New Control Methods John Inguagiato, Ph.D., University of Connecticut Barriers to Biological Control of Diseases of Cool-Season Turfgrasses Joe Roberts, Ph.D., University of Maryland Dealing with Extremes and Alternative Management Programs Jon Lobenstine, Montgomery County (MD) Golf Preventing Skin Disease Problems Molly Roberts, PA-C Dermatology 9:45 a.m. – 12:45 p.m.

Lawn Care Session Top 10 Nasty Insect Pests of Trees and Shrubs and How to Deal with Them Dan Potter, Ph.D., University of Kentucky Controlling Crabgrass, Goosegrass and Roughstalk Bluegrass in Turfgrass Jeff Derr, Ph.D., Virginia Tech Plant, Soil and Environmental Benefits of Compost Applications for Lawns Mark Carroll, Ph.D., University of Maryland The Latest on Weed Control in Ornamentals Kenneth Ingram, MS, University of Maryland

Maximizing Herbicide Efficiency and Efficacy in Difficult Years Steve McDonald, Turfgrass Disease Solutions Controlling Turf Insect Pests: It’s Getting Easier to Be Green Dan Potter, Ph.D., University of Kentucky Nutrient-Management Impacts on Early-Season Diseases of Cool- and Warm-Season Grasses in Sod Production Joe Roberts, Ph.D. University of Maryland 9:45 a.m. – 12:45 p.m.

Sports Turf Session A History of Technological Advances in Sports Turf Management Kevin Mathias, Ph.D., University of Maryland

7:00 a.m. – 8:00 a.m.

Fellowship Breakfast 8:00 a.m. – 4:00 p.m.

Mechanic’s Seminar Day Two of Two (see page 12) 8:00 a.m. – 4:30 p.m.

Pesticide Recertification (3A, 3B, 60 ONLY) 8:00 a.m. – 10:00 Part One of Two 10:00 a.m. – 1:00 p.m.

Trade Show and Lunch 1:30 p.m. – 4:30 p.m.

Part Two of Two 8:00 a.m. – 10:00 a.m.

University of Maryland and Virginia Tech Research Updates University of Maryland and Virginia Tech faculty, staff and graduate students will give short research updates, summarizing their most current and pertinent research findings for the Mid-Atlantic turfgrass industry.

10:00 a.m. – 2:00 p.m.

Trends in Cultural Management Practices in Intensely Maintained Sports Turf John Turnour, Washington Nationals Baseball

Tradeshow and Lunch

Weed Control in Trafficked Systems Shawn Askew, Ph.D., Virginia Tech

Thursday, February 2

Summer Patch Issues & Control in Sports Turf John Inguagiato, Ph.D., University of Connecticut 12:45 p.m. – 2:00 p.m.

Lunch — Free with registration.

12:45 p.m. – 7:30 p.m.

TRADESHOW Please visit our exhibitors!

5:30 p.m. – 7:30 p.m.

CORN HOLE TOURNAMENT

Please visit our exhibitors!

2:00 p.m. – 5:00 p.m.

Virginia and Maryland Sod Growers Meetings

8:00 a.m. – 4:00 p.m.

Pesticide Recertification 8:00 a.m. – 12:00 p.m.

Fertilizer Recertification (VA and MD) 9:00 a.m. – 3:30 p.m.

Virginia Certified Fertilizer Applicator Training and Examination 8:00 a.m. – 4:00 p.m.

Initial Pesticide Review of Core and Offering of Pesticide Exams for Virginia (You must bring an approval letter from VDACS. We are seeking to add MD.)

Next to the tradeshow floor.

Journal of the Virginia Turfgrass Council

| 11

Upcoming Event continued

Don’t Miss the

During the

MID-ATLANTIC TURFGRASS EXPO January 31 – February 1, 2017 Tuesday, January 31

Wednesday, February 1

Registration Details

Morning Session

Morning Session

Only $70

Small Engines

Tier 4 Diesel Engines

for VTC and MTC Members

Lunch

Late Morning

$95

Included with Registration

Visit the M-A-T-E Tradeshow

for Non-Members (Fees increase after January 10.)

