Tennessee Turfgrass - April / May 2010 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 APRIL/MAY 2010

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

New Products for Weed Control during the Seeded Establishment of Cool-Season Turfgrasses

Applied Research — Tips and Tricks for Turfgrass Disease Diagnosis

Turf Tips — Transition Aids for Overseeded Turf

Cover Story

Applied Research

Turf Tips

D E PA RT M E N T S

From the TTA President, Jay Willis

From the TVSTMA President, Theo Lankford

From the ETGCSA, Jeff Rumph

Calendar of Events

Index of Advertisers

TENNESSEE TURFGRASS

APRIL/MAY 2010 Email TTA at: tnturfgrassassn@aol.com

APPRECIATION F R O M T H E T TA P R E S I D E N T APPRECIATION APPRECIATION APPRECIATION APPRECIATION APPRECIATION ello, everyone! I hope your spring is turning out to be a good one. I know I’m enjoying the warmer temperatures being outside. As I wrote to you in the previous letter, we went through one of the coldest winters we have seen in quite a while. Well, I had the privilege to host a site visit with Chris Hartwiger and Pat O’Brien from the USGA, plus 10 superintendents and a GM from the Robert Trent Jones Trail in Alabama. The visit was an educational format to see how we manage ultradwarf bermudagrasses here in the Memphis area, including a look at how the grasses held up to winter traffic and cold temperatures. The RTJ Trail is looking at the possibilities of converting some of their bentgrass courses over to an ultradwarf bermudagrass. This was definitely a good year to see how cold hardy they are and how they withstand traffic during the winter. So far, I’m very pleased with the health of our greens, but I have noticed small winter injury on some of them. This is the first time that we have had winter injury, and we expect these areas to be a good bit slower coming out.

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Since I have the responsibility to write this letter, I decided to use this avenue to tell you about what is on my mind at the current time. I titled the letter Appreciation, for the simple fact that I feel sometimes we take for granted what all we have around us. I have been thinking about this a great deal lately, with the economy and job market we face in our industry. When I talked with the superintendents from the RTJ Trail, I realized how fortunate we are to be able to get together with one another and share ideas. We have a lot to appreciate, having jobs in an economy like this, when you hear of golf courses closing the doors or filing bankruptcy coming out of a bad winter. It’s only natural to sit back and make sure you have made the right decisions in your life for you and your family. It makes you appreciate the job you have, and I think it makes some of us wake up and try a little harder at our jobs. The TTA board just recently had a board meeting and took a step back to realize how fortunate we are to have the support from The University of Tennessee turf team. When things run

Jay Willis

so smoothly for so long, it’s easy to forget who helps make it happen and what parts make the whole team. I guess what I’m trying to say is, let people know how much you appreciate what they do for you. Whether it’s your colleagues at work, the way your boss allows you to put family first, your loved ones that show you unconditional support or your peers that let you call them any time of the day to pick their brain or just to say hey. Without getting too sappy, the TTA board of directors wants to show its appreciation to The University of Tennessee turf team for all the years it has supported the TTA and its members. Also, I would like to show appreciation to all the vendors and members that are a part of this family we call TTA. Thanks for listening to me while I was on my soapbox, and I hope the next time I write you it will be hot and dusty! Sincerely, Jay Willis TTA President

APRIL/MAY 2010 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 Jay Willis Glen Eagle Golf Course (901) 508-1986 Vice President Bob McCurdy McCurdy Farms (731) 692-3515 Secretary/Treasurer Paul Carter Bear Trace at Harrison Bay (423) 344-6374 Past President Bob Hogan The Hogan Company (888) 224-6426 Executive Secretary Mr. Jim Uden (615) 591-8286 TTA 2010 BOARD OF DIRECTORS Mr. Joel Beckham Mr. Bob Elliott Mr. Doug Estes Mr. Thomas Garner Mr. Bill Marbet Mr. Scott McNeer Mr. Tommy Mittlesteadt Mr. Mitch Parker Mr. Chris Simon Mr. Doug Ward Mr. Sean VanHoose TTA ADVISORY MEMBERS OF THE BOARD Mr. Bill Blackburn Mr. Lynn Ray Mr. Jeff Rumph Dr. Tom Samples Dr. Dennis Shepard Dr. John Sorochan

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 ÂŠ2010 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 Nashville, 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) 790-3718, Fax (615) 794-4524.

