green world AN INDUSTRYWIDE PUBLICATION OF THE NEW JERSEY TURFGRASS ASSOCIATION VOL. 14 No. 1 ABSTRACT: Factors Influencing Turfgrass Evapotranspiration (Colorado-1983). by C. M. Feldhake, R. E. Danielson, and J. D. Butler, Agron. J. 75:824-830. Turf was established in cylinders that were 25 cm in diameter and 25 cm in depth. The container mix was soil or a preparation of 80% sand and 20% peat moss by volume. The cylinders drained over gravel. Water use was replaced regularly through the week and recorded. Mowing height, nitrogen fertility, shading, grass species and soil composition effects on evapotranspiration (ET) were evaluated. Kentucky bluegrass (Poa pratensis L. var. “Merlon’) mowed 5 cm used 15% more water than grass mowed at 2 cm (0.8 in.). Thirteen percent more water was used when 4 kg 1000m2 of N was ap­ plied each month during spring and summer compared to only one ap­ plication for the season, applied In the spring. Evapotranspiration by grass in 1979 was essentially the same whether growing on a clay soil or on a sand-peat mixture; however, a 6% decrease occurred for the soil system In 1980. Evapotranspiration increased linearly with solar radia­ tion when an advective component of energy, accounting for 35% of ET, was subtracted from all solar treatments. continued page 6 If you are looking for another non­ contaminating, safe and effective weed killer, try a golf club! May/June 1984 FUNGICIDE USE STRATEGIES FOR LAWN CARE COMPANIES Dr. Peter H. Dernoeden Department of Agronomy University of Maryland Arriving at the decision of whether to apply a fungicide to any turf area is often difficult and generally based upon economic considerations. Aside from cost, the primary determinants in using a fungicide are the prevailing environmental conditions, host species and cultivars present, and the pathogen. The environmental factor has unique Implications In turfgrass pathology because the Intensity and nature of turfgrass management greatly Influences the environment and therefore the Incidence and inten­ sity of diseases. Diseases can seriously damage turfgrass plants and Impair the ap­ pearance of a lawn. Promoting vigorous growth through sound cultural practices Is the first step In minimizing disease Injury. Frequently, how­ ever, environmental stresses, traffic and poor management weaken plants, predisposing them to Invasion by fungal pathogens. When disease symp­ toms appear, It is Imperative that a rapid and accurate diagnosis of the disorder be made. The prudent manager also attempts to determine those factors that have led to the development of the disease. The most com- continued page 3 Figure 1. Dollarspot injury on Kentucky bluegrass. Note a bleached straw color of the dead leaves and stems. Comments Opinions and What is Turf’s Share of Nitrogen in the Environment? Ralph E. Engel The major part of earth’s nitrogen is in the atmosphere. Significant amounts from this great gaseous source are fixed at or near earth’s surface in a variety of substances (including our food and bodies). Synthesized nitrogen chemicals, precipitation, symbiotic nitrogen fixation involving higher plants, fix­ ation of nitrogen by soil organisms and auto exhausts are some sources of non-atmospheric nitrogen that occur at the earth crust. Among the synthesized ni­ trogen materials, fertilizer nitrogen is an important increment. Turfgrass, which uses only a small part of the U.S. fertilizer ni­ trogen, is sometimes considered dangerous and has been restricted in the New Jersey Pinelands as a ni­ trogen pollution danger. A little arithmetic indicates that turf fer­ tilization is not the common major source of nitrogen in the environ­ ment. While turf growing is a big dollar business, it does not occupy a large land acreage (even in New Jersey). The maximum rate of turf-nitrogen use is approximately 150 lbs N per acre per year. On the major part of the acreage, the rate will be in the range of 0-60 lbs per acre. This is scarcely the major source of nitrogen in our environ­ ment. My beloved and valuable wat­ chdog puts twice as much nitrogen in the area as my lawn. How does nitrogen in pet food stores compare with nitrogen