Tennessee Turfgrass - August / September 2009 by leadingedgepubs

The Official Publication of the Tennessee Turfgrass Association, the Tennessee Valley Sports Turf Managers Association and the Tennessee Golf Course Superintendents Association

The Official Publication of the Tennessee Turfgrass Association, Tennessee Valley Sports Turf Managers Association and the Tennessee Golf Course Superintendents Association

TA B L E O F C O N T E N T S AUGUST/SEPTEMBER 2009

Cover Story

Turf Talk

Turf Tips

F E AT U R E D A RT I C L E S

Managing Naturalized Areas on Golf Courses... Maintenance Tips to Keep Weeds at Bay and Balls in Play

Turf Talk — Important News: EPA Imposes Restrictions on MSMA Use in Turf

Turf Tips — The Benefits of Using Plant Growth Regulators

D E PA RT M E N T S

From the TTA President, Bob Hogan

From the TVSTMA President, Chris Crockett

From the MAGCSA President, Doug Estes

Calendar of Events

Index of Advertisers

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AUGUST/SEPTEMBER 2009 Email TTA at: tnturfgrassassn@aol.com

F R O M T H E T TA P R E S I D E N T Bob Hogan

Do Not Get

DISCOURAGED or DISAPPOINTED ast week, I spoke with one of our members, who said that he was very discouraged or disappointed in the way that our TTA had handled a certain opportunity. After giving a lot of thought to his concerns and even losing sleep over what he had said, it reminded me of an old story that goes like this. In ancient times, a king had a boulder placed on a roadway. Then he hid himself and watched to see if anyone would remove the huge stone. Some of the king’s wealthiest merchants and educated citizens came by and simply walked around the stone. They were too busy and too preoccupied with their own travels to help others. Many loudly blamed the king for not keeping the roads clear, but none did anything about getting the stone out of the way. Then a peasant came along carrying a load of vegetables. Viewing the situation, he decided the right thing to do was to move the stone for others to pass through easily. Upon approaching the boulder, the peasant laid down his burden and tried to move the stone to the side of the road. After much pushing and straining, he finally succeeded. As the peasant picked up his load of vegetables, he noticed a purse lying in the road where the boulder had been. The purse contained many gold coins and a note from the king indicating that the gold was for the person who removed the boulder from the roadway.

The peasant learned what many of us never understand. Every obstacle presents an opportunity to improve our condition. Life is full of stones to be moved. We in the turf industry should know this better than most. We move stones every day. I hope the following will help. First, make the decision to do something — move a stone. Take the time to plan the right way to get the job done. If others are to be involved, give them plenty of time to do their part, and don’t blame them for your poor planning. Life is

TENNESSEE TURFGRASS

more fun when you allow others to come alongside, even if it costs just a little more. Second, be responsible. Stay on the path you have chosen, and handle each situation. When you leave the roadway to bypass the boulder, the ditch is not always the easier route to travel. Third, do your best. All that anyone will expect is your best effort. Not everyone will like what you do and say, “Well done, my faithful peasant.” You may find a bag full of money under every stone, but chances are you will only find more stones to move. Let the stones fall where they may, and be proud of the job you have done when you give it your best. Fourth, play by the rules. The owner/manager (and even the king) wants things done his way, and that is OK. As your TTA board of directors, we are striving to do the right thing. We will continue to support ongoing programs in research, education and extension in the area of turfgrass management. Today, however, we are facing a financial stone, not a boulder, in the roadway. We are making the decision not to go around the problem but to remove it. We will continue to support board-approved activities that will be educational and profitable for TTA. As I said in my last letter, we will give it our best effort to make this association bigger and better. I hope and pray that every decision made by the board will increase our membership and trust in TTA. So, please help us make the TTA better, and start asking people to join and remind our old non-members to come back and renew their membership. You may never know who is watching you. It could be the King. If you have any comments or ideas about the TTA, the Conference & Trade Show or how we can increase revenue, please call me at The Hogan Company, 1-888-224-6426.

