A Publication of the Turfgrass Council of North Carolina March/April 2021
HERBICIDE RESISTANCE
in Turf, Nursery And Landscape Ornamentals – Can it Happen on Properties you Maintain?
Member Spotlight on Eagle Award Recipient Cameron Stephens
The turfgrass industry has proven its resilience over and over, and when 2020 brought so many unexpected changes and challenges, you showed up to support each other and the organizations that bring turfgrass managers together. At Leading Edge Communications, we are proud to partner with the associations and companies that keep the industry and professionals growing.
To Our 2020 Advertisers
MANUFACTURERS OF…
Blue Colorant
Chelated 5% Iron
Chlorpyrifos 2.5% G
Chlorpyrifos Mole
Mole Cricket Bait
Defoamer
Latron B–1956
Methylated Seed Oil
Snail Bait
Soil Acidifier
Soil Wetting Agent
Soluble 10–30–20
Soluble 30–7–14
Soluble 20–20–20
Spreader Sticker
Surfactant for Herbicides
Tank Cleaner
Turf Green
Tweak
12–0–0–6% iron
GOLF COURSE SALES STAFF
Kieth Utt — West Central Florida (941) 809–1853
Jim Wells — West Central Florida (941) 720–2712
Bruce Bach — Southwest Florida (239) 989–9947
Roger Welker — East Coast Florida .............. (772) 260–0282
Kevin Downing — South Florida (561) 427–4501
Andrew Wampler — Western Carolinas (828) 674–2594
Bo Miller — Central North Carolina................ (704) 560–1852
Brandon Hicks — Central North Carolina (336) 906-0803
DISTRIBUTORS FOR…
AMVAC Andersons
Aquatrols
BASF
Bayer
BioSafe Systems Bioworks
Certis
Corteva Agriscience
FMC
Gowan
LebanonTurf
Milliken
Milorganite
Nufarm OHP
Old Castle PBI / Gordon
Quali-Pro Rightline
SePRO
Sipcam Agro
Solo
Sunniland
Syngenta
UPL
Yara
NC (828) 264-8843 Hendersonville, NC (828) 692-2233 Palmetto, FL (941) 722-3285
NEW and EXCITING PLANS
TCNC had its first (and hopefully the last for everyone’s sake) virtual annual meeting on January 21, 2021. The annual meeting went well considering it was our first event in the virtual world. Attendance at the virtual annual meeting was less than we had hoped for. However, we do understand many people are experiencing virtual meeting exhaustion and may have thought they couldn’t sit through another one.
We want to thank our sponsors for the event again and the members that took time out of their schedules to join us. Sponsors for the Annual Meeting and Education & Knowledge Series included Green Resource, Shennings Lawn Care, Southern Seeds Inc. and Quail-Pro.
TCNC presented our newly revised Strategic Plan initiative. This Strategic Plan will allow us to focus on what our members and the Board of Directors deem important.
We also had the first of four virtual Education and Knowledge Series events immediately following the annual meeting. Dr. Kathie Dello with State Climatologist of North Carolina and the Director of NC State Climate Office provided an excellent presentation on Weather Changes & Trends in NC.
We learned 2020 was North Carolina’s second wettest and the third warmest on record. Another noted reality was the increase in hurricane intensity. It can be difficult to predict weather patterns but thanks to scientists like Dr. Dello, we can get a good idea on where we could be in the future. The data we saw was very intriguing for our industry.
Mike Brown, a Leadership and Resource Consultant, was our second presenter for our virtual Education and Knowledge series on February 4th. It was an excellent interactive discussion on recruiting and keeping employees in the turfgrass industry.
TCNC has several new and exciting plans for the future which we hope to start rolling out in 2021. Thank you for being a part of The Turfgrass Council of North Carolina.
Kevin Herrmann 2021
North Carolina Turfgrass is the official publication of the Turfgrass Council of North Carolina 110 Horizon Drive Suite 210 Raleigh, NC 27615
919.459.2070
Fax 919.459.2075 www.ncturfgrass.org
EXECUTIVE DIRECTOR
Marcy Cottle
IMI Association Executives info@ncturfgrass.org 919.459.2070
Published by:
Leading Edge Communications, LLC 206 Bridge Street Franklin, TN 37064
615.790.3718
Fax 615.794.4524
info@leadingedge communications.com
TCNC OFFICERS
PRESIDENT
Kevin Herrmann Fairway Green Inc. Raleigh, NC
VICE PRESIDENT
Wilson Sutton Falling Creek Golf Club Kinston, NC
PAST PRESIDENT
Gene Queen Nature's Select Winston Salem, NC
TREASURER
Jonathan Richardson, NCCTP NCCTP Chairman Green Resource Dunn, NC
DIRECTORS
Brian Beane Nature's Select Premium Turf Services Winston-Salem, NC
Damon Dean
Keith Hills Country Club Lillington, NC
Andrew Wampler
Southern Ag Hendersonville, NC
You never get a do over when purchasing equipment. That’s why you need John Deere. Our fairway mowers bring meticulous consistency and precision to every pass. And thanks to our passcode-protected TechControl, you can lock-in every operators’ mower speed, turn speed and transport speed, so they hit the sweet spot every time. Learn more about the full line of John Deere golf turf equipment at Revelstractor.com or Finchinc.com
TCNC Deluxe Members
Companies wishing to support TCNC with multiple members can join as Deluxe Members. Deluxe Memberships can be purchased in one of three tiers: 1–5 employees; 6–10 employees; or 11+ employees.