Afternoon

Lunch

Register online at

Visit the M-A-T-E Tradeshow

Included with Registration

www.turfconference.org

Afternoon Session Landscape Equipment Maintenance

12 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org

or use the registration form on the next page.

Upcoming Event continued

Registration Form

MID-ATLANTIC TURFGRASS EXPO (M-A-T-E) January 30 – February 2, 2017 • Fredericksburg, VA • Fredericksburg Conference & Expo Center Program and lodging information: www.turfconference.org Full Name: ___________________________________________ (First name for badge): _______________________________ Company/Organization: ____________________________________________________________________________________ Preferred Mailing Address: __________________________________________________________________________________ City: _________________________________________________ State: _____________ Zip/Postal Code: __________________ Telephone:(______) ___________________________________ Fax:(______) ________________________________________ Email: ____________________________________________________________________________________________________ CONFERENCE FEES (POSTMARKED BY JANUARY 10; Prices increase after that date.)

1. Registration Fees MTC OR VTC MEMBER MONDAY, TUESDAY, WEDNESDAY Member Rate Non-Member Rate One Day $90 $125 Two Days $170 $205 Three Days $250 $285 Mechanic’s Seminar ONLY $70 $95 FREE

THURSDAY

$60

WHEN ARE YOU ATTENDING? Circle the day(s).

Monday; Tuesday; Wednesday; Mechanics Seminar; Thursday COST:

$ _________________________

2. Attend Trade Show ONLY ($20 per Day, includes Lunch and Tuesday Reception) WHEN ARE YOU ATTENDING? Circle the day(s): Tuesday or Wednesday

$ _________________________

3. JOIN OR RENEW YOUR MEMBERSHIP

$ _________________________

VTC Regular Membership (January 1 – December 31) $85 MTC Regular Membership (February 1 – January 31) $50 Further membership options at http://turfconference.org/registration.html Total Enclosed

$ _________________________

Cancellations/Changes and Refunds:

Fees for missed meals, late arrivals and early departures will not be refunded. Fees will be refunded, less a $20.00 processing fee, if cancellation or change resulting in a refund is received in writing no later than January 10, 2017. After that date, fees are non-refundable. All refunds will be processed after the conference. Substitutions are allowed at no charge.

PAYMENT METHOD: Check to: Mid-Atlantic Turfgrass Expo (or MATE). Registration confirmation/receipt will be mailed.

Please check appropriate box: Check AMEX VISA MasterCard Card #: ______________________________________________ Print Cardholder Name:_______________________________ Card Security Code Number: ___________________________ Expiration Date: _____________________________________ Please mail, fax, or scan and email completed registration form with payment to: M-A-T-E P.O. Box 5989 Virginia Beach, VA 23471

Phone: (757) 464-1004 FAX: (757) 282-2693 Email: vaturf@verizon.net Journal of the Virginia Turfgrass Council

| 13

Upcoming Event

February 28 – March 1

2017PROTECT: Come to the Bay PROMOTE: PROSPER Tuesday, February 28 8:00 a.m. – 4:00 p.m.

Pesticide Recertification Register at 7:30 a.m.

8:00 a.m. – 12:00 p.m.

Initial Pesticide Training 9:00 a.m. – 4:00 p.m.

Green Industry Team Leadership Day One of Two 11:30 a.m. – 5:00 p.m.

Certified Fertilizer Applicator Training and Exam 1:00 p.m. – 5:00 p.m.

Pesticide Exams

10:30 a.m. to 4:00 p.m.