FROM THE TVSTMA PRESIDENT Theo Lankford

CHANGES,

NOW

and

ON THE WAY

ello again, everyone! I hope spring has found everyone busy and with plenty to do. I believe we are in for an interesting spring season, given we just had the coldest winter in 30 years. Although I don’t believe that winterkill will be a major problem, some people think otherwise, but only time will tell. While we wait to see what our bermudagrass is going to do, let’s talk some TVSTMA. Our board is working hard to get dues in, schedule events, line up sponsors and accomplish many other things for this year. One highlight, as most of you have already seen, is our newsletter that comes to you via email. With this

TENNESSEE TURFGRASS

newsletter, you can register for upcoming field days and even get driving directions to the events. If you do not get this, please let one of the officers know. I am very excited for this year’s field days, as they are looking to be great for us all. There are going to be some changes to our Middle Tennessee meeting that I believe we will all appreciate. There will be more to come in the future about that. Our website is seeing some changes, as well. A job-posting page will be up any day now. Also, we will have links to past TTA magazine issues, along with links to our gold level sponsors. Speaking of the TTA magazine, I would

like to feature some of our members in the magazine. If you have a recommendation of someone or would like to be featured yourself, contact me or one of the other officers. Before I conclude this letter, I want to encourage everyone to attend a field day near you. Once again, many great topics will be discussed, plus you’ll have many opportunities to see the latest in equipment, tools and products that are available to you through our vendors. I hope to see you all soon. Theo Lankford 2010 TVSTMA President

APRIL/MAY 2010 Email TTA at: tnturfgrassassn@aol.com

FROM THE ETGCSA PRESIDENT Jeff Rumph, CGCS

NEWS FROM THE RIGHT SIDE OF TENNESSEE (righthand side, that is) pring is here, thank goodness, and the East Tennessee Golf Course Superintendents Association is looking forward to a great 2010. In my last article for the TTA magazine, I reviewed all of the 2009 meetings, but we had yet to award scholarships. Following the Scholarship and Research Tournament in October 2009 at Cattails at Meadowview Golf Course, ETGCSA was able to award three $1,000 scholarships to the following students:

Directors

Sean Elverd, The University of Tennessee

Schedule of Meetings

William Rasnic, The University of Tennessee Gabrielle Wilburn, Walters State Community College

Quinn Bender, Flowtronex, Knoxville, TN Joe Hill, ProSolutions, Alcoa, TN Chris Simon, Signal Mountain G&CC, Signal Mountain, TN

Jeff Taylor, White Pine, TN

Advisory Board Cory Blair, Rain Bird Golf, Atlanta, GA Marshall Brown, Link Hills GC, Greenvillle, TN Roger Frazier, CGCS Cattails at Meadowview GC, Kingsport, TN

April 27, Mocassin Bend GC, Chattanooga, TN Chad Malone, Superintendent

May 25, Gatlinburg GC, Pigeon Forge, TN Jeff Rumph, Superintendent

We have a hardworking board of directors that has put together an excellent slate of meetings. Below are our board members and schedule.

Officers President, Jeff Rumph, CGCS Gatlinburg GC, Gatlinburg, TN

Vice President, Bill Francis, CGCS

June 21, Ridgefields CC, Kingsport, TN Brent Maples, Superintendent

July 13, Warriors Path GC, Kingsport, TN David Cloud, Superintendent

August 17, Laurel Valley GC, Townsend, TN David Latham, Superintendent

October 5, Scholarship & Research Tournament Cleveland CC, Cleveland, TN Leslie Marlow, Superintendent

three sites that have never hosted a meeting. Moccasin Bend, Warriors Path and Laurel Valley are new sites for ETGCSA, and I have personally never played two of them. So, it will be fun for everyone, and hopefully educational as well. The S&R Tournament at Cleveland Country Club will be our 20th annual event. This is a great layout, and host superintendent Leslie Marlow always has the course in great shape. It should be another wonderful event. We have seen some interesting weather over the last few years. From extreme heat and drought in 2008, to a mild but wet 2009, to the winter of 2010, which was one of the coldest and snowiest that I can recall. What should we expect for the rest of this year? I think that the best thing to do is to expect the unexpected. We can all hope for mild weather and an improvement in our economy, but in the end, all we can do is the best we can do, each and every day. May you all have a very happy, healthy and prosperous year.

