/ CJilfSli;;!:^ - : Ninfe íMj ì'hj r» I, ! 'Î; J : !. < hl" , ' I I '''.'«'^«¡'.'¡llUíi I A :: : : V . : . ; { ft A * 1 0 E B i l if I m h JU's ií#!;Í1S ii Proceedings Of The 32nd Northwest Turfgrass Conference Sept. 26 - Sept. 28, 1978 Holiday Inn Richland, Washington PRESIDENTS MESSAGE By the time you read this, Northwest Turfgrass Association will have a new president Joe Pottenger. As I reflect back on my year as president, I see two areas in which the Northwest Turfgrass Association has made some real gains. The first is in the area of research. I believe Bob Wick's committee is functioning at peak efficiency and is a great credit to the Association. Secondly, I think NTA has made great strides in convincing the "powers that be" at Washington State University that turfgrass and the problems associated with turf are significantly important enough to warrant additional full time professional help to our industry. It has been a pleasure serving as your president. I wish the new President and Board a great deal of success and, of course, will be available to help as they deem it necessary. NORTHWEST TURFGRASS ASSOCIATION 1978 Officers Albert D. Angove President Joe Pottenger Vice President John Monson Treasurer Roy L. Goss Executive Secretary Board of Directors Albert D. Angove Director Parks and Recreation N. 811 Jefferson Spokane, WA 99201 Clayton Bauman Meridian Valley Golf Club 24830 - 136th Ave SE Kent, WA 98031 Carl Kuhn P. 0. Box 493 Mercer Island, WA 98040 Joe Lymp Golf Maint. Bldg. Sunriver Golf Course Sunriver, OR 97701 John Monson Broadmoor Golf Club 2340 Broadmoor Dr. E. Seattle, WA 98102 Earl Morgan Similk Beach Golf Course Rt. 2, Box 375 Anacortes, WA 98221 Joe Pottenger Suntides Golf Course 2215 Pence Road Yakima, WA 98902 Mark Snyder Salishan Golf Links Gleneden Beach, OR 97388 Bob Wick Capilano Golf & Country Club 420 Southborough Dr. W. Vancouver, BC, CANADA Tom Wolff Manito Golf & Country Club Box 8025, Manito Station Spokane, WA 99203 TABLE OF CONTENTS ^ C h e m i c a l Soil Amendments for Established Turf - Paul E. Rieke 7 \ S o i l Cultivation in Established Turf John M . Roberts 15 A Aquatic Weed Control - An Update R. D. Comes 23 Innovative Equipment - Larry Gilhuly 31 Maintenance Philosophies' Effect on Budgets - Bob Wick 33 Third International Turfgrass Conference M u n i c h , W . Germany - D. K. Taylor 37 Micronutrients in Turfgrass Management Paul E. Rieke 44 Purr-wick and P.A.T. Systems in Turfgrass Management - John M . Roberts 49 Gypsum for T u r f , Tree and Shrub Management - Donald H. Kocher 57 The Golf Course Superintendent: J o b , Image, 63 Association Member - Palmer M a p l e s , Jr H Pruning Landscape Trees David Hal stead 74 Research Report - D. K. Taylor 89 Slow-Release Nitrogen Studies - Idaho R. D. Ensign 94 Evaluations of Turfgrasses Under Idaho Conditions - R. D. Ensign 98 x Control of Poa annua in Lawn and Putting Turf in the Pacific Northwest Using Endothall - Tom Cook 103 Turfgrass Research Report - Alvin G . Law . . . . 113 Turfgrass Disease Research Report \ Gary A Chastagner 118 Growth Regulators on Established Turf John M . Roberts 123 A New Plant Growth Regulator with Potential Post Emergence Poa annua Control - John Roberts. 125 Overseeding Methods Following Endothall/Bensulide Treatments on Bentgrass Turf - John Roberts. . . 129 Nutrient Leaching in Sand Putting Greens John M . Roberts 132 Bentgrass Advanced Management Trials April 1 978 - Roy L. Goss 134 Other Research Currently Underway Roy L. Goss 138 Tolerance of Bluegrasses, Ryegrasses, and Fescues to Sulfur Applications Roy L. Goss 141 Slow Release Nitrogen Tests - Roy L. Goss 143 Sand Green Fertilizer Tests - Puyallup Roy L. Goss 145 CHEMICAL SOIL AMENDMENTS FOR ESTABLISHED TURFS 1 Paul E. Rieke2 This discussion is to deal with the nonfertilizer and non-pesticide chemical additives to the soil which could be used in turf management. The amendments to be considered are: 1) liming agents, 2) acidifying agents, 3) gypsum, 4) soil conditioners, and 5) wetting agents Many of the principles of soil management which apply to agricultural crops also apply very nicely to turfgrass soil management. But unlike most farmers the turf manager normally does not have the opportunity to mix chemical soil additives with the soil by plowing. This results in some unique situations for turf. Fertilizers and other chemicals applied to established turfs are left at the surface of the soil or in the thatch layer. Nutrients which are in a water soluble form (like nitrate nitrogen) can be readily leached down into the rootzone. Other nutrients, like phosphate, are much less soluble and are left at the surface. Gradually the applied material may move downward with water. Thus when using — To be presented at the 32nd Annual Northwest Turfgrass Conference, Richland, WA, September 25-28, 1978. 2/ — Dept of Crop and Soil Sciences, Michigan State University, East Lansing, MI. low solubility, persistent chemicals the turf manager must exercise caution to prevent a potential harmful buildup of the chemical in a concentrated zone near the surface. LIMING AGENTS The objective of liming is to raise the pH of an acid soil to a more desirable level. Most grasses grow well between pH 5.5 and 7.5 with the ideal range from 6.0 to 7.0. Above 7.5 some grasses exhibit micronutrient deficiencies, especially iron. Below pH 5.5 the effects of high acidity tend to reduce root growth. In very acid soils certain elements become highly soluble and can reach toxic levels for plants. Raising soil pH to reduce the toxic level of these elements is a practice which costs little and is easily practiced. Soil pH has a number of effects on soil and plants including affecting nutrient transformations in the soil, soil macro and microorganism activities, organic matter (and thatch) decomposition, development of toxic levels of certain nutrients, turfgrass rooting, and competition among the plant species in the turf. Obviously, soil pH can have a very significant effect on what happens in the soil and therefore, influences the management practices required. Since liming agents are applied to the soil surface the turf manager should be careful to note whether the lime recommendations are based on mixing the lime with a given depth of soil. Recommendations for liming agricultural soils often call for mixing the lime to a depth of 9 inches of soil or more. If the same rate of lime were applied to established turf a pH well above the desired range would result in the surface layer. Be sure your