If you'd like to learn more about the Deluxe Membership, please contact the TCNC office at (919) 459-2070 or info@ncturfgrass.org.
Thank You to Our
DELUXE MEMBER ORGANIZATIONS
The Biltmore Company
Barefoot & Associates Inc.
Buy Sod Inc
Carolina Farm Credit
Carolina Green Corp.
City of Raleigh
Parks & Recreation
Country Boy
Landscaping Inc
Fairway Green
Fayetteville Technical Community College
Givens Estates
Green Resource
JRM Inc.
Keith Hills
Country Club
Leap Frog
Landcare, Inc.
McConnell Golf LLC
Nature's Select
Premium Turf Services
North Carolina
A&T State University
Nufarm Americas, Inc.
Pennington Seed –ProTurf Division
Quality Turf
Smith Turf & Irrigation
Sod Solutions Inc.
Southern Ag Southern Seeds Inc
Town of Cary
Public Works
Turf Mountain
Sod Inc
Vandemark Farms LLC
Wake Forest University
CROP AND SOIL SCIENCES
Dr. Richard Cooper Professor 919.515.7600 rich_cooper@ncsu.edu
Emily Erickson Lecturer 919.513.2034 emily_erickson@ncsu.edu
Dr. Travis Gannon Assistant Professor 919.515.2647 travis_gannon@ncsu.edu
Matt Martin Extension Associate, Turfgrass 910675.2314 matthew_martin@ncsu.edu
Dr. Susana Milla-Lewis Associate Professor 919.515.3196 susana_milla-lewis@ncsu.edu
Dr. Grady Miller Professor & Extension Specialist 919.515.5656 grady_miller@ncsu.edu
Dr. Charles Peacock Professor 919.515.3667 charles_peacock@ncsu.edu
Dr. Rongda Qu Professor 919.515.7616 rongda_qu@ncsu.edu
Dr. Rob Richardson Associate Professor & Extension Specialist 919.515.5653 rob_richardson@ncsu.edu
Dr. Thomas Rufty Jr. Professor 919.515.3660 tom_rufty@ncsu.edu
Dr. Wei Shi Professor 919.513.4641 wei_shi@ncsu.edu
Dr. Fred Yelverton Professor & Extension Specialist 919.515.5639 fred_yelverton@ncsu.edu
ENTOMOLOGY AND PLANT PATHOLOGY
Dr. Terri Billeisen Extension Associate 919.515.7464 tlhoctor@ncsu.edu
Dr. Rick Brandenburg Wm. Neal Reynolds Professor 919.515.8876 rick_brandenburg@ncsu.edu
Lee Butler Extension Coordinator 919.513.3878 elbutler@ncsu.edu
Dr. James Kerns Associate Professor 919.513.4820 jpkerns@ncsu.edu
HORTICULTURE SCIENCE
Dr. Danesha Seth Carley Director, Southern IPM Center & Associate Professor 919.513.8189 danesha_carley@ncsu.edu
Justin Boggs Boggs Landscaping Statesville, NC
Chris Albright Southern Lawn Maintenance and Landscaping Winston-Salem, NC
Congratulations New NCCTP
Shaun Kerr Gates Four Golf and Country Club Fayetteville, NC
Calendar of Events
THURSDAY, MARCH 11, 2021
8:45 AM – 12:15 PM NCSU Aquatic Plant Management Workshop
THURSDAY, MARCH 25, 2021
6:00 PM – 8:00 PM
Online Private Pesticide Applicators “V” Training
Stay up-to-date with TCNC event throughout the year at NCTURFGRASS.ORG
WHAT EXACTLY IS EXPECTED?
By Neal Glatt, CSP, ASM
Knowing what success looks like is one of the most foundational needs we have at work. It often surprises people to learn that, on average, about half of all employees are not completely clear about what they’re supposed to be doing at work. Let’s explore why there is such a disconnect about expectations and how you can ensure your team is set up for success.
The first, and easiest, way to create clarity is around job responsibilities. Make a list of what you (or your direct reports) do on a regular basis. Start with a list of tasks and meetings, then consider areas of responsibility, and finally items that are required to be turned in to other people like time sheets, financial reports, or status updates. Then compare this list to the published job description. See all the discrepancies? It’s important that these get reconciled – either by rewriting the job description to be accurate or by modifying daily work to match the existing job description – in order to help set the tone for clarity around employee job functions.
The second area where we experience confusion on the job is in the arena of relationships. Who do I report to and who reports to me? Most organizations today are actually matrixed instead of hierarchical, meaning that we often work in teams and report to multiple people over the course of a week, month, or year. This is actually an advantage because matrixed teams can achieve more and be more successful than organizations which have a simple, silo chain of command. However, it naturally opens the door to confusion. Who helps with career planning, team conflicts, pay discussions, or process questions? It could be multiple people and they may not be sure.
Third, there are many cultural expectations, or “unwritten rules” which are definitely expected and rarely articulated. For instance, when I run meetings, I have an expectation that we have an agenda and begin and end on time. I don’t tolerate people showing up even a minute late and I’ll stop discussion in the middle of a sentence if we run out of time. When I work with a group, I share these expectations and ensure there is agreement. This way, there is never confusion about expectations, or the consequences for failing to meet them. Of course, my expectations may seem harsh to you if your work group, or your preferred style, is different. And that’s the point – the emotional expectations of how a team will function must be explicitly discussed and agreed upon because we all have different ways of working.