The Ridges G & CC, Jonesborough, TN

Secretary/Treasurer, Gary Weller Council Fire GC, Chattanooga, TN

TENNESSEE TURFGRASS

I am especially looking forward to this yearâ&#x20AC;&#x2122;s meetings because we have

Jeff Rumph, CGCS Gatlinburg Golf Course

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COVER STORY

NEW PRODUCTS FOR WEED CONTROL

DURING THE SEEDED ESTABLISHMENT OF COOL-SEASON TURFGRASSES

By Greg K. Breeden, James Brosnan, Ph.D., and Tom J. Samples, Ph.D., The University of Tennessee primary cool-season turfgrasses used in Tennessee are tall fescue (Festuca arundinacea), Kentucky bluegrass (Poa pratensis) and heat-tolerant Kentucky bluegrass (P. pratensis x P. arachnifera). Successful establishment of these grasses requires an investment of time, effort and funds. Considering that the failure to control weeds during establishment can compromise the short- and long-term success of any project, implementing a proper weed-control strategy is essential. Cool-season turfgrasses can be established from seed during the spring, summer and fall of the year; however, establishment during fall is recommended, as temperatures in fall favor cool-season turfgrass seed germination and growth. Additionally, weed and disease pressure tends to be lower during cool fall weather than other times of year, and irrigation requirements are also reduced. However, circumstances often require that cool-season turfgrasses be established during non-ideal spring and summer weather. For example, many home-construction projects require a lawn to be seeded in order to pass final inspection. In these situations, steps can be taken to mitigate weed problems.

The

Ensuring a successful establishment A dense, vigorous turf is less susceptible to weed encroachment than a sparse stand that lacks vigor. Certain cultural practices can be 12

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implemented to ensure the development of a dense stand of seeded cool-season turf that will resist weed invasion. These basic steps include: 1. Soil testing before planting, to determine soil pH, phosphorus and potassium content. 2. Tilling and leveling the area to be seeded, addressing any potential drainage issues. 3. Uniformly applying fertilizer and lime, according to the soil test recommendations. 4. Finish grading the area to be seeded. 5. Selecting a high-quality turfgrass seed, and applying it at recommended rates. 6. Rolling or lightly raking the soil after seeding to ensure sufficient seed-to-soil contact. 7. Managing soil moisture to prevent seeds from drying out during germination. 8. Mowing once shoots develop multiple leaves and the canopy reaches a height greater than the desired height of cut. Detailed information on the establishment of cool-season turfgrasses in Tennessee can be found at http://tennesseeturf.utk.edu.

Prior to establishment Controlling existing vegetation (perennial weeds, etc.) is a critical step in the seeded establishment of any cool-season turfgrass.

Apply a non-selective herbicide (e.g., Roundup Pro or similar) at 1 qt./a (1 lb. ai/a glyphosate) 7 to 14 days before tilling the soil. A second application may be required to control perennial weeds like bermudagrass (Cynodon spp.) or any other plants that recover from an initial non-selective herbicide application. Should a second application be required, allow at least 7 days before tilling soil. Considering that there are a limited number of selective herbicides available for perennial weed control, these non-selective applications prior to tillage are critical.

During establishment Weed management after seeding is another important component to successfully establishing a healthy stand of cool-season turfgrass from seed. Annual grasses like crabgrass (Digitaria spp., Photos 1 and 2), goosegrass (Eleusine indica, Photo 3) and foxtail (Setaria spp., Photo 4) are some of the most common and troublesome weeds present during spring and summer establishment of cool-season turfgrasses. Broadleaf weeds like carpetweed (Mollugo verticillata) and prostrate spurge (Euphorbia maculata) can also be problematic. Several herbicides exhibit excellent turf safety and weed-control efficacy during the seeded establishment of cool-season grasses such as tall fescue and Kentucky bluegrass. Herbicides recommended for grassy and broadleaf weed control during the seeded establishment are outlined on the following pages.

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Photo 1. Large crabgrass (Digitaria spp.).

Photo 2. Smooth crabgrass (Digitaria spp.).

Photo 3. Goosegrass (Eleusine indica).

Photo 4. Foxtail (Setaria spp.).