in turf fertilizer usage? Lynn and Wilson (Advances in Agronomy 1950, Col. 2, pp 415) measured over 40 lbs. nitrogen ac­ cretion per acre per year on unfer­ tilized grass cover. Precipitation adds approximately six pounds of nitrogen on all of New Jersey acres of rivers, lakes, roads, fields and vegetation. The quantity of nitrogen emitted from autos is considerable, but totals are not unavailable. The various living and non-living sources of nitrogen in a soil will re­ lease nitrogen and will be as­ sociated with fixing and shifting forms through the more active parts of the growing season. Tests and analysts show 1500 to 7500 Ibs./acre of bacteria, similar quantities of fun­ gi, often a greater weight of non­ living organic matter, several hundred pounds of earthworms and other sources contain nitrogen that contribute to the dynamics of this element. The quantity and shifting of nitrogen forms from these sources dwarfs the amount from an­ nual turf fertilization. The amount of nitrogen that becomes soluble from these great natural sources are major factors which vary with the weather and the season. A turf sod is an environmental plus for the environment. It immo­ bilizes large quantities of nitrogen that water would carry through the soil. Grass sod holds great reserves of nitrogen which is maintained as a valuable resource for any subse­ quent food production that might occur on the site in later gen­ erations. Turf is a cover that can be used by people, and it serves to slow runoff of water which carries nitrogen and other chemicals into waterways and ground water. Turf growers have always desired and hoped to be friends of the en­ vironment. My previous comments are not intended to absolve turf of any responsibility. But I will not ac­ cept the coals of fire some would heap on turf until the actual balance sheet shows more about the origin and shifting of total nitrogen in our soil and water enviroments. I am suspicious of quotes on nitrogen loss studies, in which nitrogen fer­ tilizer is applied to turf, the nitrogen totals in the clipping and plant are subtracted from the total applica­ tion, and the unaccounted re­ mainder is called a soil-water con­ taminate. Such research interpreta­ tions should be replaced with studies that account for nitrogen losses in gaseous form and also consider the amount of nitrogen leaching that may occur on the natural or turf site without fertilization. Because of our environmental concern as turf growers and for the sake of efficiency, we should follow guidelines on nitrogen use that will minimize losses. By most com­ parisons, turf is not the source of a large portion of the total; but we can help by keeping the quantity for the growing year within the minimal range for each grass type until turf continued page 6 OFFICERS OF THE N.J.T.A. Dave McGhee, President Joe DeSantis, Vice President Ralph Engel, Secretary William Ritchie, Treasurer Dennis DeSanctis, Past President Henry Indyk, Expo Chairman EXECUTIVE BOARD Samuel Leon Joseph Dodgson John Zajac Joseph W. Manning, Jr. William H. Peterson Robert Dobson William A. Nist John Poksay Douglas Moody Green World is published three times a year by the New Jersey Turf­ grass Association, P.O. Box 231, New Brunswick, NJ 08903. Ralph Engel, consulting editor; Veronica M. Malone, managing editor. Please address inquiries concerning advertising to William Nist, Lebanon Chemical Co., Dayton, NJ 08810. (201) 329-4011 ABSTRACT: Urea and Urease Activity in a Kentucky Bluegrass Turf. 1983. by W. A. ToreIIo and D. J. Wehner, Agron. J. 75:654-656. Loss of nitrogen from volatiliza­ tion after nitrogen fertilizer applica­ tion has been studied frequently. Torello, Wehner and Turgeon showed a 10% loss with a high rate of prilled urea. At a normal rate of 49 kg N/Ha(approximately 1 lb N per M ft2) the loss with spray applied urea was 4.6% and was 1.6% from prilled urea. Previous study by others has shown great variability in nitrogen volatilization losses from urea. The role of the enzyme urease in the soil has received much study with regard to urea in the soil. Re­ ports of its stability at temperatures under 70°C and its dramatic in­ crease