recommendations are made with established turf in mind. In selecting a liming agent one should evaluate particle size, speed of reaction in the soil, cost, magnesium content, ease of handling, whether the material is caustic, and purity of the material. A list of liming materials is given in Table 1. TABLE 1. Liming agents for turf. Liming agent Chemical composition Calcific limestone CaC0 3 Dolomitic limestone CaC0 3 .MgC0 3 92 Calcium hydroxide (hydrated lime) Ca(0H) 2 76 Calcium oxide (quick lime) CaO 56 Slag Variable Equivalent pounds* 100 Variable *Pounds of pure liming agent needed to attain the same pH change as 100 lb of calcific limestone. When applying liming materials if one desires a rapid pH change a finer grind of limestone is suggested (higher percentage of materials to pass through the 60 and 100 mesh sieves). If magnesium is low in the soil, dolomitic limestone is recommended if available. Our recommendation in Michigan is apply no more than 25 to 50 lb limestone/1000 ft 2 per year on established turf if the soil test shows lime is needed. Then the soil should be retested in a year or two to determine if more lime will be needed. Use of hydrated or quick lime materials is suggested only in unusual circumstances where rapid pH change is essential. These materials are hardto-handle powders and can be caustic. The slag materials vary widely in chemical content with variable content of magnesium, phosphorus, and manganese, among other nutrients, as well as in neutralizing value. Be sure you know the chemical content of the slag before using on turf. This is true for any liming material, of course. The cost and trouble to reestablish a turf make it imperative that only good liming materials be used and only when needed. Questionable materials should not be used even though they are cheaper. One means of applying liming agents which golf course superintendents have used is to mix the appropriate amount of lime with topdressing soil and topdress after coring. This allows some of the lime to be applied somewhat lower in the soil. In several parts of the country, liming agents are not needed because soil pH is naturally high or is increased due to irrigation with water high in bases. We have found a soil pH increase from 6.4 to 7.2 in a sandy soil after 6 years of intensive irrigation. Soil testing is the only dependable means of being sure of the need for pH adjustment. When sampling the soil under established turf conditions the depth of sampling is very important. Follow the recommendations of the laboratory which is conducting the soil tests. ACIDIFYING AGENTS In many areas soil pH is much higher than desired, leading to reduced availability of certain micronutrients, especially iron. Some turf managers are interested in reducing soil pH. Although means of reducing pH are available, the potential for turf injury from improper application is high. Any attempt to reduce pH should be approached very carefully. Acidifying agents include the use of acidifying nitrogen fertilizers, elemental sulfur, or possibly ferrous sulfate or aluminum sulfate. The latter two can be highly toxic to turf so I would not recommend their use to reduce soil pH with these materials. Ferrous sulfate is used, of course, to provide iron to the turf as a foliar treatment, but at much lower rates than are needed to lower soil pH. Acidifying nitrogen fertilizers include ammonium sulfate, ammonium phosphate, ammonium nitrate, urea, and any slow release fertilizer which forms ammonia in the soil. As the ammonia is nitrified to nitrate by soil microorganisms, hydrogen ions are released in the soil causing acidification. As an example of using acidifying fertilizers effectively, one superintendent in Michigan used ammonium sulfate on a green at the rate of 4 lb nitrogen/1000 ft 2 annually. After 3 years the soil pH in the 0-2 inch depth was 6.8; at 2-4 inches, 7.4; and at 4-6 inches, 7.6. In another study applying 14 lb nitrogen/1000 ft 2 annually to a loam soil over a 6 year period reduced soil pH in the 0-2 inch depth to 5.2, while it was 6.8 at 2-4 inches, and 7.4 at 4-6 inches. When such high rates of acidifying nitrogen carriers are utilized it is essential to test the soil more often to prevent developing serious pH problems in the surface layer. Using acidifying nitrogen carriers may not change pH, however. In another study ammonium nitrate rates as high as 16 lb nitrogen/1000 ft 2 annually for 7 years did not change pH because this was offset by irrigating with water drawn from a limestone acquifer. Throughout the study the soil pH remained at 7.5 to 7.7 on all plots. Each irrigation produced a "mini-liming". Elemental sulfur has been used effectively to lower soil pH, but must be used very carefully. A study was conducted on a silty clay loam bentgrass tee in Michigan. After 2 years the pH values shown in Table 2 were reached. Obviously too high applications of sulfur can result in drastic pH change in the surface layer with serious injury or death of the turf. In this study some injury occurred on the plots receiving 60 lb sulfur/1000 ft 2 in the one application. The turf did ultimately recover, but one could not risk such high application rates. TABLE 2. Soil depth inches Effect of elemental sulfur on soil pH two years after application. Sulfur rate, lb/1000 ft? 0 20 60 0-2 7.3 7.1 5.4 2-4 7.3 7.3 6.9 4-6 7.4 7.4 7.2 There are several different types of sulfur materials which could be applied to lower pH. These include crystalline, granular, powder, or sulfur mixed with complete fertilizers. The powder form reacts very rapidly so lower rates should be used per application. The large granular crystals may take more than a year to decompose and react in the soil. It is essential that the turf manager be familiar with the reaction of a given product in the soil before using that product on his turf. I like to encourage turf managers to do a little experimenting with such products on turf which is not necessarily visible to the public before adopting their use wide scale. It is wise to use no more than 5 to 10 lb sulfur/1000 ft 2 /application with the 5 lb rate being preferred. Applications could be made spring and fall with a maximum of 10 to 15 lb/year. It may take several years to lower pH, but it is better to be cautious. Sulfur applications should only be made during non-stress periods, such as spring and fall. Do not lower pH on turf where calcium arsenate has been used in the past for annual bluegrass control. If the soil becomes quite acid, the arsenate becomes