Table 1. Herbicide guide for spring and summer establishment of cool-season turfgrasses. Establishment Time

At Seeding

6 Weeks After Seeding (6 WAS)

12 WAS

Spring

Tupersan (12 lbs./A) or Tenacity (8 fl. oz./A)

Tenacity (8 fl. oz./A) or Drive (64 fl. oz./A) on broadleaf weeds as needed

Summer

Tupersan (12 lbs./A), or Tenacity (8 fl. oz./A)

Tenacity (8 fl. oz./A) or Drive (64 fl. oz./A) on broadleaf weeds as needed

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

COVER STORY Herbicides for grassy weed control during seeded establishment Table 1 is a guide for herbicide use during spring and summer establishment of coolseason turfgrasses.

Tupersan (active ingredient – siduron) Apply 12 lb./A of Tupersan at seeding for preemergence control of crabgrass and goosegrass (this herbicide exhibits no activity against broadleaf weeds). Both granular and sprayable formulations are available. Most cool-season turfgrasses exhibit tolerance to seedling applications of Tupersan. The residual activity of this herbicide is low, and multiple applications are required for extended control.

Tenacity (active ingredient – mesotrione) Apply 8 fl. oz./A of Tenacity for pre- and postemergence control of crabgrass, goosegrass and certain broadleaf weeds during

TENNESSEE TURFGRASS

the seeded establishment of tall fescue and Kentucky bluegrass. Tenacity will not control white clover. A sequential, postemergence application will be required for season-long crabgrass control in Tennessee. To improve efficacy, apply this herbicide with a non-ionic surfactant at 0.25% v/v. Susceptible weeds will turn white 7–14 days after treatment and will eventually become brown and necrotic. Tenacity can be applied to an array of different cool-season turfgrass species during most stages of establishment; however, this herbicide is currently not labeled for use on home lawns.

Drive XLR8 (active ingredient – quinclorac) Apply 64 fl oz./A of Drive XLR8 for postemergence control of crabgrass and selected broadleaf weeds, particularly white clover (Trifolium repens), during the seeded establishment of tall fescue. This herbicide will

not control goosegrass. If applications are needed during the first 28 days after seedling emergence (DAE), do not add methylated seed oil (MSO) surfactant to the spray solution, as the addition of MSO will increase the potential for seedling injury. During Kentucky bluegrass, perennial ryegrass (Lolium perenne) and fine fescue establishment, do not apply Drive XLR8 before 28 DAE.

Herbicides for broadleaf weed control during seeded establishment Buctril (active ingredient – bromoxynil) Apply 1-2 pt./A of Buctril, 2 to 4 weeks after seedling emergence, for control of many broadleaf weeds. This herbicide exhibits no grassy-weed activity. Most cool-season turfgrasses exhibit good to excellent tolerance to Buctril.

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COVER STORY

Quicksilver (active ingredient – carfentrazone) Apply 1-2 oz./A of Quicksilver, no sooner than 7 days after seedling emergence, for broadleaf weed control during seeded establishment. Repeat applications will be necessary for effective control. Most cool-season turfgrasses exhibit tolerance to seedling applications of Quicksilver

have been mowed at least twice. Applications during warm weather (>90ºF) should be avoided, due to the potential for injury to not only to the turf, but also to surrounding vegetation. Numerous products are available, with some containing additional active ingredients (e.g., 2,4-D + MCPP + dicamba) that offer a wider weedcontrol spectrum.

2,4-D Amine (active ingredient – 2,4-D)

Final thoughts

Apply 1.5-2.0 pt./A of 2,4-D amine for control of many broadleaf weeds during seeded establishment. This herbicide should be applied only to seedling turf stands that

The best time to establish a cool-season turfgrass is the fall of the year; however, herbicides are available to control annual grasses and broadleaf weeds when estab-

TENNESSEE TURFGRASS

lishing cool-season turfgrasses during spring or summer. A successful establishment during these non-ideal times can be achieved, but specialized efforts must be paid not only to weed management, but also to disease, irrigation and fertility management. Always refer to the product label for specific information on proper product use, tank-mix compatibility and turfgrass tolerance. For more information on turfgrass weed control, visit The University of Tennessee’s turfgrass weed science website at http://tennesseeturfgrassweeds.org.