with greater amounts of organic matter stimulated the pres­ ent study on thatch effects on urea nitrogen and urease behavior. This study showed urease ac­ tivities were extremely high within the thatch and aboveground tissue compared with activity in the un­ derlying soil. This led to the conclu­ sion that applications of urea in wa­ ter or dry, where organic residue is abundant, offers greater risk of volatilization loss. Rinsing the urea into the soil was recommended to minimize this loss. Parkmaster The Professional for large areas. The Toro’ Parkmaster mows swaths from 30 inches to 18 1/2 feet wide -up to 80 acres a day. With a 7 or 9 unit hydraulically-controlled frame, it has a compact pattern of gangs for easy mowing, easy transporting The Parkmaster is the mowing tractor built to take Spartan ’ gangs Comes with powerful gas or diesel engine with cab and roll over protection system (ROPS) optional. TORO The professionals that keep you cutting Storr Tractor Co 3191 US Highway 22 Somerville. NJ 08876 201/722-9830 Fungicide Use Strategies continued from page 1 mon cause for extensive disease injury in lawn turf can frequently be re­ lated to poor management practices by the homeowner. Abusive practices include frequent and close mowing; light and frequent irrigations; and in­ adequate or excessive nitrogen fertility. The development of excessive thatch layers, shade, poor drainage and traffic also contribute significantly to disease problems in lawn turf. A good case in point is Helminthosporium diseases which are particularly damaging when turf is mown too closely, given light and frequent irrigations, and when turf is excessively fertilized. Despite hard work and adherence to sound management practices, diseases often becomes a serious problem. This normally occurs when environmental conditions favor disease development, but not plant growth and vigor. For example, Fusarium blight and brown patch are most damag­ ing when high summer temperatures stress plants and impair their growth and recuperative capacity. In this situation, fungicides may be recom­ mended in conjunction with cultural practices that promote turf vigor. Proper utilization and selection of fungicides is too difficult and compli­ cated for most homeowners. Because of this, only lawn care companies can provide the most reliable lawn disease service. Fungicides, however, should not become a part of a normal application schedule. As a general rule, use of fungicides is discouraged in most home lawn situations be­ cause (a) proper diagnosis and proper fungicide selection is difficult, (b) it is generally too late to achieve the economic and aesthetic benefits of a fungicide once extensive injury has occurred, (c) lawn care companies capable of only dry or granular applications do not have the proper spray equipment or they cannot obtain the desired fungicide(s) in granular form, and (d) it may be less expensive, and better in the long-run, to overseed a damaged turf area in the autumn with disease resistant cultivars. Where extremely high quality turf is desired fungicides will be needed in most years, particularly in the mid-Atlantic region. The indiscriminate use of fungicides or employment of numerous, preventative applications of fungicides for many diseases should be discouraged. Other than eco­ nomic restraints, reasons why repeated fungicide applications may not be desirable include: 1. Fungicides may reduce the population of beneficial microorganisms in the soil, which could lead to excessive thatch build-ups. 2. Fungicides may disturb a delicate balance among microorganisms that compete with and antagonize disease-causing fungi. This may explain why some diseases recur more rapidly and cause more in­ jury in turfs previously treated with fungicides. 3. Continuous usage of a single fungicide may lead to the development of fungal strains that are fungicide resistant. 4. A fungicide may control one disease, but encourage other diseases. 