more available and serious turf loss could occur. As more sophisticated systems are developed for fertilizer injection into the irrigation water, there arises the possibility of injecting acid into the water for lowering soil pH. I would not recommend this practice unless you very carefully check to be sure that the proper rate of acid is being applied and that the irrigation system will tolerate the acid. GYPSUM For soils high in exchangeable sodium (sodic soils), gypsum (calcium sulfate-CaSO^) has been used effectively to replace the sodium on the soil cation exchange sites. The sodium can be leached as sodium sulfate. Good drainage and excess irrigation water (or rainfall) are needed to move the sodium well out of the rooting zone. When this occurs there can be a dramatic improvement in soil physical properties resulting in better turf. There has been a suggestion that gypsum can be used to improve the physical properties of fine textured, non-sodic soils under turf conditions. This should be evaluated carefully. Few of our fine-textured soils in Michigan have appreciable exchangeable sodium. Most of them contain free lime with pH values above 7.0. Exchangeable calcium values of 5,000 to 10,000 lb/A are common. Applying gypsum to these soils has had no effect on soil physical properties in our studies. Check your sodium levels by soil testing to determine the need for gypsum. SOIL CONDITIONERS There has been occasional interest in the use of soil conditioners for improving the physical properties of turf soils. Although there is some promise with the use of such materials there are many problems to be solved as yet, so soil conditioners cannot be recommended for turf at this time WETTING AGENTS Localized dry spots can be a deterrent to main taining a beautiful, uniform turf. There can be a number of causes of localized dry spots on turf. One of these is the development of a hydrophobic condition on sandy soils. Water does not penetrate into such soils, but runs off to adjacent areas. Suggested solutions to the hydrophobic soil problem are to use wetting agents and cultivation, primarily by coring. We have had a series of studies on a hydrophobic sand in northern Michigan. There was considerable variability among the wetting agents studied in terms of their ability to bring about rewetting of the hydrophobic sand. The most effective among the group studied was Hydro-Wet, followed by Aqua-Gro. Other materials had to be used at considerably higher rates to achieve even some rewetting. Wetting agent treatment responses varied from one application date to another so repeat applications in the same growing season were found to result in the most consistent responses. The localized dry spot problem tended to recur from one year to the next. It is important to identify areas which are prone to the problem and treat early in the season to prevent serious development of the hydrophobic condition. Treatments applied in July and August sometimes did not result in turf recovery until the next spring even though the soil was rewet by the treatment the first year. Wetting agents should also be used carefully since they can cause injury to the turf, especially if treated during heat or moisture stress periods. Treatments should always be watered in to aid in moving the wetting agent into the soil and to reduce the potential for phytotoxicity to the turf. SOIL CULTIVATION IN ESTABLISHED TURF 1 John M. Roberts2 The benefits and principles of cultivation under sod have been repeatedly discussed and several observations and opinions have been formed by turf managers regarding the practice of cultivation. In particular, questions regarding the frequency and timing of cultivation, the influence of cultivation on the turfgrass vigor and subsequent weed invasion, and the effects of cultivation on soils having compacted surfaces have been of concern. Most of the cultivation research under sod has been conducted on soils having compacted soil surfaces. However, what about cultivation (Greensairing) on those soils which a) do not have a thatch problem, and b) have a desirable surface soil structure? In the field some turf managers will cultivate the soil regardless of its physical condition in the spring and/or fall of the year to retard compaction and reduce the organic layer that can accumulate under sod. However, the desirability of this practice on well structured soils is still a question among turf managers. In this study annual and monthly cultivation frequencies were made using a Ryan Greensaire (aerifier) on two well structured soils having a desirable organic layer thickness (1.0 cm) in the surface. The Ragsdale soil, having a silty clay loam texture, had an established Merion bluegrass sod while the medium textured sand root zone had a vigorous Evansville bentgrass sod. The soil cores removed by the — To be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, WA, September 25-28, 1978. 2/ — Turfgrass Research Associate, Western Washington Research and Extension Center (WSU), Puyallup, WA. Greensaire were shred by a vertical mower and returned to the test plot. Some of the physical changes in the soil structure in and below the tine penetration depth (7.6 cm) are reported. It is interesting to note that while there was some loosening action of the soil particles in the zone of cultivation (Table 1) impaired water infiltration rates on the Ragsdale soil following cultivation (Table 2) were recorded. This rather unexpected result was attributed to the (sealing) of the exposed shredded soil cores following irrigation and/or rainfall. Consistently improved water infiltration rates were recorded following cultivation on the sand root zone plots. In general only slight increases in the bulk density occurred below the tine penetration depth after 7 monthly cultivations (Table 3). The duration of the loosening action in the 2.5 to 7.6 cm zone derived from cultivation was relatively short-lived following annual aerification (Table 4-6) on the well structured Ragsdale soil. The amount of rainfall following aerification was an important factor on the longevity of the soil loosening action derived from aerification in the 2.5 to 7.6 cm depth. SUMMARY Aerification under sod can and does destroy the soil structure in the zone of cultivation thus temporarily counterbalancing the physical benefits derived from a vigorous rooting system and earthworm activity. This questions the desirability of annual or monthly aerification on well structured soils under turf that do not have an excessive organic layer accumulation. 