Bob Hogan, TTA President

AUGUST/SEPTEMBER 2009 Email TTA at: tnturfgrassassn@aol.com

The Official Publication of the Tennessee Turfgrass Association, the Tennessee Valley Sports Turf Managers Association and the Tennessee Golf Course Superintendents Association

Tennessee Turfgrass is the official publication of The Tennessee Turfgrass Association 400 Franklin Road Franklin, Tennessee 37069 (615) 591-8286 tnturfgrassassn@aol.com www.ttaonline.org Published by Leading Edge Communications, LLC 206 Bridge Street Franklin, Tennessee 37064 (615) 790-3718 Fax (615) 794-4524 Email:info@leadingedgecommunications.com Editor Mr. Bill Marbet TTA OFFICERS President Bob Hogan The Hogan Company (888) 224-6426 Vice President Jay Willis Glen Eagle Golf Course (901) 508-1986 Secretary/Treasurer Bob McCurdy McCurdy Farms (731) 692-3515 Past President Bill Francis The Ridges Golf & CC (423) 913-2276 Executive Secretary Mr. Jim Uden (615) 591-8286 TTA 2009 BOARD OF DIRECTORS Mr. Joel Beckham Mr. Dick Breedlove Mr. Paul Carter Mr. Doug Estes Mr. Thomas Garner Mr. Bill Marbet Mr. Scott McNeer Mr. Tommy Mittlesteadt Mr. Mitch Parker Mr. Scott Severance Mr. Doug Ward Mr. Sean VanHoose TTA ADVISORY MEMBERS OF THE BOARD Mr. Bill Blackburn Mr. Lynn Ray Dr. Tom Samples Dr. Dennis Shepard Dr. John Sorochan

FROM THE TVSTMA PRESIDENT Stephen C. Crockett, CSFM

TAKE ADVANTAGE OF NETWORKING OPPORTUNITIES through Your Memberships in TVSTMA and TTA vast amount of information and know-how can be gained through positive networking. As turf managers, we need to take advantage of our local meetings, as well as those at the state and national level. Through the TVSTMA, we have a strong local and regional network, with a great wealth of knowledge amongst the professionals within our state. Through sharing our knowledge, we can realize even greater opportunities. Networking should always be treated as a professional exchange; each new contact that you make through expanding your TVSTMA and TTA networks is an opportunity for both personal and career advancement. Through all of this, you may also find friends and build relationships that will last a lifetime. Support TVSTMA and TTA, and take advantage of the high level of networking that is available to you, even if only on the local scale.

Chris Crockett, TVSTMA President

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The Tennessee Turfgrass Association 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, Tennessee Turfgrass Magazine, or its editors. Likewise, the appearance of advertisers, or Turfgrass Association members, does not constitute an endorsement of the products or services featured in this, past or subsequent issues of this quarterly publication. Copyright ÂŠ2009 by the Tennessee Turfgrass Association. Tennessee Turfgrass is published bi-monthly. Subscriptions are complimentary to members of the Tennessee Turfgrass Association. POSTMASTER: Send change of address notification to Tennessee Turfgrass Association, 400 Franklin Road, Franklin, TN 37069. Postage guaranteed. Third-class postage is paid at Franklin, TN. Printed in the U.S.A. Reprints and Submissions: Tennessee Turfgrass allows reprinting of material. Permission requests should be directed to the Tennessee Turfgrass Association. 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 37064, (615) 7903718, Fax (615) 794-4524.

FROM THE MAGCSA PRESIDENT Doug Estes

We’d Love to HEAR FROM YOU! hot! That’s really all we need to say about the weather. I do hope that everyone can survive through the typical summer heat with few issues. This time of the year can be stressful and exhausting. We can look a little to the future and see that football season is not that far off. Camp Kiffin. The MAGCSA has been fortunate to experience a great start to our season. Each meeting thus far has produced great attendance and valuable information. We would like to thank all those involved in our prior meetings. We will take a month off for our meetings in August and resume back in September