Now that it’s clear why, and where, there can be so much confusion about expectations on the job, it’s time to start fixing the problem. No matter your position, initiate both formal and informal discussions around expectations. It takes everyone on the team to engage and adjust to changes by having regular conversations to continually clarify what is expected of each person. But the research proves that teams who clearly know what is expected of them are more productive, cost-effective, and adaptive. And there is no easier way to increase productivity than through job clarity.
Neal Glatt, CSP, ASM is a managing partner of GrowTheBench.com – a leading provider of affordable online education, professional development and peer networking for green industry professionals. Contact Neal via email at Neal@GrowTheBench.com
— OVER 30 YEARS OF TRUSTED SERVICE —
Sports field, Park and Estate Mowers
/ Rough Finishing Mowers
MEMBER SPOTLIGHT ON CAMERON STEPHENS 2021 TCNC Eagle Award Winner
TCNC would like to congratulate Cameron Stephens on receiving the Eagle Award. Each year, our board chooses a turfgrass professional to recognize for their commitment to and achievement in the industry.
Cameron is a Ph.D. student at the University of North Carolina. His area of study is plant pathology, with his dissertation covering etiology, epidemiology, and management of take-all root rot on golf course putting greens. Previously, he earned his Master of Science in Agronomy from Penn State and his Bachelor of Science in agriculture at Ohio State.
Alongside his studies, Cameron currently works as a graduate research assistant on a variety of projects. He held the same position at Penn State while working toward his Master’s. He has worked as a teaching assistant at NC State and Penn State as well.
Throughout his educational career, Cameron has co-authored a number of articles for peer reviewed publications, peer reviewed plant disease management reports, industry publications, and extension publications. He has conducted presentations at universities and conferences as well. Add to that membership in industry organizations and volunteerism, numerous first and second place finishes in competitions, and even an athletic career at a varsity lacrosse player at Ohio State.
Cameron says of his future plans in turfgrass:
“Upon completion of my Ph.D. from North Carolina State University in May 2020, I aspire to pursue a career in the turfgrass industry for an agricultural chemical company. While I have primarily worked with the biology and management of pathogenic fungi in the turfgrass system, my mentors have always stressed the importance of engaging in a diverse set of research projects, leadership roles, and experiences. The work I have pursued in turfgrass disease management and pesticide environmental fate has provided me with a number of valuable skills that I can put into action to benefit the end-user. The experiences I have had over the years has shown me what I really enjoy doing and where I can make the biggest impact in the turfgrass community. Interacting with the end-users and customers to provide science-based solutions to practical problems is what I am most passionate about. Therefore, my future career plan to pursue a technical service position within industry fits my strengths and puts me in a position to interact with the growers, help address their unique issues, and improve a company’s team dynamic within the turf and ornamental markets.
I believe achieving my short-term goal of being a technical service representative, my experience working in three different labs throughout my academic tenure and holding various leadership roles would position me to be an effective team leader. I would instill a productive, energetic, and positive culture which would be reflected in the relationships we build with superintendents, sales representatives, and the R&D and marketing teams. My professional career goals are centered around making a positive impact within the turfgrass community by working to improve turfgrass disease and weed management through agronomics and innovative chemical control strategies. I am highly motivated and passionate to pursue these career goals in the turfgrass industry and will continue to broaden my experiences and knowledge along the way.”
TCNC wishes Cameron the best in these future plans, and congratulations on earning the Eagle Award.
Become a NC Certified Turfgrass Professional!
Fast Facts about the NCCTP The
North Carolina Certified Turfgrass Professional (NCCTP) program is a comprehensive program developed to enhance the technical competency of turfgrass professionals, while elevating their professional image, that of your business and of the turfgrass management industry. Administered by the Turfgrass Council of North Carolina, the NCCTP designation confirms your expertise in turfgrass management to prospective customers and your peers.
Reasons to Begin Earning Your NCCTP Designation Today
The NCCTP program increases and enhances your turfgrass industry knowledge, career, and business development through a course of study of in-depth coverage of the science of turfgrass management.
The NCCTP designation offers immediate confidence and credibility of turfgrass management practices to customers and prospective employers.
Promote and market yourself as a North Carolina Certified Turfgrass Professional.
• Use the NCCTP logo on your business materials.
• Use NCCTP pins, uniform patches, and vehicle decals.
• Your TCNC Member Directory listing is distinguished with the NCCTP logo.
We Are Partnered With The NC State Turfgrass Professional Short Course
The NC State Turfgrass Professional Short Course, a comprehensive turfgrass education program, is offered at select NC State Extension offices and at NC State University. This Short Course offers a full curriculum of the science of turfgrass management as well as Continuing Education Credits for NCDACS Pesticide and NCLCLB Landscape Contractors’ license holders, and it will help you prepare for the NCCTP exam.
This Short Course is recommended but not required to take the NCCTP exam.
Enrollment Requirements:
Hold a current TCNC membership. If not currently a member, go to www.ncturfgrass.org and click ‘JOIN NOW’ to join online or download an application.
Have a minimum of one full year of work experience in the turfgrass industry.
Agree to the Certified Turfgrass Professional Code of Ethics as detailed on the application form.