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D. Comes2 When your program chairman asked me to visit with you today about aquatic weed control, I was hesitant because there have been no major changes in this area since I spoke to you in 1971. The major changes that I have observed over the past 7 years are the proliteration of aquatic plant growth, especially submersed species, and the public's awareness of the problems associated with such growth. I do not intend to infer that all aquatic plants or densities of aquatic plants are a nuisance. These plants play a vital role in the development and maintenance of a balanced aquatic community. Planktonic algae play an especially important role in the conversion of mineral nutrients, carbon dioxide, and light energy into organic matter which provides energy for other aquatic organisms. Vascular or higher aquatic plants provide food and/or shelter for aquatic insects, zooplankton, ducks, geese, and other aquatic life. In many cases, a few cattail, - To be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, WA, September 25-28, 1978. This paper reports the results of research only. Mention of a pesticide in this paper does not constitute a recommendation by the USDA nor does it imply registration under FIFRA. 2/ Research Plant Physiologist, Federal Research, Science and Education Administration, U.S. Dept. of Agriculture, Prosser, WA. bul1 rush or other emergent species provide a pleasing appearance to a pond or lake. Therefore, attempts to control aquatic plants should be limited to nuisance areas; they should not be eliminated from every body of water, even if this were possible. I have used the word "nuisance" to broadly define situations in which it might be desirable to control aquatic plants. What does nuisance mean? According to Webster, a "nuisance is a highly obnoxious or annoying thing or person; something offensive or annoying to individuals or the community." Because water has so many uses, and people differ in their opinion as to what constitutes an annoyance, designation of an area or species to be controlled is frequently more difficult than the control process itself. Most of you own or manage ponds or lakes in their entirety, so designation of areas where plants are to be controlled may not be a problem for you. However, on larger bodies of water that have multiple uses it is a major concern. After determining that aquatic plants are causing a problem and that control measures are desirable, considerable planning is required in selecting the most suitable approach. Some of the questions that must be asked are: Which species are causing concern? Which species are a part of the plant community that is not causing a problem? What are the growth habits and modes of reproduction of the various species present? What is the temperature, turbidity and hardness of the water? What fish species are present in the impoundment? What are the uses of the water in the impoundment? If the impoundment has an outflow, where does the outflow go, and what are the uses of this water? Can the water be quarantined from various uses and, if so, for how long? Other questions may need to be answered, depending on the individual situation. However, I feel that these questions must be addressed for nearly all areas where aquatic plant control is considered. Usually after these questions are answered, the method of control that can be used safely will be dictated by the circumstances. In discussing control methods, I will limit my remarks to ponds and lakes because I believe this is your sole area of interest. Principal methods of controlling unwanted aquatic vegetation can be placed into four broad categories - mechanical, environmental, chemical, and biological. The development of mechanical devices to mow and/or harvest aquatic vegetation has accelerated considerably during the past few years. Various underwater weed mowers or harvestors are available for mowing vegetation at depths of 6 inches to 6 feet beneath the water surface. Such equipment is available in a variety of models that range from portable units that can be mounted on a small pontoon boat to large and self-propelled units. Some manufacturers have developed complete systems of handling aquatic plants that include harvestors, transports, and shore conveyors. Advantages of mechanical control methods are that they present no direct hazard to fish, humans, livestock or wildlife. A few small fish may be trapped in dense plant growth and become removed with the severed plants, but this is not a major problem. Most, if not all, of the mechanical devices that I am aware of are not suited for use in the small ponds associated with golf courses and small parks. The time and cost required to get the equipment into and back out of small ponds, and to collect and remove the severed growth to a disposal site is high in relation to the area mowed. Another disadvantage of mechanical control is that many plant fragments are generated. Fragments of some submersed aquatic plants will form new roots and develop into individual plants. These plants may drift about the impoundment, sink and develop new colonies, or be transported in the outflow to various locations downstream where they may root and grow. Environmental controls are most easily and economically applied during the construction phase of pond development. Deepening the edges so that no water is less than 2 or 3 feet deep and complete removal of topsoil and organic matter from the basin render the basin inhospitable to many aquatic plants Installation of a bypass system to prevent drainage water high in organic matter or sediment from entering the basin may also reduce the rate of invasion and/or growth of aquatic plants. Another advantage of a bypass system is that water may be isolated in a pond should treatment with herbicides be necessary in future years. In many situations, a periodic drawdown of 5 feet or more reduces the incidence of rooted aquatic plants. Plants are exposed to desiccation during the summer, whereas they are exposed to freezing in the winter during the drawdown cycle. Chemicals have been used to control aquatic plants for the past 75 years, but it was not until the late 1940's or early 1950 1 s that there was a choice of more than one or two products. Several herbicides were registered for the control of submersed species between 1950 and 1963, but to my knowledge only one has been registered since 1963. Simazine (2-ch1oro-4,6-bis(ethylamino-s-triazine) was registered for the control of algae in 1976, and several submersed and floating species were added to the label early this year. Various formulations or chelates of certain herbicides previously registered for aquatic use have reached the marketplace during the past 15 years. I have not considered these to be new herbicides. There are two herbicides now under testing that I consider to have potential utility and sufficient interest by the manufacturers to develop. These herbicides are glyphosate (N_-(phosphomomethyl) glycine), and fluridone (1-methyl-3-phenyl-5-(3(trifluoromethyl)phenyl)-4(lHj-pyridinone). Glyphosate is effective on many emergent species and has been under public and private testing since about 1971. Fluridone is effective on a number of submersed and emergent species and has been under test in aquatic environments for 2 or 3 years. Neither is registered for use in the aquatic environment at this time. Thus, it appears probable that not more than one or two herbicides may be registered for aquatic uses in the next decade. This is a very optimistic view based on the past 15 years. Herbicides currently registered for use in various aquatic situations in lakes, ponds, and/or marshes include copper sulfate and a number of copper chelates, diquat (6,7-dihydrodipyrido(l,2-a:2", 1"c)pyrazinediium ion), three salts of endothall (7-oxabicyclo(2.2.1)heptane-2,3-dicarboxylic acid), the butoxyethanol ester of 2,4-D (2,4-dichlorophenoxy)acetic acid), dichlobenil (2,6-dichlorobenzonitrile), simazine, dalapon (2,2-dichloropropionic acid) and amitrole (3-amino-s^-triazole). Other herbicides are registered for use in aquatic sites in certain states, but they cannot be used in our region. Restrictions on the uses that may be made of the water after treatment vary widely for the various herbicides. In general, restrictions on the use of treated water for irrigation are the most severe. Thus, it is imperative to read and understand the label of each prospective herbicide before making a decision to use a chemical method of control. Most of the herbicides registered for the control of submersed plants in ponds and lakes are not toxic to fish at concentrations needed for vegetation control. However, when submersed or floating aquatic plants are destroyed by herbicides, they fall to the bottom of the impoundment and decay. The decaying process requires oxygen dissolved in the water. If a large portion of a moderate to heavily infested lake is treated at one time, the dissolved oxygen will be depleted below the level needed for the suryi\£l of a fish. No more than one-third of a heavily infested impoundment should be treated at a time. Ten to 14 days should elapse between successive treatments within a given impoundment. Control of aquatic vegetation with other living organisms is considered to be the ultimate and most environmentally acceptable method of control. Several scientists with federal and state agencies are very active in seeking and developing biological agents for several aquatic plants. Much of this work is aimed at the control of certain introduced weed species common in the southeastern part of the country. Herbivorous fish, insects, and plant pathogens are the principal organisms being studied. An herbivorous fish, the white amur ( C t m o pkcuiyngodon ¿deZtuu*) consumes large quantities of aquatic vegetation and could survive in many of the impounded waters of the Pacific Northwest. However, the effects that the white amur would have on native fish and on the total aquatic ecosystem are not fully understood. For these, and perhaps other reasons, the white amur has been outlawed in many states, including those in the Pacific Northwest. To my knowledge, the only biological control agent presently being evaluated, that may have utility in our region, is dwarf spikerush (E£eockcvuA coloiadozviAiA). This plant attains a height of only a few inches and grows in dense beds in some lakes and canals. In certain sections of some canals in California it has replaced pondweed species. Federal research personnel at Davis, California are continuing their studies on seed production, seed germination, seedling establishment, and the effects of soil and water parameters on the growth and survival of dwarf spikerush. Until these parameters are understood more fully, dwarf spikerush cannot be recommended as a method for the control of aquatic vegetation. Thus, we in the Pacific Northwest do not have any biological control agents to aid in reducing populations of troublesome aquatic plants. Many of you have probably read about the infestations of Eurasian watermilfoil (MyHsLopkytlum ¿p&doutum var. ¿ptcoutum) in Union Bay and in the Okanogan Valley of British Columbia. This is a very agressive submersed aquatic plant that apparently was unknown in Washington and British Columbia until about 1971. Eurasian watermilfoil forms dense mats of vegetation at the water surface and displaces most of the native submersed vegetation in waters of impoundments that are less than 18 to 20 feet deep. The plant will grow in relatively pure water with few dissolved salts as well as in water containing up to 10,000 parts per million salts (1/3 strength sea water). It grows on nearly all types of substrates and therefore has the potential of infesting many of our lakes, ponds, reservoirs, and river systems. Last year it was discovered in Banks, Evergreen, Billy Clapp, and Scootney Reservoirs in the Columbia Basin. I understand that Eurasian watermilfoil caused the State Parks Commission to designate a different area for swimming at Banks Lake State Park this summer. They were concerned that someone would get tangled in the Eurasian watermilfoil growth and drown at the former swimming area. Reproduction of Eurasian watermilfoil is primarily through plant fragmentation. Apical portions of the plant detach from the mother plant, float on the water surface, and eventually sink to establish new colonies. Rootlets are formed at the nodes along the stem of the mother plant at certain seasons of the year, and at other seasons the fragments form rootlets while floating. Propellers of motor boats drastically increase the rate of fragmentation. These fragments may be moved to other bodies of water through stream flow, plant parts clinging to motor boats or boat trailers, and on the plumage of waterfowl. The Tennessee Valley Authority has spent millions of dollars for the control of Eurasian watermilfoil over the past 10 or 12 years, and the British Columbia