5. Possible phytotoxic or undesirable hormonal effects. When used repeatedly, certain fungicides have been shown to enhance thatch accumulation (1,2). Benzimidazole fungicides (e.g. Tersan 1991, Bromasan, and Duosan) and sulfur containing fungicides such as man- cozeb (Dithane M-45), maneb (Tersan LSR), and thiram (Tersan 75 and Spotrete) can cause thatch to accumulate by acidifying soil. The effect of these fungicides is indirect, that is, they inhibit the thatch decom­ position capacity of beneficial microorganisms by lowering soil pH. Cad­ mium fungicides and iprodione (Chipco 26019) also may enhance thatch accumulation. In the case of these latter two compounds, thatch build-up is attributed to direct toxicity of microorganisms that degrade thatch. Fungicides may also contribute to thatch build-up by being toxic to earth­ worms. Earthworms help reduce thatch by mixing soil with organic mat­ ter. Benomyl, mancozeb, anilazine (Dyrene) and chlorothalonil (Daconil) have been shown to be toxic to earthworms. continued page 4 A COMMENT ON “NO-MOW” GROUNDS Articles in the December 1983 issue on “no-mow” brought the reaction: why be concerned about the “no-mow” enthusiasts? The de­ sire for turf evolved over the ages and is so widely preferred that it will always be a part of the outdoor environment. My purpose for the articles was to provoke thought for those who might be sold “no-mow” landscape where it does not work and is not wanted. One of our county colleges provided a classic example of wasted dollars from inappropriate “no-mow” grounds and has now re­ turned to mowed turf. REE Time is Nature’s way of preventing everything from happening at once. Mystic KENTUCKY BLUEGRASS Mystic is so aggressive it rapidly fills in divot scars and fights Poa annua invasion making it ideal for use on golf course fairways and tees. It possesses the following characteristics: ★Tolerant of close mowing (3/4') ★ Provides a dense and aggressive turf ★ Resists Poa annua invasion ★ Fine texture ★ Bright green color Mystic was evaluated at Rutgers University by Dr. Ralph Engel and Dr. C.R. Funk under the experi­ mental designation P-141. For more information contact your local Lofts distributor, or Lofts Seed, Inc. Bound Brook, NJ 08805 (201) 356-8700 LOFTS Figure 2. Active dollarspot on Kentucky bluegrass. Note the cottony mass of mycellium. This disease may occur overnight, be inactive for a period of time or become active some days later with favorable moisture and temperature. Size of injured patches vary and may coalesce. Fungicide Use Strategies continued from page 3 Turf managers have observed that some diseases may recur in turfs previously treated with fungicides, but not in adjacent untreated areas. Dollar spot is probably the most common disease to exhibit this phenomenon. Data, recently recorded in a test conducted by the University of Maryland, have shown that red thread was more severe In the spring of 1983 in Manhattan perennial ryegrass plots last treated with benomyl in July, 1982. These phenonoma are attributed to non-target effects of fungicides, i.e. the fungicide(s) were toxic to microorganisms which an­ tagonize and help keep disease-causing fungi in abeyance. The development of fungal strains resistant to fungicides has been well documented. Resistant strains of the dollar spot fungus first developed as a result of repeated usage of cadmium based fungicides and benomyl on golf courses. Thiophanates (e.g. CL336, Fungo and Duosan), anilazine, and iprodione resistant strains of the dollar spot fungus have also been reported. Benomyl resistant strains of fungi causing Fusarium blight and powdery mildew, and iprodione resistant strains of the pink snow mold organism have also been reported. The development of resistant strains of fungi likely occurs in response to a selection process that eventually enables a small, but naturally occurring population of resistant biotypes to predominate in the fungicide-treated turfgrass microenvironment. Fungicides applied to control one disease may encourage other diseases. Tests conducted in Maryland have shown that benomyl and maneb can encourage red thread. Benomyl has also been shown to en­ hance Helminthosporium leaf spot, Pythium blight and superficial fairy rings. Thiophanate-methyl may increase crown rust in perennial ryegrass, iprodione can increase yellow tuft, and maneb