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APPLIED RESEARCH

By Alan Windham, Ph.D., and Tom Samples, Ph.D., The University of Tennessee anaging turf diseases in the transition zone is a challenge, since turfgrass pathogens are active here nearly all year. Diagnosing diseases is part science, part art and part interpretation of the signs (fungal structures) and symptoms (patches, leaf spots, etc.) that appear on plants. A turf manager wanting to diagnose/ identify a certain disease needs to know the basics: • The host plant • The pathogens • Conditions favoring disease development • Basic use of a microscope • Being a good observer • Collecting an appropriate sample • An understanding that not every turf problem is caused by a plant pathogen

With this knowledge, you can get started with the process of disease diagnosis. Below are several tips and tricks to successfully diagnosing turf diseases.

Tip 1: Collect a good sample, and get it to the lab as quickly as possible. A general rule is to take a cup-cutter-size plug (about 4" in diameter) from the periphery of the patch of diseased turf. Small plugs taken with soil probes are essentially worthless for disease diagnosis. The plug 18

TENNESSEE TURFGRASS

should include healthy, as well as diseased turf (Photo 1). Wrap the plug in newspaper or a paper towel, and secure it with tape (Photo 2). Pack it carefully, and ship it overnight to the lab. Your contact information should include both street and email addresses and a phone number. Digital images of the symptoms on the green or in the field can be emailed to aid the diagnostician.

Tip 2: A digital camera can be used as a microscope to gather preliminary information. If you don’t have a microscope, but do have a digital camera with macro-mode for taking close-up shots, you can use it to spot fungal hyphae and fruiting bodies that may not be visible to the naked eye. First, set your camera on the highest resolution possible (5 megapixels or higher), engage the macro-mode and move as closely as possible to the plug while keeping the image in focus. Take the shot(s), and download them to your computer. By cropping and enlarging the area of an image from the affected area of the plug, you may be able to see hyphae and other structures that are not discernable otherwise. This works really well with some Rhizoctonia diseases without full-blown “smoke rings” of hyphae and with anthracnose of bentgrass where fruiting bodies are visible on leaf blades. For this tip to work success-

fully, you must take the image in bright light and have a steady hand or use a small tripod.

Tip 3: Use a moist chamber to make things “pop.” A moist chamber is a plastic box or bag containing a damp paper towel to raise the humidity level high enough to encourage fungal mycelial growth or sporulation (Photo 3). Collect a plug from the diseased turf in late afternoon, place it in a plastic storage box or bag with a moist paper towel and store at room temperature out of direct sun. Check the plug for fungal growth at 24 and 48 hrs. Moist chambers can sometimes be used to successfully confirm fairy rings. Not only will the top of the plug have abundant mycelium, but also mycelium may be growing out of the soil in the plug. It can be an impressive sight!

Tip 4: It’s not unusual to find more than one potential pathogen in a disease sample. This is where experience and the art of diagnosis kicks in. When I’m teaching classes on microscopic disease diagnosis, one key point is: “It’s not enough to find a fungal pathogen on a turf specimen. Ask yourself if that fungus is capable of causing the symptoms that are present on the turf?” A recent specimen from a lawn with large patch-type symptoms had Rhizocto-

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Photo 1. A plug for disease diagnosis should be pulled from the periphery of the patch and contain diseased and healthy turf. Photo 2. Wrap plugs with dry paper towels or newspaper and tape to secure. Pack carefully, and ship overnight. (Photo courtesy of H. Wetzel.) Photo 3. A moist chamber may be used to encourage fungal growth on a diseased plug. Photo 4. This specimen had both Rhizoctonia solani (Rs) and Gaeumannomyces (G) growing on infected leaf sheaves. Rhizoctonia was the primary pathogen. Photo 5. Pythium mycelium visible on bentgrass seedlings in early morning while dew and guttation water are present. Photo 6. Excessive mat in a bentgrass plug after washing sand from the root zone.

nia solani and Gaeumannomyces graminis var graminis growing side by side in the leaf sheath (Photo 4). The symptoms associated with the patches on the lawn indicated that R. solani was the primary pathogen.

Tip 5: Examine turf early in the morning, before the dew disappears, for signs of disease. The “smoke ring” of mycelium associated with brown patch on tall fescue is often most visible early in the morning. White mycelium associated with both dollar spot and Pythium blight (Photo 5) may also be visi-

ble in early morning when these diseases are active. It is always best to collect plugs for turf disease diagnosis when the fungus is most active.