Submit:
• A current and valid NC Pesticide Applicators license
• A completed NCCTP application (current TCNC members may apply online).
• NCCTP Program Application: $150
• Self-Study Materials: $50
• Exam Fee: $50
Curriculum and Exam:
Curriculum covers nine core areas: Turfgrass Characteristics; Establishing Turfgrass; Soils & Nutrient Management; Cultural Practices; Pests & Integrated Pest Management; Pesticides & Plant Growth Regulators; Landscape Safety & Pesticide Use; Calculations & Calibration; Turfgrass Business & Economics.
Candidates have six months from the date of their enrollment acceptance to complete the NCCTP exam. Candidates have six hours to complete the exam and must score 80% or more on each section to receive the NCCTP designation.
Exams can be taken at the TCNC office in Raleigh during normal business hours, or arrangements can be made at your local NC State Extension location.
Exams will not be graded if any application information is missing or if TCNC membership status cannot be confirmed. Please allow two to three weeks for exam grading and reports.
Upon successful completion of the exam, candidates will receive communication with their results and either next step options or their graduation packet.
Maintenance Requirements:
Maintain a current TCNC membership as a means of demonstrating ongoing support for the industry.
Submit an annual $50 renewal fee, which supports the NCCTP program and related promotional activities. Designation year is the same as the TCNC membership year, from July 1st to June 30th.
Hold a current NC Pesticide Applicator’s License. Subscribe to, actively support and uphold the TCNC Certification Code of Ethics.
The NC Certified Turfgrass Professional designation (NCCTP), the NCCTP logo and related programs materials are the trademarked property of the Turfgrass Council of North Carolina and cannot be used without TCNC’s written permission.
For additional information, contact TCNC at (919) 459-2070.
NCCTP Certification Program ENROLLMENT APPLICATION
Name Phone Address City State Zip
TCNC Membership #*
Pesticide Applicator License #
QUALIFICATIONS / REQUIREMENTS
Please read the items below and check each one that is true for you.
MEMBERSHIP: I am now, or I am applying here to be, a member in good standing of the Turfgrass Council of North Carolina.
PESTICIDE LICENSE: I hold a current North Carolina Pesticide Ground Applicator License with subclass L, turf, and ornamental (or equivalent from another state).
EXPERIENCE: I have completed a minimum of one full year of turfgrass industry professional work experience.
EXAM: Upon acceptance into the program, I plan to complete my study and take the required exam within six months.
DUTY: I have initialed the following page of this application to show that I strongly support and willingly subscribe to the Certified Turfgrass Professional Code of Ethics, and I pledge to uphold the credibility and integrity of the program.
CONTINUING EDUCATION: I agree to successfully complete additional future curriculum materials or sections that may be required as a result of new technology or regulation.
Company Title
Supervisor Supervisor’s Phone
Supervisor’s E-Mail
Company’s Address
City State Zip
Work Experience
Describe your turfgrass industry professional work experience; one full year is required to apply.
NCCTP Application Fee: $150, Study Materials: $50, Exam Fee: $50, TCNC Dues (call for amount, based on date)
Check Number__________________ (payable to TCNC)
TOTAL $
Credit Card: AMEX Visa MC Discover Billing Zip Code
Credit Card #
Name on Card
By signing this application, I verify that all the information is true and correct, I acknowledge and assume full responsibility for the charges on this application, and I agree to honor and abide by the terms of this non-refundable payment.
Signature Date
CERTIFIED TURFGRASS PROFESSIONAL CODE OF ETHICS
Please read and initial each section below that you support and commit to uphold.
DUTY TO THE PUBLIC
I AGREE
I AGREE
I AGREE
I AGREE
I AGREE
Conduct service first and foremost with regards to the safety, health, and welfare of the general public. Provide service, recommendations, and information based upon honest experience, and scientifically accurate and factual knowledge.
DUTY TO THE ENVIRONMENT
Operate in such a manner to protect and preserve our environment. Use and monitor all equipment, products, and materials in a manner consistent with the label and safe for the environment.
DUTY TO THE LAWS OF OUR LAND
Abide by all laws and regulations affecting the turf industry and support the enforcement of these laws.
DUTY TO OUR FELLOW PROFESSIONALS
Refrain from the use of false, misleading, or deceptive marketing and advertising practices. Practice and insist upon sound business management practices. Maintain the highest standard of personal conduct to reflect credit and add stature to the turf industry. Recognize the importance of strong relationships within the industry. Abstain from untruthful debasement, or encroachment upon, the professional reputation or practice of another turfgrass professional.
DUTY TO THE ASSOCIATION
Participate in association activities and events to help further the profession. Abstain from any unfair exploitation of my association, industry, or profession.
By signing this Code of Ethics, I agree to follow the duties and intentions outlined above, and I commit to supporting and upholding these ethics with consistency and integrity.
Date
DIGITAL MARKETPLACE
WATER
— Functions, Flow and Forms —
By Tom Samples, Ph.D. and John Sorochan, Ph.D., Department of Plant Sciences
Itis estimated that water makes up about 71 percent of the Earth’s surface and that 96.5 percent of all the Earth’s water is salt water contained in the oceans. Only about an estimated 3.5 percent is freshwater, 69 percent of which occurs as ice in glaciers and ice caps. Slightly more than 0.7 percent or 8.6 million acrefeet of the Earth’s freshwater occurs as groundwater, rivers, lakes and streams.