government had about 200 people working on various aspects of this problem in the Okanogan Basin this past summer. I believe these two examples demonstrate the potential danger of Eurasian water- milfoil to our water resources. Hydrilla [Hyd^uZla veMlciWLaXji), another submersed aquatic plant that we do not have in Washington, has the potential to become more troublesome than any species we now have. Hydrilla was first noted in this country in about 1960 near Miami, Florida. It is now present in several states, including Florida, Georgia, Alabama, Mississippi, Louisiana, Texas, Iowa, and California. Last year approximately $8,000,000 were spent for the control of this species in Florida alone. Hydrilla has the gross outward appearance of El odea (EJLoddci canad&yiAdA), a submersed species found in many of our waters. Hydrilla can be distinguished from El odea by its serrated leaf margins with pointed spines and spines along the midrib on the underside of the leaf. Hydrilla has four means of vegetative reproduction - fragments of foliage, rhizomes, turions, and subterranean tubers. It also flowers, but only pistillate or female plants have been reported in the United States. The efficiency of these reproductive structures was exhibited in Orange Lake, Florida where 12,000 acres were completely infested within 4 years. I urge each of you to watch for and report the location of plants which you believe to be Eurasian watermilfoil or Hydrilla to your local County Extension Agent. The old adage "An ounce of prevention is worth a pound of cure" surely applies to introduced aquatic plants. INNOVATIVE EQUIPMENT 1 By Larry Gilhuly 2 Before I begin I would like to thank the committee for the opportunity of speaking before such an esteemed group. In 1975 I graduated from Washington State with a degree in Agronomy. At that time I felt that practical experience was fine but that a college education was really the way in which to learn the processes involved in maintaining quality turf. While I still feel college does provide an excellent doorway to knowledge in our field, I now realize that it is practical experience which is the key to our business. With this in mind I would like to thank those superintendents who have had the guts and foresight to hire college graduates so that they may also gain a valuable education in furthering their knowledge of turfgrass maintenance. Today I will be speaking about innovative equipment. Before anyone can consider modifying a piece of equipment or constructing a new one from scratch, he must first ask himself, "Will the modified results warrant the cost of labor while keeping within safety standards?" If so, get started and have a good time. If not (see slide). — To be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, WA, September 25-28, 1978. 2/ — Assistant Superintendent, Seattle Golf Club, Seattle, WA. Thanks to the following superintendents for their cooperation in making this presentation possible. Seattle Golf Club Broadmoor Golf Club Overlake Country Club Tumwater Valley Inglewood Country Club Wayne U.S.G.A. Milt Bauman John Monson Sam Zook Doug Weddle Chuck Nolan Art Kain Bill Bengeyfield If you have further questions or interests any of the equipment shown, feel free to contact the superintendent. MAINTENANCE PHILOSOPHIES' EFFECT 1 ON BUDGETS By Bob Wick2 Rather than discussing golf course budgets in the terms of dollars and cents, it would be far more profitable and more fair for us to look at the contrasting factors at different courses which dictate where the dollars go. I'd like to break these factors into two groups, physical factors and club philosophies, and take a look at a few items which cause differences in maintenance budgets. Some items could be in both categories, as you will see, but most are distinctly separated. This is not a guessing game as to where the slides were taken or which course does what procedures, but rather an objective view of the subject. Please do not try to figure out where the slides were taken or you'll prejudice your objective thinking. Remember, we are talking about tracts of property under various ownerships, used to play the game of golf. Therefore, there is no set standard of maintenance other than the owner's wishes and the observation of the rules of golf. — To be presented at the 32nd Annual Northwest Turfgrass Association Conference, Holiday Inn, Richland, WA, September 25-28, 1978. 2/ — Superintendent, Capilano Golf Club, W. Vancouver, BC, CANADA. What are some physical factors over which a golf course superintendent has little or no control that affect the maintenance budget? A few are: - number of acres maintained; number of traps and their size; size of greens and tees; source of irrigation water; amount of area requiring special maintenance; number of deciduous trees; vandalism; etc. The contrasts of the physical factors are quite straightforward if one assesses them honestly. But the contrasts caused by a club's philosophy can be somewhat more subjective. At this point I want to reiterate that there is no practice which is necessarily a "better maintenance" than another. Often economy is an influencing factor on a maintenance procedure, but that does not mean that more money makes a better finished product, but rather to meet the specific desires of a membership more or less money is required in certain areas. A golf club must assess its own goals within the means of its budget, and be satisfied having achieved its goals, regardless of any other golf course. Comparing North American golf courses to many of the current and original great golf courses in Scotland, where the game began, we are over maintaining by a large percent. The game of golf is played in both places and enjoyed equally. Therefore, we may conclude there is no norm or standard that needs to be met other than the owner's wishes. Having interrupted with that parenthetical thought, let's move on to the maintenance procedures that are affected by the philosophy of the golf club. Some of these areas of maintenance are: - greens : frequency of mowing, method of mowing, height of cut, collars; - tees: frequency of mowing, method of mowing, height of cut, area around tees; - fairways: fertilizer program, frequency of mowing, height of cut, irrigation practices; - roughs: no roughs, natural roughs, two-step roughs, height of cut; - sand traps: number, method of raking, frequency of raking, type of edge; - cart paths: natural or vegetation free; - entry to club and clubhouse area; - disease control