Tip 6: Cultural problems can kill grass, too! Nearly one-third of all turf specimens submitted to our lab have no fungi associated with the symptoms. Excessive thatch, mat layers in greens, black layer and excessive irrigation may all cause significant problems. High levels of organic matter (Photo 6) and layering of sand and organic matter

from infrequent topdressing of greens may lead to saturated rootzones and very slow water infiltration. Wet greens and high temperatures in July and August can be a deadly combination. Poor water quality may also play a role in turf problems. Irrigating from a stream or lake with a high algae count can lead to an algal mat that can effectively seal the surface of the green and restrict the movement of water and oxygen into the rootzone. When examining the profile of a plug, it’s not unusual to see the best shoot growth and color and root growth associated with

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

APPLIED RESEARCH a vertical channel created during aerification and filled with sand topdressing.

Tip 7: Identification of leaf spot and other foliar diseases depends on observing the causal fungus. What appears as a nondescript browning, yellowing or thinning of turf may actually be the advanced symptoms of a leaf spot disease. Years ago, fungi in the group Helminthosporium were associated with leaf spot diseases and melting-out of turf. Recently, Helminthosporium has been split into Bipolaris and Drechslera. We see Bipolaris most often on bermudagrass (Photo 7) and Drechslera on cool-season turfgrasses. Itâ&#x20AC;&#x2122;s imperative to see the microscopic spores of each fungus for positive identification. Another leaf spot disease that can be extremely damaging on cool-season turf is

TENNESSEE TURFGRASS

gray leaf spot, caused by the fungus Pyricularia. This fungus usually sporulates heavily on diseased turf, making the diagnosis of gray leaf spot is less challenging. Rust is most often observed on bluegrass, ryegrass and Zoysia. Powdery mildew can be active during the winter months on bluegrass in shaded areas. Identifying rust or powdery mildew depends on observing orange pustules (rust) or white mycelium (powdery mildew).

Tip 8: Look for visual clues when identifying nematode damage on turf. Damage from nematodes doesnâ&#x20AC;&#x2122;t usually occur overnight. A gradual thinning or yellowing of turf indicates their presence. Besides foliar symptoms, root length and root morphology (such as galled roots) may indicate a problem. For example,

turfgrasses infected with root knot nematodes may have swollen or galled roots that may be visible with the naked eye or with the aid of a hand lens. Extremely short roots and/or clubbed root tips may be an indication of sting nematode damage. Taking a soil sample from the periphery of the affected area and having it assayed for nematodes is the best method of determining if nematodes are a problem.

Tip 9: Microscopy is key to turf disease identification. The morphological characteristics of fungal spores and hyphae are best observed with a compound microscope at magnifications of 100x, 200x or 400x. The microscopic nature of the fungal pathogens that attack turfgrasses may make accurate in-field diagnosis very difficult. Certainly, educated guesses can be made based on the turf

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CONTINUED species, time of year, recent weather conditions and cultural practices. However, the final piece of the puzzle that completes the pathological picture is the information provided by microscopic examination.

Summary Successful turf disease diagnosis starts with collecting a good sample, gathering as much information as you can, examining the specimen and interpreting the signs and symptoms in the field and on the specimen for a positive identification. For more information regarding turf disease diagnosis, please contact the UT Soil, Plant and Pest Center at 615-832-5850, or soilplantpestcenter @tennessee.edu, or at http://soilplant andpest.utk.edu.

Photo 7. Bipolaris sporulating on ‘Tifeagle’ bermudagrass (at left) and spores of Bipolaris cynodontis. (at right).

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

TURF TIPS

By James T. Brosnan, Ph.D., Greg K. Breeden and Tom J. Samples, Ph.D., The University of Tennessee ermudagrass (Cynodon spp.) is one of the most commonly used turf species in Tennessee. This species grows rapidly throughout the summer months, allowing it to quickly recuperate from the stresses of foot traffic common in hightraffic areas like athletic fields. However, as temperatures cool each fall, growth slows, and the turf canopy eventually turns brown as the plant enters winter dormancy (Photo 1). As a result, bermudagrasses are often overseeded in September or October with a coolseason turfgrass, like perennial ryegrass (Lolium perenne). Compared to dormant bermudagrass, overseeded perennial ryegrass will provide improved green color and superior aesthetic and functional quality during the winter months. On athletic fields, overseeded perennial ryegrass offers improved playing conditions compared to dormant bermudagrass (Photo 2).