Irrigation Workshop by SiteOne Landscape Supply

Tuesday Only — no charge for members

MORNING BREAKOUT SESSIONS

Wednesday Only — $95

Turf/Horticulture Basics Taught in Spanish Lawn/Landscape Annual Grass Control for Turfgrass & Ornamental Beds Jeff Derr, Ph.D., Virginia Tech Tree/Turfgrass Interactions Mike Goatley, Ph.D., Virginia Tech

Arborist Stem-Girdling Roots Joel Koci, Aborcare Professional Tree Service

4:30 p.m. – 6:30 p.m.

Social Mixer (onsite)

Management of the Urban Forest Chad Peevy, Old Dominion University

8:00 a.m. – 10:00 a.m.

General Session Preserving the Elizabeth River through Proper Green-Industry Practices Barbara Gavin, Elizabeth River Project Restoring the Chesapeake Bay — Progress and Opportunities Ann Jennings, Chesapeake Bay Commission Industry Challenges with a Focus on the Transition Zone Mike Goatley, Ph.D., Virginia Tech We’re All in This Together Craig Zeigler, Agronomic Lawn Mgmt.

8:00 a.m. – 4:00 p.m.

Green Industry Team Leadership: Day Two 8:00 a.m. – 2:00 p.m.

Career Day for High School Students

VTC MEMBER RATES

10:30 a.m. – 12:00 p.m.

Must have prior permission from VDACS to take exam.

Wednesday, March 1

Registration Details

Tuesday and Wednesday — $95 Tuesday, Wednesday and GITL — $115

NON-MEMBER RATES Tuesday Only — $75 Wednesday Only — $135 Tuesday and Wednesday — $175 Tuesday, Wednesday and GITL — $195

OPTIONAL* Unless you object, $10 of your registration fee will be sent to one of the following: Turfgrass Research at HR-AREC

Lunch and Networking

Bonnie Appleton Memorial Scholarship (VA Tech)

Lunch on your own.

No thanks. I prefer not to have money sent.

12:00 p.m. – 1:30 p.m.

1:30 p.m. – 4:00 p.m.

AFTERNOON BREAKOUT SESSIONS Lawn/Landscape Working with First Responders Stephen Connally, City of Norfolk Fire Dept.

Equipment Maintenance and Safety Jeffrey Kline, Virginia Beach City Public Schools Meadow Management Michael Moore, City of Virginia Beach

* This decision is optional, is part of the registration fee and, therefore does not qualify as a taxexempt donation. If no boxes are checked, $5 will be sent to each of the two funds.

REGISTRATION Register online at www.cometothebay.org, by using PayPal or by downloading a form to return to us.

Hotel Information Attendee Special Rates ...............................$89!

Arborist Working with First Responders Stephen Connally, City of Norfolk Fire Dept.

Community Forestry Michael Nentwich, City of Norfolk Physiology of Woody Plants Joel Koci, Aborcare Professional Tree Service

14 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org

The Virginia Beach Resort Hotel & Conference Center is located at the mouth of the Chesapeake Bay — 2800 Shore Drive Virginia Beach, Virginia 23451 Reserve your room by contacting the hotel directly at 800-468-2722 (mention you are with Come to the Bay).

Journal of the Virginia Turfgrass Council

| 14

Cover Story

A New Key to

Consistent Poa annua Seedhead Suppression, and Not a Moment Too Soon

By Shawn Askew, Ph.D., Associate Professor, Turfgrass Weed Science, Virginia Tech

A

nnual bluegrass (Poa annua) seedhead suppression has long been among the more “unpredictable” turf-management objectives that superintendents face. One challenge is that annual bluegrass is one of the most adaptable plant species on the planet, leading to a broad range of genetic diversity that spans geography and management intensity. In addition, several interacting factors contribute to stimulate floral primordia.

Product evaluations Embark T&O Embark T&O (mefluidide) is an established seedhead suppressor, generally considered to suppress seedheads better with increasing rates. Embark at effective rates (1 fl. oz./1,000 ft2), however, injures both annual bluegrass and creeping bentgrass (Agrostis stolonifera). Adding chelated iron can decrease turf discoloration by Embark,

but the tank mixture tends to promote Embark precipitation, lowering product efficacy when the two products are applied together.