other than greens; - triming around trees: hand rotary, chemical control ; - lakes: natural growth, vegetation free, shores; - weeds. A goal of a profit-making golf course is to make money which is done by taking in more than it spends. Theoretically, only enough maintenance has to be done to keep the money coming into the till. If not enough money is coming in then changes must be made to entice the golfer. It's just pure merchandising like any company selling a product. Sounds simple, doesn't it? Or is it? Unfair comparisons are made which compare golf courses that have different sets of goals to meet. The goal of many clubs is to provide service to their members and to not make a profit. The amount of service, the aesthetics and the philosophies required by the membership dictate the amount necessary in the budget. The golf course has been terribly North Americanized to the point where people forget it is for the game of golf which is supposed to be a challenging sport. This is where the unfortunate dilemma appears. A golfer says he wants a challenge but at the same time he complains when he is met with a challenge. The game is played in every instance and the important consideration is whether the golfer is happy when he or she drives out of the parking lot. Just as beauty is in the eyes of the beholder, so is there satisfaction in the achievement of a club's individual goals, provided they are specifically defined. With an honest approach, both the golfer and the management of the golf course can be satisfied. THIRD INTERNATIONAL TURFGRASS CONFERENCE MUNICH, WEST GERMANY, JULY 11-13, 19771 D. K. Taylor 2 Last July it was my privilege to attend the Third International Turfgrass Conference held in Munich, West Germany. There were 240 delegates attending from some 19 countries, coming from as far as Australia and Japan. Professor Peter Boeker of the Institute of Agronomy at Bonn was the Chairman, host and chief interpreter during the tours in connection with the Conference. The aim of the International Turfgrass Society in sponsoring the Conference was to improve communication among turf researchers by exchanging information on techniques and procedures on how to improve turfgrass production. A total of 91 papers were presented in 13 sessions over a three-day period, each dealing with a particular topic. Communication at the Conference was facilitated by simultaneous translation in 3 languages, German, French and English, the cost of which was borne by the Bavarian and West German Departments of Agriculture. At the business session, the Society voted to hold the next Conference in Canada in 1981 and Dr. Clay Switzer was elected president. Presumably the Conference will be held at Guelph and the International Committee of nine is already making plans for — To be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, WA, September 25-28, 1978. 2/ — Head, Crop Science Dept., Agriculture Canada, Agassiz, BC, CANADA. that event. My attendance at Munich was a great educational experience and it was a distinct pleasure to travel with other turfgrass scientists and learn that Europe and North America have many turfgrass problems in common. Rather than reviewing the papers presented at the Munich Conference itself, I would prefer at this time with the aid of slides, to give you a few of my impressions of the turfgrass production and research shown to us throughout West Germany, Switzerland and France during the Conference tours. In West Germany, for example, their biggest turfgrass concern is having good grass in their many stadiums, since soccer is of prime interest. Much research is going into soils and media on which to grow sportsturf. Perennial ryegrass is by far the most popular grass for this type of seeding, and just as Manhattan has become a standard of excellence in North America, Loretta is receiving similar attention in Europe. There is also a growing awareness of the usefulness of Kentucky bluegrass and the limitations of fescue, timothy and crested dogstail for sportsfields. Most researchers were applying a simulated wear treatment not only to their variety trials but also their management studies. Active plant breeding programs were observed in both West Germany and France. Roadside seeding research programs were active in all three countries visited. At least two major commercial firms were promoting the idea of renovation of home lawns and actively promoted the use of specialized equipment and products to do the job. Everywhere we went we sensed a developing interest in turfgrass. The Cologne-Mungersdorf stadium built in 1975 is a very modern facility which includes a synthetic running track surrounding the soccer pitch. The soil for the soccer pitch was modified to 85% sand but the initial seeding was a failure. The turfgrass sod, procured from a heavy soil site near Bremen, also gave problems in management. However, following frequent coring together with sand topdressing and overseeding with perennial ryegrass, a respectable playing surface has resulted. West German researchers such as Professor P. Boeker at the Institute in Bonn and Dr. Skirde at the University of Giessen are investigating the usefulness of synthetics, plastic foam, hygromull and flygropor to improve the aeration and drainage of heavy soils. In France specialized equipment has been developed for opening up slit trenches and automatically filling these with granular synthetic materials. Dr. Skirde had an impressive series of experiments to investigate the effectiveness of various drainage layers, modified subsoils and rootzones. Dr. Skirde also showed us the results of some of his roadside seeding experiments. Chewings fescue did well on south slopes while creeping red fescue was more adapted to north slopes. Other species which were promising included Kentucky bluegrass, colonial bentgrass, birdsfoot trefoil and lupins. His studies of salt tolerance indicated the superiority of Dawson fescue. Less tolerant but best of their respective species were Skofti Kentucky bluegrass and Penncross bentgrass. At Betsdorf, we visited the Wolf-Gerate trial grounds and were given a tour by Dr. Pietche. This company is associated with 0. M. Scott and has operations in West Germany, Netherlands, Luxembourg, Belgium, Switzerland, Italy and Scandinavia. Excellent variety trials were observed along with various renovation and management trials. Poa ¿up¿nla, a relative of Poa annua, was among those entries under trial. P. ¿uplna, originating at high altitudes, is an attractive dense low