Turfgrass industry professionals are very aware that a susceptible turfgrass, a favorable environment and a pathogen with the ability to infect plants are required before a turfgrass disease will develop, and that free water on leaves and optimum temperatures for a certain number of hours are required for most fungal pathogens to cause disease. For example, pythium blight, a common disease of coolseason turfgrasses during hot, humid weather, is especially problematic when the surface of turfgrass leaves remain wet for at least 12 hours, the daytime temperature is greater than 82°F and the night temperature remains above 68°F. Cottony white mycelium is often visible in the morning when the surface of infected leaves are wet after a night of rain or heavy dew.
CONTINUED ON PAGE 20
Pythium disease of tall fescue
Alan Windham, Ph.D., Department of Entomology and Plant Pathology University of Tennessee Institute of Agriculture
This article is intended to summarize how water functions and flows in a turfgrass plant.
Functions
Water is essential for seed germination and plant growth, and usually comprises 75 percent or more of the fresh weight of actively growing turfgrasses. Roots contain the least amount of water, and stems the most.
Water moves by way of diffusion from the soil solution into root hairs. Once inside turfgrass plants, water helps protect them from sudden changes in temperature.
Both organic and inorganic molecules including sugars and essential mineral nutrients move to plant cells in water. An estimated 1 to 3 percent of the total amount of water taken up by turfgrasses every day is required to support internal biochemical reactions in plant cells, and cell division and expansion.
Although this amount appears small compared to the total amount of water turfgrasses use, it is vitally important for plant survival. Without water, turfgrasses would not be able to convert sunlight into chemical energy by way of photosynthesis (6 H2O + 6 CO2 > C 2H 12O 6 + 6 O 2). Warm-season turfgrasses have a more efficient photosynthetic system than cool-season turfgrasses. Cool-season turfgrasses need about three times more water than warm-season turfgrasses to produce equal amounts of shoot and root tissue. As much as 600 pounds of water may be necessary to produce one pound of turfgrass dry matter.
The uptake of water is crucial for maintaining cell turgidity and tissue turgor pressure, and the turfs’ ability to tolerate wear and recover from the compressive forces of foot and equipment traffic.
Water is the source of pressure responsible for the unfolding of leaves and the movement of roots and rhizomes in soils.
Water Absorption
Soil
The oxygen level in soil pore spaces generally ranges from 0 to 21 percent while the level of carbon dioxide usually ranges from 0.03 to 20 percent or more. The water vapor content in soils may exceed 80 percent. A small amount of oxygen is dissolved in rain or irrigation water. Air is also drawn downward as water moves vertically through the soil profile.
As turfgrasses grow, the transfer of water within and among the soil, the plant and the atmosphere is continuous. Most water absorbed from soil takes place in the root hair zone just behind the root apex. The presence of root hairs increases the absorptive surface of the plant root system. The length of the root hair zone varies among turfgrass species, and is affected by the age of the roots and environmental conditions during root development. Root hairs live for only a few weeks before being replaced as roots expand and mature. Root hair numbers decrease with increasing soil moisture.
The amount of soil water absorbed by turfgrasses is influenced by root depth and number, the amount of plant-available water, the rates of root extension and transpiration, and the soil temperature.
Water is first absorbed at a shallow level and then at successively greater depths as the water supply is depleted. Some water absorption and translocation can occur through a dead root system.
Bermuda miniverde Pythium blight advanced
Plant leaf cell
Foliage
Water in either liquid or vapor form and some foliarly applied nutrients enter aerial shoots of turfgrasses through tiny (< one nanometer in diameter) cracks or transcuticular pores. However, water absorption from leaf and stem surfaces does not generally occur by way of stomates due in part to the presence of waxes. Foliar water absorption is usually more rapid in young rather than old leaves. The size of water droplets may range from 50 (fog) to 500 (extremely coarse) microns. The amount of water absorbed by foliage under ‘normal’ growing conditions is only a minor portion of the total amount of water absorbed.
Evapotranspiration
Evapotranspiration, or ET, is the process by which water is transferred from turfgrass plants and their surfaces to the atmosphere. It is composed of two actions: evaporation and transpiration. Evaporation is the physical process resulting in a change of water on a plant surface from liquid to vapor. Transpiration is the plant process during which water is evaporated through a series of openings on leaf surfaces called stomates. Sunlight triggers a carbon dioxide control system causing guard cells to expand and stomates to open, while darkness causes guard cells to shrink in size and stomates to close. The amount of water lost by evaporation from the surface of plants is minimal compared to that lost due to transpiration. The conversion of liquid water to water vapor requires 570 calories per gram of water (~259,000 calories per pound). Since energy consumed as water in liquid form vaporizes, evapotranspiration produces a cooling effect.
Environmental conditions including soil moisture, wind, sunlight (radiant energy), relative humidity (atmospheric vapor pressure) and temperature affect the rate at which moisture is lost from turf surfaces. The rate of ET is usually low during dark, cloudy days with high relative humidity, low air temperature and very little wind. Highest ET rates occur on hot, sunny days with low relative humidity and moderate to high winds. Fans may be installed along the perimeter of greens located on sites where air flow is restricted in an effort to improve transpirational cooling.