A recent decision by the 3M Company to reduce waste in the manufacturing of a common spray adhesive has nearly eliminated the availability of mefluidide, a waste product in the manufacturing process and the active ingredient in Embark. Efforts to manufacture mefluidide directly are said to be cost prohibitive. Thus, this longstanding seedhead suppressor’s availability has been limited in recent years and may be phased out completely.

Proxy Proxy (ethephon) was first marketed for seedhead suppression in turf about 15 years ago and generally offers improved turf safety over Embark. As with most products, the safety of Proxy on creeping bentgrass and annual bluegrass turf is not absolute. In warmer

16 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org

climates or warmer times of the year, Proxy can cause “crown rising” of creeping bentgrass that leads to scalping-associated discoloration on greens.

In northern climates, applying Proxy during late spring, especially on thatchy greens, will likely cause the crown rising problem to appear in early summer. In the deep South, Proxy has been associated with severe declines in turf quality and root density of creeping bentgrass. The reason for root loss in hot climates is unknown, but recent research at Virginia Tech suggests that Proxy may accentuate root senescence following turf stress.

In a trial conducted on four Virginia putting greens, Proxy at 5 fl. oz./ 1,000 ft2, when mixed with Poacure (methiozolin), interacted with core aeration stress to cause creeping bentgrass stand loss. Treatments were applied at 50 growing degree days at a 50°F base temperature (GDD50) (March 2012, April 2013 and April 2014) and

repeated three weeks later. Poacure alone did not injure creeping bentgrass at any rate, but when mixed with Proxy on greens that were aerated a few days after treatment, up to 90% creeping bentgrass stand loss was observed at the 2.4 fl. oz./1,000 ft2 (4 X) Poacure rate. When core aeration was separated from chemical treatments by at least two weeks, creeping bentgrass was not injured by any treatment.

The theory has not yet been confirmed, but it seems that aeration stress interacted with Proxy to cause root loss that could not be replenished by creeping bentgrass crowns in the presence of Poacure. Poacure can inhibit root growth when root tips are exposed to the product, a situation that normally would not occur on a green unless severe stress caused root loss, requiring new root growth from turfgrass crowns. If Proxy is causing root loss following aeration stress on greens, we normally would not notice

symptoms on a well-irrigated green since creeping bentgrass can replenish roots quickly in cool weather. Therefore, don’t mix Poacure with Proxy, especially if mechanical or environmental stress is expected on greens.

Proxy also tends to cause transient yellow to orange discoloration of annual bluegrass, especially when spring weather presents intermittent frost events. Primo Maxx (trinexapac ethyl) is typically mixed with Proxy to improve both turf density and color. When spring applied in the transition zone and areas further north, this combination of Proxy and Primo Maxx is extremely safe on putting greens, but it tends to deliver highly variable annual bluegrass seedhead suppression between locations and years.

In an analysis of 195 observations from published reports, Proxy suppressed seedheads 56% on average with a standard deviation of 28% across 11 northeastern or northcentral U.S. trials. In 21 replicated research trials conducted in Virginia in the past 15 years, seedhead suppression provided

by Proxy applied in the spring has also been similarly variable. These data suggest that about 70% of Proxy applications can be expected to reduce seedhead cover between 28% and 84% compared to nontreated turf.

To reduce this variable seedhead suppression by Proxy, we have tried almost everything in the book at Virginia Tech. We quickly recognized, like others, the value of proper application timing and have successfully employed growing degree day application thresholds based on both 32°F and 50°F base temperatures. In the Mid-Atlantic region, applying Proxy at 50 GDD50 or 400 GDD32 (base 32°F) typically maximizes efficacy. We have even utilized black sand to “heat up” the green. We were able to rapidly initiate annual bluegrass seedhead emergence using black sand, and this allowed our Proxy applications to be timed precisely relative to seedhead emergence. The result was still poor seedhead suppression in the first four weeks of the season. After much experience, it became apparent that all of our application timing research only

served to optimize what was inherently variable seedhead suppression

by Proxy.