It’s

with the Annual Scholarship & Research Tournament, which will be held at Memphis Country Club on September 28, 2009. Rodney Lingle will be the host superintendent, and everyone will be in for a great venue. We do encourage lots of support for this function, and we always welcome any TGCSA member. So, make plans in advance to make the trip over and be a part of supporting local universities and raising dollars for student scholarships. The associations that make up the Tennessee Golf Course Superintendent Association play an important role in our industry (MAGCSA, MTGCSA and ETGCSA). Each of these strives to give each member leadership, education and support. If you have not yet joined one of these associations, please make time to do so. Also, the Tennessee Turfgrass Association is another source of education, support and leadership. As a committee chair for the TTA website and membership, I can assure you that these areas are pathways to your own achievement. As stated by our president, we need your help and suggestions. The quickest solution for our membership is — join. Also, make early plans to attend this year’s conference and trade show. The officers and board of directors are planning for a great conference, and with your support, we can make a move in the right direction as we work towards 2010. Lastly, the association’s website is there for everyone. We would love your ideas, suggestions and experience. The website can be used for employment opportunities, equipment needs, research ideas and results, in-field experiences and education. We understand that everyone is busy, but take the time to let us know how we can serve you better and make this association the strongest it can be. Doug Estes Germantown Country Club 2009 MAGCSA President

CN OE VWESR F SRTOOMR YT H E T T A

By Wayne Ducote, Senior Sales Specialist, BASF Professional Turf & Ornamentals

TENNESSEE TURFGRASS

AUGUST/SEPTEMBER 2009 Email TTA at: tnturfgrassassn@aol.com

CONTINUED an industry pressured for cost savings, superintendents are considering every option, including going natural. These areas, called by many names (including native, natural and naturalized), can also help make a golf course more marketable during these difficult economic times, by providing increased aesthetic interest for golfers. Naturalized areas help create a contrast to intensely managed turf, and they improve wildlife habitat. While an aesthetic case for naturalized areas can be easily made, many superintendents are converting intensely managed turf to naturalized landscapes to cut their input costs related to fuel, fertilizer, irrigation, pesticides and labor. The deep root systems of these naturalized areas, for example, are more tolerant to environmental stresses and require less irrigation. Properly going natural, however, should not be confused with letting Mother Nature take over. Naturalized areas left to grow at nature’s will are bound to become large weed patches and over-grown eye sores that can become a no-man’s land for irretrievable golf balls. Unlike turf and groomed landscapes, a naturalized area’s success relies on a different type of plant management and a low-maintenance, but methodical, approach that includes both preemergence and postemergence herbicides.

Choosing plants and planning maintenance The types of plants that you choose for naturalized areas have a significant impact on maintenance needs. Monostands or mixes of fescues, lovegrass, bluestems, broomsedge, wheatgrass, indiangrass and others can provide a clean contrast to playable turf and require minimal maintenance inputs. They are great for sloped areas prone to erosion, and some varieties even have natural weed defenses. Native flowers and wildflowers add color to a course’s greenscape, but they require more care to ensure seasonal blooms and growth succession over invasive, aggressive weeds. When grown from seed, wildflowers may take up to three years to provide the impact desired. Some of the most popular choices for golf courses include cosmos, yarrow, baby’s breath, blackeyed susan, primrose, poppy and Shasta daisy, to name a few. Controlling weeds in a naturalized area inhabited by wildflowers can be a challenge for superintendents. Herbicides meant to knock down broadleaf weeds may also kill wildflowers, which are categorized as broadleaf species. As a result, these wildflower areas may require hand-weeding and spot spraying to remove unsightly broadleaf weeds. Grassy weeds, however, can be controlled with selective herbicides. If planting wildflowers, superintendents should consider the size of the planting area, realizing that these areas will require some hand-weeding to achieve the full benefits.

and then lightly till. Then use a low seed rate per acre to avoid thick stands of vegetation. Be sure to time seeding with seasonal rains to minimize the need for irrigation. With new areas, it is important to communicate progress to members, because plants may take years to develop and achieve the desired effect. One way to avoid waiting for the area to develop is to use established plants, if available. Plant them in the fall to make the most of favorable soil temperatures and decreased weed pressure. Superintendents could also cut costs by building an out-of-sight nursery to grow native varieties until they’re ready for planting. Mature plants should be spaced apart so players have room to walk in and play a missed shot back onto a fairway. A number of grass options — including lovegrass, fescues, broomsedge and bluestem — work well in these areas.