Transpiration
Stomatal Transpiration
Depending on turfgrass species, the stomatal density most often ranges from 1,000 to 6,000 per square centimeter on the lower leaf surface, and from 4,000 to 10,000 per square centimeter on the upper surface. Although stomates make up only two to three percent of the total leaf area, they are often responsible for as much as 90 percent of the total water lost to the atmosphere by transpiration. The exchange of oxygen and carbon dioxide occurs through open stomates. Water evaporates from the moist surfaces of mesophyll cells and water vapor moves into intercellular spaces before diffusing along a vapor pressure gradient through the intercellular spaces into the stomatal cavity and eventually to the atmosphere. The stomatal transpiration rate is a function of the vapor pressure gradient. A portion of water being transported from root epidermal cells to mesophyll cells of the stomates is diverted from the main transpirational stream to several types of specialized tissues depending where the water potential gradient exists.
Raindrops on tall fescue
Stomate
Xylem
Xylem is the primary water conducting tissue in turfgrasses and is continuous from the root hair zone of the roots through the mesophyll cells of the leaves. Water enters root hairs by osmosis and moves in xylem, diffusing through cross walls that may or may not be perforated. Eventually, much of it moves from leaves to the atmosphere through stomates as water vapor. A hydrostatic gradient develops between the evaporation zone of leaves and the water absorption region of roots. Water evaporation results in a decrease in the water potential of the mesophyll cells. This causes water in xylem to move toward the mesophyll cells. This ‘siphoning’ by which water in liquid form is pulled from an area where it is most plentiful to an area where it is less plentiful is referred to as transpiration ‘pull’. Transpiration pull causes water to diffuse from adjacent root cells into the lower regions of the xylem. Both tracheids and vessel elements of xylem are made up of non-living cells.
Cuticular Transpiration
Although the majority of transpirational water loss occurs through stomates, some is lost by evaporation through the cuticle of epidermal cells while stomates are closed. The cuticle is produced by epidermal cells and serves as a protective film covering. It consists of polymers of both lipids and hydrocarbons containing wax. The thickness of the cuticular layer has a major impact on the amount of cuticular transpiration.
Vascular Bundles
Vascular bundles are long strands of vascular tissue containing xylem, phloem and supporting cells. Vascular bundles of the turfgrass leaf contain the same type of xylem and phloem structure as that of the stem. Most of the veins of a leaf blade are made up of a single vascular bundle, while the leaf mid-rib may contain several vascular bundles. The arrangement of xylem and phloem elements in large veins resemble those of the stem. However, only a limited number of tracheids in the xylem, and very few phloem elements occur in smaller veins.
Phloem
Some water remains in turfgrasses and transports sugar in phloem tissue both upward (acropetal) and downward (basipital). Glucose, sucrose and fructose move from ‘source’ cells into companion cells directly adjacent to phloem sieve tubes. The movement of sugars into sieve tubes reduces the water potential and water is taken up from the xylem by osmosis, raising the pressure potential in the sieve tube. The differences in internal pressure drive the phloem sap along the sieve tube to ‘sink’ cells. As sugars move into sink cells, the water potential in the sieve tube increases and water moves by osmosis back into the xylem.
Phloem
Xylem
Snow
In addition to buffering turfgrasses from low temperature extremes and dehydration, a layer of snow also limits freezing and thawing of soils and soil heaving. Turfgrass plants may be lifted and roots exposed as soils heave.
Dew
Dew forms when the turf surface cools as a result of the loss of infrared radiation to a temperature lower than the dew point of the surrounding air. The relative humidity is 100 percent when the dew point and the temperature are the same. If the temperature drops any lower, condensation will result and water droplets will form. Dragging a hose over bentgrass turf on golf greens in the morning to remove dew is a cultural practice intended to help prevent dollar spot (Lanzia spp.), but can spread the disease if fungi are active.
Guttation Fluid
Under certain environmental conditions, water containing plant exudates (guttation fluid) may move through very small openings called hydrathodes located at the ends of uncut leaves. These exudates contain mineral salts, sugars, amino acids and other organic compounds. Drops of guttation fluid may also be the direct result of exudation from freshly cut leaves. Exudation usually occurs when environmental conditions cause rapid water absorption by roots and at the same time restrict transpiration. These conditions produce a rise in root pressure and an elevated turgor pressure at the leaf tip. Leaf exudation occurs most often during the night or early morning hours and is promoted by routine irrigation, high nitrogen fertility and close, frequent mowing. Warm days followed by cool nights also favor leaf exudation. Tip burn of leaves from a high solute concentration may result when droplets of guttation water evaporate or are reabsorbed by the leaf.
References
Beard, J.B. 1973. Water- Chapter 8 in Turfgrass Science and Culture . Prentice-Hall, Inc. Englewood Cliffs, N.J. pp. 261–312.
Turgeon, A.J. 1999. The Turfgrass Environment-Chapter 4 in Turfgrass Management (Fifth Edition). Prentice-Hall, Upper Saddle River, N.J. pp. 109–153.