Above, top to bottom: Photo 1. Dormant bermudagrass turf. Photo 2. An overseeded bermudagrass athletic field. Photo 3. Clumpy ryegrass infesting bermudagrass.

TENNESSEE TURFGRASS

Too long of a good thing Historically, older cultivars of perennial ryegrass could not withstand summer temperatures in Tennessee and would be naturally eradicated during early summer as temperatures increased. However, perennial ryegrass breeding efforts have led to the development of heat-tolerant cultivars that can per-

petuate during the Tennessee summer heat. This is problematic, though, as research has shown that bermudagrass needs approximately 100 days of growth — without perennial ryegrass competition — to provide maximum performance during the summer. The growth of heat-tolerant overseeded turfs will not be significant; most of these perennial ryegrasses will persist in a dormant state during the summer as dense clumps that are not only unsightly, but also are a potential safety hazard on athletic fields (Photo 3). In these instances, the persisting perennial ryegrass is commonly referred to as a weed, termed “clumpy ryegrass.”

Why use a transitioning herbicide? Clumpy ryegrass is more difficult to control than overseeded perennial ryegrass. While the reason for this difference is not completely understood, it is believed that plants undergo physiological processes when acclimating to increased summer temperatures that consequently render them less susceptible to herbicides used for control. A well-timed herbicide application in early spring should provide nearly 100% control of the overseeded perennial ryegrass within 21 days after treatment, while many of the same herbicides will provide only an average

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CONTINUED Figure 1. Control of overseeded perennial ryegrass and volunteer clumpy ryegrass in Knoxville, TN, in 2009.

Monument (0.56 oz./A) Revolver (17.4 fl oz./A) TranXit (2 oz./A)

Monument (0.56 oz./A) Revolver (17.4 fl oz./A) TranXit (2 oz./A) Perennial Ryegrass Clumpy Ryegrass

100

Control (%) at 3 weeks after application

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

TURF TIPS of 50% to 60% control of clumpy ryegrass during the same amount of time (Figure 1).

Applying a transitioning herbicide Turf managers who decide to overseed in the fall should be committed to chemically removing the overseeded perennial ryegrass in spring with a transitioning herbicide. In Tennessee, these transition aids should be applied sometime beginning in mid-April through mid-May. Numerous herbicides are labeled to chemically remove overseeded perennial ryegrass from bermudagrass turf (Table 1, next page). When choosing a herbicide, the desired speed of transition should be considered. Kerb and Manor (formerly marketed as Blade) are older products that tend to work more slowly than some of the newer sulfonylurea herbicides, like Monument. A slower response, however, does not mean that these herbicides are less effective. In general, warmer temperatures usually increase the speed of transitioning. Applications at soil temperatures lower than 50Â°F are not recommended, due to potential reductions in efficacy. Make sure to take extra precaution if applying transitioning herbicides on slopes or areas adjacent to sensitive cool-season turfgrasses, like creeping bentgrass (Agrostis stolonifera). Herbicides used to chemically remove perennial ryegrass have been shown to move offsite with not only surface water, but also with foot or equipment traffic. Maintaining buffer zones between treated and sensitive areas and removing dew with irrigation (< 1/8") the morning after application will help to prevent problems.

In summary Overseeding dormant bermudagrass with perennial ryegrass will improve turf color and quality during the winter months; however, overseeded perennial ryegrass must be removed with a transitioning herbicide in late spring to mitigate the problems associated with clumpy ryegrass infestations. Always refer to the product label for specific information on proper product use, tankmix compatibility and turfgrass tolerance. For more information on turfgrass weed control, visit The University of Tennesseeâ&#x20AC;&#x2122;s turfgrass weed science website at http://tennessee turfgrassweeds.org.

CONTINUED Table 1: Herbicides used to chemically remove overseeded perennial ryegrass turf from bermudagrass during spring transitioning Herbicide

Formulations

Active Ingredient

Rate/A

Comments

Certainty

75WDG

sulfosulfuron

1.25 to 2 oz.

Repeat applications may be necessary for complete control. Make sequential application when daily temperatures exceed 80°F. If a single application is preferred, apply at the 2 oz. rate.

Katana

25WG

flazasulfuron

0.5 to 3 oz.

Apply at 50% bermudagrass green-up for optimal maintenance of a green turf situation.

Kerb

50WP

pronamide

1 to 2 lb.

Manor

60WDG

metsulfuron

0.125 to 0.5 oz.