Managing weeds and promoting healthy, playable growth Seasonal thinning, trimming, mowing and spraying naturalized areas should be included in a golf course’s routine maintenance in order to sustain the integrity and playability of the course landscape. A management plan should start with an inventory of current herbicides in the chemical-storage building. Categorize your existing herbicides by application timing, use areas and weeds controlled (see chart on page 15). Note preemergence and postemergence herbicides, whether use sites are appropriate for wildflower areas and native grass areas, and their control of broadleaf weeds, sedges and grassy weeds. While many herbicide products labeled for golf-course use do not list native grasses and wildflowers specifically, language on the label usually allows you to evaluate the herbicide on your particular species. You should test the product on a small area to determine tolerance before making applications to larger areas. In addition, many product labels include native grasses and wildflowers that are tolerant to a particular herbicide in the ornamental section of the label.

Getting started on going natural Establishing strong, healthy plants is key for weed management in low-maintenance, naturalized areas. When beginning a new area, use a non-selective chemical treatment to eliminate weeds,

Consider mowing naturalized areas twice a year — once in the spring to provide for a clean, fresh growing season and then again in the fall before plants go into dormancy.

TENNESSEE TURFGRASS ASSOCIATION • TENNESSEE VALLEY SPORTS TURF MANAGERS ASSOCIATION • TENNESSEE GOLF COURSE SUPERINTENDENTS ASSOCIATION

This naturalized area features a monostand of ‘Aurora’ hard fescue, providing a visually pleasing textural and color contrast.

COVER STORY

TENNESSEE TURFGRASS

Preemergence herbicides should be the pillar of any naturalizedarea maintenance plan — using herbicides to preventatively control weeds will be your most cost-effective strategy. If you can prevent outbreaks with one application of a preemergence product each season, you’ll save yourself the time and expense of applying multiple postemergence products on multiple weed varieties. Spring and fall are ideal times to apply a preemergence herbicide to control weeds. Since most preemergence herbicides affect the roots of germinating weed seeds, they are generally labeled for use only on mature grasses with well-established root systems. Most preemergence herbicides labeled for golf-course use evolved from crop applications, which typically control tall and unsightly weeds commonly found in naturalized areas. These include grassy weeds such as barnyardgrass, foxtail, johnsongrass, panicum and witchgrass, as well as broadleaf weeds like lambsquarter, pigweed, spurge and smartweed. Postemergence broadleaf herbicides are effective on naturalized grass areas, but eliminating unsightly grassy weeds can be more challenging. There are several postemergence grass herbicides that can be used, but study product labels closely to determine if your stand is tolerant to the herbicide. Other strategies, such as mowing and thinning the vegetation, will promote healthy growth and keep the area playable. Consider mowing naturalized areas twice a year — once in the spring to provide for a clean, fresh growing season and then again in the fall before plants go into dormancy. After an area has been established for a few years, consider getting a permit for a controlled burn of the area. Scheduling an annual burn during the early spring months will encourage hearty growth and renew the soil. Once new growth appears, apply a preemergence herbicide before grassy and broadleaf weeds invade the area. Naturalized areas on golf courses continue to be a developing trend. And while they are not maintenance free, naturalized areas can reduce the amount of management required on the overall course and increase aesthetics. Properly managed naturalized areas can be mutually beneficial to superintendent budgets and player expectations. And when created and managed methodically, naturalized areas can give the golf course a visually appealing contrast to the manicured playing areas.

Maintenance Schedule Breakdown 1. Mow in the spring and apply a preemergence herbicide. 2. Monitor the amount of wildlife living in the naturalized area. If animals or insects have become pests to players, decrease the amount of food- and shelter-giving plants. 3. Spot-spray and hand-weed as needed if weed pressure increases during summer months. 4. Mow in the fall and apply a preemergence herbicide before dormancy hits. 5. If allowed, consider burning to clean out debris and vegetation to promote new growth. 6. If desired, label the indigenous grasses and flowers to both educate players and help remind maintenance crews which plants are intentional.

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CONTINUED Inventory Your Herbicides and Categorize Their Use in These Areas * Recommendations complied by BASF Professional Turf & Ornamentals’ technical staff. Disclaimer: Consult individual product labels to determine individual species tolerance. Most product labels allow users to evaluate species not on the label. User assumes all risk. This is a partial list of products and is provided as a guide.