Dew on bermudagrass
Frozen guttation fluid on bentgrass
Index of Advertisers
Amick’s Superstore 25 www.amickssuperstore.com
Buy Sod, Inc. ..................... Inside Back Cover www.buysod.com
Carolina Green Corp. 17 www.cgcfields.com
Carolina Turf Farms, Inc. 13 carolinaturffarms.com
Divots, Inc. ................................................. 17 www.divotssand.com
Revels Tractor Co. Inc. 7 www.revelstractor.com
Green Resource ........................... Back Cover www.green-resource.com
Greene County Fertilizer Co. 27 www.greenecountyfert.com
Kesmac 19 www.brouwerkesmac.com
Leading Edge Communications ........ Inside Front Cover, 34 www.LeadingEdgeCommunications.com
Mid-Atlantic STIHL 33 www.stihldealers.com
Modern Turf, Inc. 9 www.modernturf.com
Morgan Sand Company ............................. 26 morgansandco.com
NewLife Turf, Inc. 17 www.newlifeturf.com
Progressive Turf Equipment Inc. ............... 11 www.progressiveturfequip.com
Smith Seed Services 6 www.smithseed.com
Sod Solutions 5 www.sodsolutions.com
Southern Agricultural Insecticides, Inc. 3 www.southernag.com
Southeastern Materials 21 soematerials.com
Southern Seeds, Inc. .................................... 9 www.southernseedsinc.com
Southern Specialty Equipment 27 www.ssequip.net
Super-Sod 23 www.supersod.com
The Turfgrass Group 29 www.theturfgrassgroup.com
Turf Mountain Sod, Inc. 27 www.turfmountain.com
Vandemark Farms ...................................... 11 www.vandemarkfarms.com
HERBICIDE RESISTANCE
in Turf, Nursery, and Landscape
Ornamentals – Can it Happen on Properties you Maintain?
By Jeffrey Derr, Ph.D. and Adam Nichols, Virginia Tech
This article was originally published in Virginia Turfgrass Journal, July/August 2020.
Herbicide-resistant weeds in turfgrass, ornamental, and nursery crop commodities have been an increasing issue over the past 10 years. It has been a while since we have seen a new herbicide mode of action so we are primarily relying on herbicides developed 20, 30, 40 or more years ago. Until new herbicide modes of action are developed, the issue of herbicide resistance will increase.
Definition of resistance
First, some definitions here. When I say “Herbicide Resistance,” I am referring to weed species that used to be controlled by a given herbicide, but now are no longer controlled. This is different from weed species that were always difficult to control — we refer to these as troublesome or tolerant weed species. Examples of troublesome weed species would include species like kyllinga, wild garlic, wild violets, Virginia buttonweed, bindweed, poison ivy, and mugwort (wild chrysanthemum). These troublesome weeds can be controlled, but it may require higher application rates or repeat applications. For herbicide-resistant weeds, increasing the application generally has no effect, as the biotype often can tolerate many times the highest use rate.
How resistance develops
It is thought that in a population of a given weed species, there may be a few individuals that, through a genetic mutation developed resistance to an herbicide. The mutation may have been present before that herbicide was ever used on the property. Current thinking is that herbicide application does not cause the genetic mutation
that confers resistance, but that the mutations occur as a separate, random process. Often the herbicide provided a high level of control for the susceptible biotypes of that weed species. Repeated applications of that herbicide quickly control the susceptible biotypes, allowing the resistant biotype to spread through uninhibited seed production. If that herbicide is reapplied every year or so for say eight or nine years, the resistant population will increase until it is the dominant biotype. Over that eight or nine years, that herbicide will be less and less effective until it provides no control at all.
Examples of resistance in turf situations
There are certain weed species that appear to be prone to developing herbicide resistance, such as annual bluegrass (Poa annua). There are documented cases of annual bluegrass biotypes that have developed resistance to certain herbicides. In 2019, Ian Heap (International survey of herbicide resistant weeds, www.weedscience.org) reported that annual bluegrass ranks third among all herbicide-resistant weed species globally, with resistance to nine different herbicide sites of action. Triazine-resistant annual bluegrass has been detected in turfgrass, with simazine being the primary triazine used in turf (mainly used in bermudagrass), with specialized uses of atrazine in certain warm-season turf species. Adam Nichols and I documented triazine resistant annual bluegrass at a golf course in Virginia a number of years ago. We kept seed from that biotype and discovered that biotype was also resistant to Xonerate (amicarbazone). Simazine and amicarbazone both are photosynthetic inhibitors.
CONTINUED ON PAGE 30
Annual bluegrass biotypes resistant to the dinitroaniline herbicides have been identified in Tennessee, North Carolina, and Georgia. The dinitroaniline herbicide class incudes prodiamine (Barricade, others), pendimethalin (Pendulum, others) , oryzalin (Surflan, others), and trifluralin (Treflan, others), key turfgrass and ornamental herbicides. Annual bluegrass resistant to glyphosate (Roundup, many others) has been identified in Tennessee and Missouri.
Biotypes of Poa annua resistant to the sulfonylurea herbicides have been documented in Tennessee, Alabama, and Virginia.
The sulfonylurea herbicide class includes foramsulfuron (Revolver), trifloxysulfuron (Monument), flazasulfuron (Katana), rimsulfuron, metsulfuron (MSM, Manor, others), and rimsulfuron + metsulfuron (Negate), chemicals used to selectively control cool-season grasses in bermudagrass and certain other warm-season turfgrasses.
We have verified a biotype of annual bluegrass from a golf course that is resistant to the commonly used sulfonylurea herbicides in bermudagrass. The golf course had been using Monument yearly to control annual bluegrass but after years of use had noted reduced control. In this case, one would have to look at preemergence applications of chemicals like Barricade, Specticle or simazine, or use postemergence treatments of glyphosate or Kerb (pronamide).