may enhance dollar spot. In a 1983 University of Maryland test, three Kentucky bluegrass cultivars treated at monthly intervals with chlorothalonil were injured more severe­ ly by Fusarium blight, heat and drought stress than untreated turf. En­ couragement of disease in these situations may again be attributed to offsetting the delicate balance between antagonistic and pathogenic mi­ croorganisms in the ecosystem. It is also conceivable that some fungicides may physiologically alter the capacity of a plant to resist a particular patho- continued page 5 Wilfred Mac Donald, Inc. 340 MAIN AVENUE CLIFTON. NEW JERSEY 07014 201 471 0244 TURF EQUIPMENT SPECIALISTS Jacobsen National Giant Vac Cushman Kut Kwick Olathe Gravely Broyhill Burton Howard Smithco Bob cut Will pesticide use be regulated by fear or by Science? Fungicide Use Strategies continued from page 4 gen or withstand environmental stress. It should be noted that many of the harmful side effects just described were either Isolated events or occurred only after repeated use of one fungicide over the course of a year or more. Experienced turfgrass managers have long recognized that tank mixing fungicides and rotating fungicides greatly minimizes these potential problems. The Importance of rapid and accurate disease diagnosis, and the judicious use of fungicides are Integral In management programs. Fungicides may be applied preventively (I.e. before anticipated disease symptoms appear) or curatively (I.e. when disease symptoms first become evident). Applying a fungicide after the turf has been damaged significantly Is generally a waste of time, money and effort. Curative applications are more economical and environmentally wise. Many of these diseases are effectively controlled with curative fungicide applications when disease symptoms first appear. Once a disease has severely reduced stand density, fall overseeding with resistant cultivars Is normally suggested as opposed to use of fungicides. Also, repeated use of fungicides Is discouraged for reasons previously discussed. Contact fungicides are less expensive and provide good control. Con­ tact fungicides, however, may provide only 7-14 days of control under high disease pressure conditions. Where sudden and severe, or chronic disease problems occur, a systemic alone, or a systemic plus contact may be needed. Systemic or local systemic fungicides will provide 14-21 days pro­ tection during high pressure disease periods. Tank mixing a systemic plus a contact fungicide provides a longer residual effect and a wider spec­ trum of control. Frequently, a fungicide may only be needed to help the turf better survive a high pressure disease period. One lawn care company In Maryland provides fungicide treatments on an “as needed” basis without additional cost to the client. They estimated that only 5% of their customer accounts require a fungicide treatment. Of that 5%, only 10% require a second treatment In the same season. They use a specialist who Is trained to accurately diagnose turf diseases and to understand the Importance of the environment In disease causation and the relative susceptibilities of the turfgrasses to disease. In most situa­ tions what the homeowner believes Is a disease problem may actually be a cultural problem, or the disease Is Injurious because of poor manage­ ment practices. Normally, shifts In weather patterns to conditions that en­ hance turf growth and adherence to sound cultural practices will dramatically reduce and help minimize most lawn disease problems. In general, a single, or possibly two, properly timed applications will provide effective control of most disease problems encountered. Literature Cited 1. Joyner, B. G. and H. B. Couch. 1976. Relation of dosage rates, nutrition, air temperature, and suspect genotype on side effects of systemic fungicides on turfgrasses. Phytopathology 66:806-810. 