So what is the source of the variability? Poa annua’s genetic diversity, as many have proposed? No. Despite similar trial conditions and applications timings, Proxy would work great one year at a given location but not the next. Although genetics probably plays an important role, it can’t explain all of the variability.

Poa flowering The term “flowering” is used loosely and involves photoperiodic induction, floral evocation and floral differentiation. The photoperiod-based induction process is fairly well studied, but the processes of evocation and differentiation are far less understood.

Chemical compounds, yet to be discovered and labeled as “florigenic stimuli” or “florigens,” are believed to travel through the plant using nutrient-conducting tissue to kick-start floral evocation at the growing point.

Hormones, similarly translocated, are believed to play a role in the floral differentiation stage. Since the production and translocation of chemical stimuli for floral initiation are influenced by environmental conditions, it stands to reason that a high percentage of annual bluegrass plants will “initiate seedhead formation” during warm periods in winter. Spring-applied Proxy will not prevent seedheads on these plants if floral differentiation has already begun.

About five years ago, I started evaluating “early” applications of Proxy in winter and fall to test a hypothesis that these winter-initiated floral primordia could be prevented. The results were astounding. In 51 side-by-side comparisons within 13 field trials at various Virginia golf courses, the normal spring program of Proxy at 5 fl. oz./1,000 ft2 + Primo Maxx at 0.125 fl. oz./1,000 ft2 suppressed seedheads 58%, with a standard deviation of 17%. When an early application was included with a normal spring program, seedhead suppression was improved to 95% with a standard deviation of 5% in these same trials.

Journal of the Virginia Turfgrass Council

| 17

Cover Story continued

Figure 1. Percentage of annual bluegrass displaying seedheads at peak bloom 6 weeks after 50 GDD50 averaged over putting green trials in Blacksburg and Harrisonburg, VA, in 2012. Proxy at 5 fl. oz./1,000 ft2 was applied at various winter timings and followed by the spring program of Proxy at 5 fl. oz./1,000 ft2 + Primo Maxx at 0.125 fl. oz./ 1,000 ft2 twice at a 3-week interval.

Figure 2. Influence of Proxy + Primo Maxx or Embark T&O spring programs (Spring) ± a February early application of Proxy or Embark (Winter) ± a 90 GDD50 treatment of Bayleton at 1 fl. oz./1000 ft2 (DMI) on creeping bentgrass and Poa annua injury and suppression of peak Poa annua seedhead production averaged over putting green trials in Blacksburg, VA (2011), and Harrisonburg, VA (2012).

Photo 1. Virginia Tech graduate student, Sandeep Rana, collecting spectral reflectance data on seedhead suppression studies. The plot to Sandeep’s left is a spring only program of Proxy + Primo Maxx that suppressed seedheads about 60%. Surrounding plots included fall or winter applications of Proxy in addition to the spring program, improving seedhead suppression to over 90%.

18 | VIRGINIA TURFGRASS JOURNAL

Data from nontreated turf shows that the duration of Poa annua seedhead production at Spotswood Country Club in Harrisonburg, VA, was about 80 days in 2012. We often see the spring Proxy + Primo Maxx program perform inconsistently during the first four weeks of the spring season, but seedhead suppression generally improves later in the season, after the second application has been made.

Applying Proxy at 5 fl. oz./1,000 ft2 at least one month prior to the normal spring GDD-based program of Proxy at 5 fl. oz./1,000 ft2 + Primo Maxx at 0.125 fl. oz./1,000 ft2 nearly eliminates seedhead production in most cases (Figures 1 and 2 with Photo 1).

Winter application timing did not strongly influence performance if Proxy was applied at least one month before the spring GDD-based treatments, which was late March in 2012 (Figure 1). Proxy was always safer to both annual bluegrass and creeping bentgrass compared to mefluidide (Figure 2).