Recently, annual bluegrass resistant to early postemergence applications of Specticle (indaziflam) was detected at several locations in the southern U.S. Of extra concern in that research was that one of those annual bluegrass biotypes that tolerated early postemergence applications of Specticle also tolerated postemergence applications of flumioxazin, foramsulfuron, glyphosate, metribuzin, pronamide, and simazine. So that biotype could tolerate six
different herbicide modes of action. How can one control such a biotype?
Recently, annual bluegrass biotypes have been identified in Georgia that exhibit differential susceptibility to protoporphyrinogen oxidase (PPO) inhibitors, which includes Ronstar (oxadiazon) and flumioxazin (SureGuard, others). Whether it is due to genetic variability in this species or some other reason, clearly annual bluegrass is prone to developing herbicide resistance.
Other weeds besides annual bluegrass have developed resistance to certain herbicides (Table 1). Goosegrass has developed resistance to Ronstar in Virginia and to the dinitroaniline herbicides in Tennessee. Lawn burweed in New Zealand and buckhorn plantain in Indiana has developed resistance to the synthetic auxins, so the problem is not limited to grassy weeds. Compressed sedge in Alabama has developed resistance to key sedge herbicides, including halosulfuron (Sedgehammer, Prosedge). Large crabgrass and smooth crabgrass have developed resistance to the postemergence grass herbicides, which includes Acclaim Extra (fenoxaprop), as well as sethoxydim (Segment) and fluazifop (Fusilade, Ornamec).
A concern I have is if crabgrass species in Virginia develop resistance to quinclorac (sold by itself under the name Drive, and as a component of combination products such as Q4 Plus, among others.) Quinclorac is the primary herbicide used for postemergence crabgrass control in turf situations and is one of the few postemergence options in bermudagrass. One of the studies we have been conducting at the research station is evaluating alternative herbicides to quinclorac for postemergence crabgrass control in bermudagrass. There are more alternatives to quinclorac for postemergence crabgrass control in cool-season turf.
Poa in bermudagrass
Table 1 lists resistant weeds reported from general turf areas to the weedscience.org website. It is not a complete list as some cases of resistance in turfgrass have not been reported to this website but it does an indication of the problem. These listings in Table 1 do not mean all populations of those weeds in
the states listed are resistant, just that resistance has been documented in at least one location in that state. As these weeds flower, mowers can move seed from one site to another. Seed can also spread through wind, soil or sod, moving the resistant biotype to new locations.
Herbicide resistance in the nursery and landscape maintenance industries
Despite substantial reliance on herbicides for weed management, herbicide-resistant weeds have generally been perceived to be less of an issue in the nursery crop and landscape maintenance industries compared with larger-acreage agronomic cropping systems. Annual bluegrass, common groundsel (Senecio vulgaris), horseweed (Conyza canadensis), and fringed (northern) willowherb (Epilobium ciliatum) have been reported to be herbicide resistant in nursery production in at least one country (Table 2). A majority of the reports are weeds developing resistance to the Photosystem II (PS II) inhibitors, such as simazine (Princep). Although simazine is commonly used in field nursery production, it is not used in maintenance of landscape ornamentals.
One weed that has developed resistance to glyphosate in Virginia and other states is horseweed, often called marestail. Resistance developed primarily due to the extensive use of glyphosate in agronomic crop production. Horseweed seed can blow a considerable distance in the wind, so it can spread from crop fields to nursery production areas, landscape beds, and non-crop areas.
Generally combinations of preemergence herbicides are used in nursery production and in maintenance of landscape ornamentals to broaden the spectrum of weed control. The herbicides being combined usually differ in their mode of action so applying such combinations helps to reduce the potential for resistance development. A common combination as an example would be combining Gallery (isoxaben), more effective on annual broadleaf weeds, with Barricade (prodiamine), more effective on annual grasses.
These two herbicides differ in their mode of action. Besides combinations of sprayable herbicides, there are quite a few granular formulations that contain two active ingredients. An example would be Snapshot, a combination of isoxaben and trifluralin. If herbicide-resistant weeds are present in nursery production areas, these biotypes could be spread to landscape beds through the planting of infested trees or shrubs. However, we do not have good information on the spread of herbicide- resistant weed populations from nurseries to landscape beds.
Preventing herbicide resistance
What can we do to prevent the development of herbicide-resistant weeds? One should rotate herbicide modes of action or look at tank mixes of herbicides with different modes of action. One does not need to do this every year, but maybe every three or four years. For
example, one could alternate use of a dinitroaniline herbicide like prodiamine with Specticle (indaziflam) or oxadiazon in bermudagrass turf on a golf course. Simazine could be alternated with flumioxazin at a tree nursery. Halosulfuron could be alternated with sulfentrazone (Dismiss) for yellow nutsedge control in woody landscape beds and in turf areas. Alternating between FreeHand and Snapshot would be an option in ornamental beds. Utilize both preemergence and postemergence herbicide where possible as these 2 groups generally have different modes of action. To use this strategy, one needs to learn how each available herbicide controls weed (their mode of action). Use nonchemical means of weed control in your control program. Hand weed plants that survive an herbicide application, thus preventing seed production. Clean equipment when going to other locations to prevent spread of weed seed. By following these suggestions, there is less potential for herbicide resistance to appear on properties you maintain.
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