Company Name Product Name

Active Ingredient

Preemergence — Grasses and broadleaves BASF Syngenta Dow AgroSciences United Phosphorus Inc. Amvac Chemical Corp.

Pendulum herbicide Barricade Dimension Surfian Dacthal

Pendimethalin Prodiamine Dithiopyr Oryzalin DCPA

Application Timing Preemergence Postemergence

Use Areas Native Grasses

Weeds Controlled

Wildflowers Grasses Broadleaves Sedges

X X X X X

X X

X X X X

X X X*

X X X X X X

X X

X X X X X

Postemergence — Non-selective Bayer Monsanto

Finale Roundup

Gulfosinate-ammonium Glyphosate

X**

Postemergence — Sedges BASF Gowan

Basagran herbicide Sedgehammer

Sodium Bentazon Halosulfuron methyl

X X

Postemergence — Grasses Drive XLR8 herbicide Acclaim Extra Segment herbicide Fusilade II

BASF Bayer BASF Syngenta

Quinclorac Fenoxaprop-P-ethyl Sethoxydim Fluazifop-P-butyl

X X X

X X X X

Postemergence — Broadleaves Dow AgroSciences Dow AgroSciences Multiple manufacturers Multiple manufacturers PBI Gordon LESCO

Turflon Lontrel Various Various Trimec Classic Three Way

PBI Gordon Dow AgroSciences

SpeedZone Confront

Triclopyr Clopyralid 2, 4-D Dicamba 2, 4-D + MCPP + Dicamba Dicamba + 2, 4-D + MCPP-P Carfentrazone-ethyl + 2, 4-D + Mecoprop-p + Dicamba Triclopyr + Clopyralid

Chart Guide: x* May be used in fine fescue x** Suppression

A naturalized area’s success relies on a low-maintenance, but methodical, approach that includes both preemergence and postemergence herbicides.

TENNESSEE TURFGRASS ASSOCIATION • TENNESSEE VALLEY SPORTS TURF MANAGERS ASSOCIATION • TENNESSEE GOLF COURSE SUPERINTENDENTS ASSOCIATION

T U R F TA L K

By Jim Brosnan, Ph.D., Assistant Professor; Greg Breeden, Extension Assistant; Tom Samples, Ph.D., Professor; Brandon Horvath, Ph.D., Assistant Professor; and John Sorochan, Ph.D., Associate Professor, The University of Tennessee

onosodium methanearsonate (MSMA) is an herbicide that is commonly used in warm-season climates. Since the 1960s, this product has been used to manage infestations of various crabgrass species (Digitaria spp.), as well as goosegrass (Eleusine indica) and dallisgrass (Paspalum dilatatum) in warm-season turf. MSMA, an organic arsenical herbicide, contains an organic form of the element arsenic. In its organic form, arsenic is relatively non-toxic. For example, the herbicide MSMA is far less toxic than aspirin. However, in an inorganic state, arsenic can be highly toxic. It is important to note that MSMA only contains organic arsenic. Furthermore, research has continually shown that MSMA is tightly bound to soil organic matter and is not readily leached. Water samples from two golf courses in Florida, however, tested high in arsenic in 2006. This spurred a ruling by (EPA) to cancel the registration of MSMA in all aspects of agriculture, including turfgrass management. There was a concern that organic arsenic from MSMA could convert into the more-toxic inorganic form in the environment. Multiple public comment periods followed the ruling, and the response from various facets of agriculture was overwhelming. The MSMA task force (an alliance of chemical companies that

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manufacture the product) and the cotton industry led the charge. Concerns were raised on a number of issues about the ruling, particularly that there was no way to conclusively say that the arsenic was from applications of MSMA. On April 22, 2009, the EPA announced the final decision regarding the use of MSMA for weed management. Impacts on the turfgrass industry are significant.

Turfgrass Restrictions Golf Courses Sales of all products containing MSMA for golf-course use will end on December 31, 2012. Any product remaining in storage after this date can be used until December 31, 2013. The EPA has not publicly commented on the fate of product remaining in golf-course maintenance inventories after this date. Until 2013, newly constructed courses will be allowed one broadcast application, and existing courses will be able to use MSMA only as a spot treatment, providing that spots are less than 100 ft2 and that no more than 25 percent of the course is treated within a given year.