A particular concern with fall or winter Proxy applications is the potential effect that additional Proxy applications may have on Poa annua winter survival in the extreme north.

In Virginia, our research can’t directly answer this question, but we can say that these Proxy programs have not reduced Poa annua cover and were considerably safer to Poa annua than Embark programs in every evaluation.

Recent research is proving that fall Proxy treatments applied between mid-November and mid-December work equal to or better than winter treatments to improve efficacy for seedhead suppression (Photo 1).

Fall applications are much easier to implement than winter applications due to seasonal weather patterns and lack of snow cover in most locations.

Proxy applications prior to November 15 are not advised in our area since seedhead suppression was reduced in research trials.

Our recommendations Our current recommendation for Mid-Atlantic states is to apply Proxy alone in late November or December

Cover Story continued

and follow with Proxy + Primo Maxx in spring using 400 GDD32 or 50 GDD50 as the initial spring trigger and repeating the mixture 3 to 4 weeks later. This program works great in areas where greens tend to enter winter dormancy soon after the fall treatment since these fall treatments can increase winter-associated leaf tip burn and decrease new leaf growth that would otherwise mask frost injury. Use of a pigment-containing product has improved winter turf quality in several of our trials and may be appropriate for southern or coastal locations where greens do not go completely dormant.

We have also evaluated these winter and fall applications with Helena’s ethephon product, Huskie, with the same response. Both Proxy and Huskie programs exhibit dramatically improved seedhead suppression when a fall or winter treatment was applied in advance of a normal spring twoapplication program.

In collaboration with Adam Van Dyke (owner of Professional Turfgrass Solutions, LLC) in the past two years, we have evaluated early applications of these two products in both fall and winter, with multiple trials conducted in Virginia and Utah. There has been no significant difference between fall and winter applications and only slight improvement in seedhead suppression when both fall and winter applications are applied prior to a normal twoapplication spring program. Thus far, we have not observed unacceptable injury to Poa annua or creeping bentgrass, even when both fall and winter applications were applied. We are currently evaluating plant health products to promote potential winter stress defense with fall ethephon treatments.

In seedhead suppression research at Virginia Tech in the past 5 years, adding early ethephon applications dramatically improved seedhead suppression over traditional spring programs alone in every comparison within 15 replicated putting green and fairway research trials across Virginia.

In the past two years, other university scientists have started evaluating these programs with reportedly similar results. Based on my correspondence

with superintendents in the eastern U.S. and social-media discussions, it appears that many superintendents have also adopted these programs with general success.

Future efforts at Virginia Tech will include various tank mixtures and approaches to economical seedhead suppression on fairways and incorpo-

ration of other growth regulators, such as Anuew (prohexadione calcium), Trimmit (paclobutrazol) and Cutless (flurprimidol) into these programs on both greens and fairways.

Editor’s note: This article was published in a recent issue of Golfdom magazine.

Journal of the Virginia Turfgrass Council

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Applied Research

e d a h S Tech f o (Microst inia s g r s i V a egium) — the Crabgr enter, sion C n e t x E h and esearc . Derr, Ph.D., Professor of Weed Science,Hampton Roads Ag. R

By Jeffrey F

J

apanese stiltgrass (Microstegium vimineum), a widespread weed in Virginia, has also been referred to as annual jewgrass, bamboograss, flexible sesagrass, Japanese grass, Mary’s grass and Nepalese browntop. I often call it Microstegium because of the confusion with the various common names. This plant is a shadetolerant C4 summer annual grass.

A native of Asia, it was first discovered in the U.S. in 1919 near Knoxville, Tennessee. It apparently it was used as packing material for porcelain from China, and this may have been how it was introduced into the U.S. From this initial infestation, it has spread rapidly and is now widely distributed throughout the eastern United States. Microstegium has moved into New England and the Midwest and has been reported as far west as Texas.

This weed occurs throughout Virginia.