2. Smiley, R.W. 1983. Compendium of turfgrass diseases. American Phytopath. Soc., St. Paul, MN. 102 p. COMMENTS: Dr. Dernoeden makes it clear that fungicides on lawn turf have both plus and minus con­ cerns. Along with this, he accepts the premise that we have reached the stage when more lawn fungicides may be appropriate in some specific situations. Considering the available good new fungicides and the desire for prime turf, where does this work begin? One occa­ sion is for high quality lawn turf that is suddenly attacked by dollarspot. Another occasion that may give valuable results is an applicaton on lush turf at the start of very hot wet weather that may persist for 5 to 10 days. A third occasion might be shade turf after vigorous growth and prolonged wet weather starts in mid- to late-spring. Follow Dr. Dernoeden’s suggestion of careful identification of turf injury. Also, as a professional, leave an untreated check strip occasionally for evaluation of results. In the meantime, use good management. Turf Nitrogen continued from page 5 need is demonstrated. Smaller and more frequent applications are usually more efficient than one large application. If this procedure with Its in­ creased application costs are too great or unfeasible, increase the percentage of slow release N. If rain does not follow application, apply a light rinsing with water from irriga­ tion to minimize fertilizer loss from the site. Observe your results and watch research for guidance on the most efficient weeks of the growing season for the best fertilizer re­ sponse of the given species. Also, manage to reduce turf failure which reduces the need for greater ni­ trogen use for turf reestablishment. Geologists estimate the world Is 5000 million years old and that 200 million years ago the current phase of continental drift started. It Is now known that the continents of Earth are still moving at the rate of be­ tween 3-5 cm per year. South African Panorama COUNTRY CLUB Professional Turf Products 18-3-12 70% 18-4-10 90% 18-5-9 50% Soluble Spray Grades SCU Blends PESTICIDES 25% 29-3-5 13-25-12 8-4-24 30% 20-8-8 50% 20-4-10 40% Special Mixes HERBICIDES LEBANON LEBANON CHEMICAL CORPORATION P.0. Box 180 P.0. Box 189 Dayton, NJ 08810 Lebanon, PA 17042 Sustaining Members Aabar, Inc. A-L Services, Inc. Aquashade, Inc. Blue Ridge Peat Farms Brickman Industries Brower Turf Equipment Burton Landscaping Chemlawn Corp. D & J Landscaping Double Eagle Equipment Co. DuBrow’s Nurseries Farmstead Golf and Country Club Florence Landscaping Svc. Inc. G & G Lawn Service, Inc. Garden State Goodall Garfield Williamson, Inc. Green Grass Lawn Maintenance Green Hill Turf Supply Hoffmann-LaRoche, Inc. Jade Run Turf & Sod Farm JEP Sales, Inc. Keystone Lawn Spray Leon’s Sod Farm Limestone Products Corporation Lofts Seed, Inc. A. Lombardi Landscaping MacAndrews & Forbes Co. Wilfred MacDonald, Inc. Metro Milorganite, Inc. Montco/Surf Side National Chemsearch Newton Country Club Rapp Sod Farms Reid Sod Farm Rockland Chemical Co. O. M. Scott and Sons Seacoast Laboratories, Inc. Somerville Equipment Co. Storr Tractor Co. Sweeny Seed Co. The Terre Co. Tuckahoe Turf Farms Turf Seed, Inc. Vaughan-Jacklin Corp. Andrew Wilson The supreme happiness of life is the conviction of being loved for yourself, or more correctly, being loved in spite of yourself. Victor Hugo Evapotranspiration continued from page 1 COMMENTS: The study gave good answers on water loss by évapotranspiration. The greater loss of water with the higher cut was not surprising be­ cause of the greater evaporating surface, but closer cut turf tends to give higher nitrogen plants with low­ er carbohydrate content which should increase water loss. The re­ sults suggest this was not the major influence on ET. While the study gives valuable information on fac­ tors that affect water loss, be care­ ful about applying the results for turfgrass survival. Greater rooting depth, rhizome development and soil depths are variables that in­ fluence survival; but were not in­ cluded in the study. So live that your friends can defend you, but never have to. Arnold Glasow FERTILIZERS COMBINATIONS OF NITROFORM I.B.D.U. S.C.U. And And WITH INSECTICIDES PRE-EMERGENCE CRABGRASS KILLERS HERBICIDES GRANULAR LIQUID SELECTIVE AND TOTAL FUNGICIDES GRANULAR FLOWABLE WETTABLE POWDERS INSECTICIDES GRANULAR LIQUID WETTABLE POWDERS Ask your supplier or write: ROCKLAND CHEMICAL CO., INC. Passaic Ave., West Caldwell, N.J.