Sod Farms Sales of all products containing MSMA for use on sod farms will end on December 31, 2012. Any product remaining in storage after this date can be used until December 31, 2013. The EPA has not publicly commented on the

fate of product remaining in sod-farm inventories after this date. Until 2013, two broadcast applications of MSMA will be allowed per season, and a 25-foot buffer strip will be required for farms bordering permanent water bodies.

Highway Rights-of-Way Sales of all products containing MSMA for use on highway rights-of-way will end on December 31, 2012. Any product remaining in storage after this date can be used until December 31, 2013. The EPA has not publicly commented on the fate of product remaining in inventories after this date. Until 2013, two broadcast applications of MSMA will be allowed per year, and a 100-foot buffer strip will be required when spraying near permanent water bodies.

Residential Turf, Commercial Turf and Sports Turf Maintenance Sales of all products containing MSMA for residential, commercial and sports turf use will end on December 31, 2009. Any product remaining in storage after this date can be used until December 31, 2010. The EPA has not publicly commented on the fate of product remaining in inventories after this date. Other uses that fall under this restriction include forestry, non-bearing fruit and nuts, citrus (bearing and nonbearing), seed production (bluegrass, fescue and ryegrass), drainage ditch banks, railroad, pipeline, utility rightsof-way, fencerows and storage yards.

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CONTINUED Dealing with the ruling This EPA ruling applies to all organic arsenical herbicides, which includes not only MSMA, but also disodium methanearsonate (DSMA) and calcium acid methanearsonate (CAMA). The loss of these herbicides will certainly make managing weeds in warm-season turf more difficult. Researchers are continually evaluating new compounds, as well as combinations of existing compounds, that will help soften the blow of this EPA ruling. To follow the latest turfgrass weed science research being conducted at the University of Tennessee, visit: http://tennesseeturfgrassweeds.org. Some turf managers have slightly less than two years to prepare for life after MSMA. Focusing on a few key principles may help make the transition easier.

1. Use the product while it is still available. Managers dealing with infestations of annual grassy weeds should use MSMA while it is still legal to do so. Make a diligent effort to control these weeds now,

and then shift your focus to preemergence control in the future. This point especially rings true for dallisgrass, as there are no options other than MSMA for selective postemergence control of this perennial grassy weed in turf. Herbicides such as foramsulfuron (trade name, Revolver) and trifloxysulfuron (trade name, Monument) will only provide dallisgrass suppression, not control. New chemistries, as well as combinations of existing chemistries, are being explored to provide selective dallisgrass control in both warm- and cool-season turf.

2. Establish effective preemergence practices. The loss of an effective, economical postemergence herbicide like MSMA renders preemergence control of annual grassy weeds more important than ever. When applied correctly, preemergence herbicides such as prodiamine (trade name, Barricade), oxadiazon (trade name, Ronstar), dithiopyr (trade name, Dimension)

and pendimethalin (trade name, Pendulum) can provide effective control of annual grassy weeds like crabgrass and goosegrass for extended periods of time. It is imperative that these materials be applied prior to the germination of weed seed and that they are watered in after application. Most labels require 1/2 inch of irrigation or rain-fall after application.

3. Make the most of cultural practices. The best defense against any weed invasion is a healthy, dense, vigorous turf stand. Implementing cultural practices (aerification, fertility, mowing, etc.) to maximize density will make turfs less susceptible to weed encroachment. For example, goosegrass thrives in compacted, poorly drained soils. Soils of this nature are commonly found in high traffic areas on sports fields where there is minimal turfgrass cover. Improving soil conditions in these areas by aerifying and topdressing will reduce the likelihood of a goosegrass infestation.

TURF TIPS

By Jim Brosnan, Ph.D., Assistant Professor; Greg Breeden, Extension Assistant; Tom Samples, Ph.D., Professor; and John Sorochan, Ph.D. Associate Professor, The University of Tennessee; and T.J. Serentis, Ph.D., Penn State University

lant growth regulators (PGRs) cause changes in turfgrass growth and development. The use of PGRs in turfgrass management has become increasingly popular in recent years. In addition to reducing mowing frequency, PGR applications also enhance growth characteristics and improve the ability of a turfgrass to cope with stress.