Microstegium has a large, somewhat circular cotyledon, separating it from other annual grasses. Microstegium has a fibrous root system, with stems that are upright or reclining, and stems can root at the nodes. Plants can reach up to three feet tall. Microstegium pro-

duces tillers that can root into the ground, allowing the plant to spread laterally. Leaves are about four inches long and one-half inch wide and taper at both ends. Most leaves have a distinct white midvein; however, a key identifying feature of this grass is that the midvein does not divide the leaves into equal halves. The seedhead is composed of one to six terminal spike branches.

Unlike most C4 plants, Japanese stiltgrass is uniquely adapted to low light conditions. I refer to it as the crabgrass of shade since it grows in moderate to dense shade and spreads laterally by rooting at the nodes, allowing a single plant to cover a significant area. Microstegium is under stress in dry, full-sun environments, so expect to find it primarily in shady areas. Japanese stiltgrass occupies a range of shady, moist habitats including riverbanks, flood plains, damp fields, swamps, woodland thickets, roadside ditches, river bluffs and roadsides. The weed can invade landscape ornamental plantings, turfgrass and vegetable gardens.

Microstegium can out-compete native plant species in shaded areas

20 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org

and, thus, is a major invasive species.

Since Japanese stiltgrass is an important weed in Virginia, I have been conducting experiments on the biology and management of this weed.

When does Microstegium germinate?

An important question to answer for any annual weed is when does it start to germinate? This information is needed to determine timing of preemergence herbicide applications.

I conducted experiments in several locations in southeastern Virginia to determine the germination pattern for this weed. In Virginia Beach, this grass does not flower until the first or second week of October, late for a summer annual grass. So, I expected that it started to germinate later than other summer annual grassy weeds, but that was not the case.

Actually, Microstegium started to germinate about a week before smooth crabgrass in my trials. It can start germinating by the second or third week of March in southeastern Virginia, depending on temperature. This year I had Microstegium up to three inches

Applied Research continued

tall with two to four leaves on April 6 in my trial, showing how early this plant grows.

So, Microstegium is an early germinating but late-flowering summer annual. Applications for preemergence control, therefore, must be made earlier than ones for crabgrass control, ideally by the first week in March for southeastern Virginia.

Can Microstegium be controlled using preemergence herbicides?

I have evaluated a number of preemergence herbicides for Microstegium control. Balan (benefin), Barricade (prodiamine), Bensumec (bensulide), Dimension (dithiopyr), Pendulum (pendimethalin), Ronstar (oxadiazon), Specticle (indaziflam), Surflan (oryzalin), Team (benefin plus trifluralin) and Tupersan (siduron) applied preemergence all controlled Microstegium when evaluated a month after application. As with crabgrass control, some of these herbicides provided longer-term control than others.

Multiple applications may be needed for full season control, especially in wet springs. Also, check the label to determine what sites can be treated with a given herbicide.

One problem with preemergence herbicides is that any Microstegium plants that escape an application may grow to be quite large by the end of the season due to its ability to spread laterally. Hand-weeding or postemergence herbicides could be used to control escapes from a preemergence application.

What about postemergence control?

I have evaluated postemergence herbicides for control of Microstegium.

The postemergence grass herbicides Acclaim Extra (fenoxaprop), Envoy (clethodim), Fusilade II (fluazifop) and Segment (sethoxydim) all control Microstegium and can be applied to many broadleaf ornamental species as well as many non-grass monocots like liriope, hosta and daylily. In addition, Acclaim Extra can be used for

Japanese stiltgrass (Microstegium) is a widespread weed in Virginia.

Microstegium seedhead.

selective control in cool-season turfgrass. Pylex (topramezone) also will control emerged Microstegium with two applications and would be an alternative option in cool-season turfgrass. Specticle FLO if applied to small Microstegium plants will provide control, although this herbicide is more effective if applied preemergence.

The nonselective herbicides Finale (glufosinate) and Roundup ProMax (glyphosate) also control this weed.