Repeat applications are often required for complete control.

Monument

75WG

trifloxysulfuronsodium

0.1 to 0.53 oz.

The lower rate allows for a more gradual transition. Higher labeled rates and warmer temperatures will result in faster removal.

Revolver

0.19SC

foramsulfuron

8.8 to 26.2 fl. oz.

Repeat applications (4- to 6-week interval) may be necessary for complete control. Higher labeled rates and warmer temperatures will result in faster removal.

Tranxit

25DF

rimsulfuron

0.5 to 2 oz.

Should not be applied in areas where children can contact turf. Repeat applications may be necessary for complete control.

Very slow, but effective. Highly mobile. Can slow bermudagrass green-up in spring.

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

CALENDAR OF EVENTS MAY 11 MTGCSA Meeting

JUNE 21 ETGCSA Meeting

Pebble Brook GC, Springfield, TN

Ridgefields CC, Kingsport, TN

MAY 17 MAGCSA Meeting

JULY 13 ETGCSA Meeting

Meadowbrook CC, West Memphis, AR

MAY 25 ETGCSA Meeting Gatlinburg GC, Pigeon Forge, TN

JUNE 2 TVSTMA Lower East Tennessee Field Day Lee University, Cleveland, TN

JUNE 14 MAGCSA Meeting

Warriors Path GC, Kingsport, TN

AUGUST 11 TVSTMA Upper East Tennessee Field Day

SEPTEMBER 20 MAGCSA Scholarship & Research Tournament

OCTOBER 28 – 30 Green Industry & Equipment Expo

Dandridge Parks & Rec., Dandridge, TN

Spring Creek Ranch, Collierville, TN

Kentucky Expo Center, Louisville, KY

AUGUST 17 ETGCSA Meeting

OCTOBER 5 ETGCSA Scholarship & Research Tournament

NOVEMBER 9 MTGCSA Meeting

Laurel Valley GC, Townsend, TN

JULY 19 MAGCSA Meeting

SEPTEMBER 13 MTGCSA Meeting

Windyke CC, Memphis, TN

Cleveland CC, Cleveland, TN

Hermitage GC, Old Hickory, TN

NOVEMBER 11 MAGCSA Meeting

Montgomery Bell GC, Burns, TN

Chickasaw CC, Memphis, TN

JULY 26 – 30 TPI Summer Convention (Turfgrass Producers International)

OCTOBER — MTGCSA Scholarship & Research Tournament

SEPTEMBER 16 University of Tennessee Turfgrass Field Day

Westhaven CC, Franklin, TN

Sheraton New York Hotel, New York, NY

University of Tennessee, Knoxville, TN

OCTOBER 18 MAGCSA Meeting

JANUARY 5 – 7, 2011 45th Annual TTA Conference & Trade Show

Tunica National, Tunica, MS

Fair Oaks GC, Oakland, TN

Marriott Cool Springs, Franklin, TN

ADVERTISERS Bayer.................................................................................11 www.bayerprocentral.com Covermaster, Inc.................................................................14 www.covermaster.com Dickens Turf & Landscape Supply.................Inside Front Cover www.dickenssupply.com Ewing Irrigation ..................................................................23 www.ewing1.com Gowan Company ................................................................17 www.gowanco.com Greenville Turf & Tractor, Inc. ........................Inside Back Cover www.johndeere.com Jackson Sand ....................................................................24 John Deere Landscapes .....................................................20 www.johndeerelandscapes.com KESMAC/Brouwer, Inc.........................................................25 www.kesmac.com Mid Tenn Turf, Inc...............................................................21 www.midtennturf.com Modern Turf, Inc. ..................................................................7 www.modernturf.com Quali-Pro .............................................................................3 www.quali-pro.com Sigma Organics, Inc. ............................................................7 www.sigmaturf.com Sur-Line Turf, Inc................................................................15 Tennessee 811 ..................................................................24 www.tnonecall.com Texas Sod Leasing..............................................................16 www.texassod.com The Pond Lady ...................................................................21 www.thepondlady.com The Turfgrass Group ..........................................9, Back Cover www.theturfgrassgroup.com Turfgrass America ..............................................................26 www.turfgrassamerica.com Winstead Turf .......................................................................5 www.winsteadturf.com

TENNESSEE TURFGRASS

APRIL/MAY 2010 Email TTA at: tnturfgrassassn@aol.com