How do PGRs work? Turfgrass plants contain six hormones that affect growth and development. While each hormone plays a critical role in these processes, the majority of PGRs used on turfgrass target the biosynthesis of gibberellins. 20

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Two types of PGRs affect the expression of gibberellins in turfgrass plants. Class A PGRs are foliar-absorbed materials that inhibit the production of gibberellins near the end of the gibberellin biosynthesis pathway. Trinexapac-ethyl (trade name, Primo Maxx) is an example of a Class A PGR used regularly in turfgrass management. Class B PGRs are root-absorbed materials that stop the production of gibberellins near the beginning of the gibberellin biosynthesis pathway. Paclobutrazol (trade name, Trimmit) and flurprimidol (trade name, Cutless) are examples of Class B PGRs used regularly in turfgrass management. Depending on the use rate, these materials suppress vertical shoot growth by approximately 50% for either 4 weeks (Class A) or 6 to 8 weeks (Class B).

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CONTINUED Benefits of suppressing gibberellins Research has illustrated that there are numerous benefits to suppressing the production of gibberellins in turfgrass plants.

Mowing Suppressing the production of gibberellins leads to less vertical shoot growth and, in turn, less mowing. For example, applications of a PGR like Primo Maxx may allow an athletic field that is typically mowed three times per week to only be mowed twice. This reduces the amount of money spent on fuel, puts less wear and tear on mowing equipment and allows labor to devote time to other projects.

Color The lack of vertical shoot growth following an application of a PGR like Primo Maxx can also improve turfgrass color. With vertical shoot growth halted, the concentration of chlorophyll in leaf tissue increases, causing turf to exhibit a darker green color (see the photo on this page).

Density and rooting Applications of PGRs that suppress gibberellins cause carbohydrates produced during photosynthesis to be allocated to the lower portions of the plant (crown, stolons, rhizomes, roots). These carbohydrates provide energy to power the growth of these structures. For example, research conducted at Penn State from 2006–2008 reported that applications of Primo Maxx increased the total below-ground biomass (rhizomes and roots) of Kentucky bluegrass by as much as 8%. Research conducted in 2008 at The University of Tennessee reported that applications of Primo Maxx reduced the internode length of ‘Tifway’, ‘Riviera’ and ‘Celebration’ bermudagrass, consequently increasing shoot density. Increases in density can improve a turf’s resistance to divoting on golf courses and its ability to tolerate foot traffic on athletic fields. Increases in rooting can help turfgrass plants cope with biotic stresses like heat, drought and shade.

Heat and drought stress Suppressing the production of gibberellins prior to a period of heat and drought stress can improve turf quality when environmental conditions worsen. Research has reported that applications of Primo Maxx to ‘L-93’ creeping bentgrass (Agrostis stolonifera) improved both drought and heat tolerance. By reducing vertical growth prior to a 21-day period of 95°F temperatures, turf quality, chlorophyll content, photosynthetic efficiency, evaporative cooling and water-use efficiency were all improved. Those managing cool-season grasses like creeping bentgrass in the transition zone should consider using plant growth regulators prior to the onset of summer heat stress.

Shade stress In shady areas, turfgrass foliage tends to become pale and spindly as it grows vertically in search of light energy to be used in

photosynthesis. Gibberellins are needed in order for this etiolated vertical growth to occur. Suppressing the production of gibberellins with plant growth regulators can reduce the extent to which this occurs, consequently improving turfgrass quality in shade.

Weed control Certain PGRs can be used for weed control as well. Applications of paclobutrazol (Trimmitt) and flurprimidol (Cutless) have been reported to selectively remove annual bluegrass (Poa annua) from creeping bentgrass turf. Research at The University of Tennessee is currently evaluating annual bluegrass control programs involving PGRs.

PGRs are not perfect It is important to remember that PGRs help pre-condition turf for stress. They should not be used on turfgrass that is already under stress, specifically stresses such as heat, drought or traffic. Inhibiting the production of gibberellins during these stressed periods will limit recuperation and recovery. Additionally, do not use these products following cultural practices like aerification or in areas suffering from disease, as they may reduce the rate of healing. The timing of sequential applications is a key component to any PGR program. The effects of these products will dissipate approximately four to eight weeks after application. At this point, vertical shoot growth will surge rapidly. One study reported that Kentucky bluegrass growth increased 160% in the days following the end of growth suppression. To prevent this from happening, make sure that follow-up applications are made before the product begins to dissipate.