Other researchers have shown that very low rates of glyphosate control Microstegium, so this nonselective herbicide could be made somewhat selective by lowering the application rate. The semi-selective compound Plateau (imazapic) can be used for Microstegium control in noncropland

22 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org

and other areas. I have controlled fairly large plants (one foot or more tall) of Microstegium with the postemergence grass herbicides, Finale, Roundup and Plateau, so there is a lot of flexibility in application timing.

Daconate (MSMA) injured Japanese stiltgrass, but treated plants were able to regrow. Dimension and Drive (quinclorac) applied postemergence did not control Microstegium in my trials.

Conclusion and suggestions for control Microstegium tolerates frequent mowing (for example, in turf areas).

In areas that are not regularly mowed, however, and where Microstegium has grown to several feet tall during the

Applied Research continued

summer, mowing is a way to stop seed production. Since Microstegium is an annual weed, stopping seed production is an important step in long-term eradication programs.

In our trial, cutting large plants down to two inches or less in early September resulted in excellent seedhead prevention since the plants did not have enough time to grow and flower before frost killed them. So, timing a mowing about a month before normal seedhead appearance in unmowed areas would help reduce the seed available for germination in future years.

The general feeling is that Microstegium seed is short-lived in soil, perhaps five years or less. Thus, if one can stop seed production for several years, the Microstegium population will be drastically reduced. Mowing may not be practical for certain noncrop sites infested with Japanese stiltgrass, but it would be an option where someone desired an alternative to herbicides.

Microstegium germinates slightly earlier than smooth crabgrass and other common summer annual grasses, yet it flowers later. Hand-weeding is an effective control option but is labor intensive for large areas. Also, additional plants may germinate after hand-weeding, requiring one to make repeat trips to the site. Microstegium tolerates mowing heights used for cool-season turfgrass, so mowing will not control existing plants. Since this

Microstegium treated with Barricade (on the left) and untreated (on the right).

plant must set seed in order to germinate in subsequent years, a late-season mowing where plants have been allowed to grow tall will suppress seed production.

Depending on the site, preemergence control of Microstegium is possible if treatments are applied earlier than you would use for crabgrass control. In turfgrass, an application of a long-residual preemergence herbicide like Barricade would be a good option.

Barricade is also an option in established landscape beds. For a broader weed-control spectrum, look at Snapshot or FreeHand as granular control options in ornamental beds, or make a sprayable application of products such as Gallery (isoxaben) plus Surflan (oryzalin). Selective control options are available for cool-season turfgrass,

broadleaf ornamentals and non-grass ornamentals through use of Acclaim Extra, which can also be used in rightsof-way. Esplanade (indaziflam), Endurance (prodiamine) and Pendulum AquaCap are three options for preemergence control in noncrop areas, while Plateau and Roundup ProMax are two of the options for postemergence control.

Check the herbicide label for specific information on use for all of these products. These chemicals all have generally low toxicity to animals since they primarily affect processes that occur only in plants. These chemicals are commonly used by companies in lawn care and landscape maintenance, and most of the chemicals listed are readily available to homeowners as well.

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24 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org

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Journal of the Virginia Turfgrass Council

| 25

Turfgrass Calendar December 5–8

February 4–9, 2017

Turfgrass Short Course

Golf Industry Show

Belmont Golf Course Henrico, VA

January 30 – February 2, 2017

January 24–27, 2017

Mid-Atlantic Turfgrass Expo

STMA Conference

Fredericksburg Expo & Conference Center Fredericksburg, VA

and Exhibition

Orlando, FL

DIGITAL Marketplace

Orange County Convention Center Orlando, FL

February 20–23 TPI International Education Conference & Field Day

(Turfgrass Producers Intl.)

Saddlebrook Resort Tampa, Florida

February 28 – March 1, 2017 Come to the Bay

Virginia Beach Resort Hotel Virginia Beach, VA

May 23–24, 2017 Come to the Valley

James Madison University Harrisonburg, VA

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

26 | VIRGINIA TURFGRASS JOURNAL November/December 2016 www.vaturf.org