Conclusion There are numerous benefits to incorporating plant growth regulator applications in a turfgrass-management program. While the cost savings associated with reduced mowing are significant, the improvements in turfgrass rooting, tiller density, etc., that these materials provide can make dealing with stresses in the transition zone much easier. For more information on the use of PGRs in turfgrass management, contact your local extension agent, or visit http://tennesseeturfgrassweeds.org for additional information.

TENNESSEE TURFGRASS ASSOCIATION • TENNESSEE VALLEY SPORTS TURF MANAGERS ASSOCIATION • TENNESSEE GOLF COURSE SUPERINTENDENTS ASSOCIATION

I N D E X O F A DV E RT I S E R S

CA L E N DA R O F E V E N T S

Bayer www.bayerprocentral.com ....................................................9

August 3

ETGCSA Meeting Location: Black Creek Club

September 3

University of Tennessee Turfgrass Field Day Location: University of Tennessee, Knoxville, TN

September 14

MTGCSA Meeting Location: Stones River Country Club, Murfreesboro, TN

September 28

MAGCSA Scholarship & Research Tournament Location: Memphis Country Club

October 6

ETGCSA Scholarship & Research Tournament Location: Cattails at Meadowview GC, Kingsport, TN

October 26

MTGCSA Scholarship & Research Tournament Location: Old Natchez Country Club, Franklin, TN

October 29–31

Green Industry & Equipment Expo Location: Louisville, KY

Modern Turf, Inc. www.modernturf.com ........................................10

November 16

MTGCSA Meeting Location: Gaylord Springs Golf Links

Quali-Pro www.quali-pro.com................................ Inside Back Cover

December 2–4

29th Annual International Irrigation Show Location: San Antonio, TX

January 10–12, 2010

44th Annual TTA Conference & Trade Show Location: Marriott Cool Springs, Franklin, TN

January 12–16

STMA Annual Conference and Exhibition (Sports Turf Managers Association) Location: Disney’s Coronado Springs Resort & Convention Center, Orlando, FL

January 30–31

ANLA’s Masters in Landscape Business Management Program (American Nursery & Landscape Association) Location: Louisville, KY

BWI Companies, Inc. www.bwicompanies.com ..............................11 Covermaster Inc. www.covermaster.com........................................19 Dickens Turf and Landscape Supply www.dickenssupply.com.................................. Inside Front Cover Ewing Irrigation www.Ewing1.com.................................................. 3 Greenville Turf & Tractor, Inc. www.JohnDeere.com .......... Back Cover John Deere Landscapes www.johndeerelandscapes.com ..............19 Keeling Company www.keelingcompany.com ................................11 Mid Tenn Turf, Inc. www.midtennturf.com ........................................7

Sur-Line Turf, Inc ..........................................................................18 Syngenta www.syngentaprofessionalproducts.com ..........................7 Texas Sod Leasing www.texassod.com..........................................18 The Pond Lady www.thepondlady.com............................................ 8 The Turfgrass Group www.theturfgrassgroup.com ......................9, 17 Turf Mountain Sod www.turfmountain.com ....................................15 Winstead Turf www.winsteadturf.com ..............................................5

SAVE THE DATES! JANUARY 10–12, 2010 – TTA Annual Conference – & Trade Show

January 31– February 3 ANLA Management Clinic (American Nursery & Landscape Association) Location: Louisville, KY February 1–5

TPI Midwinter Conference (Turfgrass Producers International) Location: Kailua-Kona, Hawaii

February 8–12

Golf Industry Show and GCSAA Education Conferences Location: San Diego, CA

February TBA

TNLA Winter Education & Exhibits (Tennessee Nursery & Landscape Association) Location: Holiday Inn, Pigeon Forge, TN

Franklin, TN

TENNESSEE TURFGRASS

AUGUST/SEPTEMBER 2009 Email TTA at: tnturfgrassassn@aol.com