growing grass which is early green, "winter" green, resistant to disease, and produces roots and shoots at the nodes. Owing to its short culm height, commercial seed production would be difficult with this grass. The BASF research facility at Limbergerhof was most impressive. This company spends $300 million annually in agriculture research in several countries developing such products as slow release fertilizers, pesticides and growth retardants. One-half its sales are of products developed within the last 10 years. This company rolled out a green carpet to welcome the group. It consisted of grass growing on one of their synthetic granular products. At Steinach in Bavaria we visited an old seed firm originated by Dr. M. von Schmieder. At one stage it was a grass breeding school. Mr. Frank, now retired, was responsible for selecting and increasing the variety Loretta, one of the most promising ryegrasses observed in European trials. Close by at Strasskirchen we observed a new sportsfield featuring a seedbed modified with 40% sand, 10% peat, 10% hygropor, and a 2 cm topdressing of sand applied prior to seeding. The seeded mixture containing Loretta perennial ryegrass and Parade and Enmundi Kentucky bluegrasses showed excellent vigor. A visit to Eder Am Holz featured the Federal Cultivar Testing program. This is one of five locations in West Germany and the Netherlands where varieties of cereals, forage (turfgrass), potatoes and fiber are grown for descriptive purposes. Each new variety must be uniform, stable and distinctly different from those already described, to qualify for registration under a system which takes into consideration Plant Breeders Rights. In addition a cultivar testing program featured seedings in two successive years at 5 locations with regular observations and wear treatments. The Olympic stadium in Munich is an impressive sports complex covering 45 hectares in area. Although the main stadium receives intensive management, the many practice fields are less intensively managed under contract. The surface layer (10 cm) of the main stadium was constructed out of 60% sand (0-3 mm) and 40% decomposed peat. The nature and high content of peat proved to be a problem in spite of good drainage layers below. Heating pipes were also installed at intervals of 40 cm. The original seed mixture was composed of 70% Merion, 15% S50 timothy, and 15% crested dogstail. In 1977 a botanical count indicated a cover of only 9-13% Kentucky bluegrass, 1-2% timothy, no crested dogstail, 66-43% Voa annua, 1-26% Voa i/Uv¿aLU and 2316% perennial ryegrass. The range in percentage indicates areas of heavy and light wear respectively. Annually since 1974 the stadium has been overseeded with perennial ryegrass along with an aerifying and topdressing program. Three golf courses were visited in Switzerland ranging from a hillside improved natural pasture course located near Gstaad to a well seasoned 53 year old course at Lausanne, to a modern Trent Jones designed course built in 1972 at Geneva. The Gstaad course is only open from June 15 to October 30 and is located at 5000 ft elevation. Fairway roughs featured an unique array of flowering plants at the time of our visit. At Lausanne the fairways were also improved natural pasture while the greens were seeded in the post war period to New Zealand browntop. One exception was the 15th Green which featured a 1935 seeding of German bent, obtained from indigenous bentgrasses which produced seed crops following logging operations in the Black Forest. Many of our modern bentgrass varieties trace their origin to bentgrass seed gathered in this manner. The course at Geneva was comparable in appearance and maintenance procedures to a top North American course. Tees, fairways and greens were all seeded to Penncross bentgrass. The greens observed were P. annua-free but appeared to be on the verge of having a thatch problem. The magnificent club house overlooked a double green for the 9th and 18th holes which measured 1800 square meters in size. Beyond the green Mt. Blanc could be seen in the distance. Edgar Schweizer of the Eric Schweizer Seed Company was our tour host in Switzerland. This company has trial grounds for testing varieties, mixtures, herbicides and renovation procedures, and considerable experience in roadside seedings. Ten years ago it was a common practice to insist on top soil for roadside seedings, now with the use of slow release fertilizers and straw mulch good stands have been obtained. Recommended mixtures contain a variety of fescues, perennial ryegrass, mildew resistant Kentucky bluegrasses, colonial bentgrass, red clover, trefoil and shrubs on slopes over 15°. Our first stop in France was at Lusignan, an INRA station supported by the Federal Government. Under the direction of Paul Mansat this station has an active grass breeding program with an interest in ecological adaptation; resistance to wear, herbicides and disease; as well as color, density and yeararound appearance. For drought resistance they have found the fescues to survive short duration droughts well but after a long drought perennial ryegrass recovers faster with little killing. Waldorf fescue was superior for its wear tolerance. Vilmorin-Andrieux is one of the long established seed companies of France which sends its seeds to some 90 countries. In 1728 Vilmorin had a retail seed outlet in Paris which has continued in business to this day. Their breeding program at La Menitre is actively producing new varieties of vegetables, flowers and turfgrasses. Their new perennial ryegrasses are particularly attractive and could be of interest to the Pacific Northwest since the most attractive varieties of turfgrass at Agassiz are those which perform well at this location in France. One of the interesting stops in Paris was at La Defense, an older area of the city, which has under construction a 150 ha complex of business and commercial enterprises. In order to alleviate the mass of concrete, plane trees have been planted in concrete tubs, ground cover and shrubs in smaller containers and turfgrass in a Purr-wick type of installation. Fortunately they have research trials under way to investigate watering systems, rooting media, species and varietal adaptation. The Chantilly Race Track featured another aspect of turfgrass maintenance. This complex has 100 km of sand tracks, 124 ha of turfgrass and facilities for training 3500 horses. The soils for grassed tracks have been modified with 75-95% sand. The aim is to have well rooted turf with some cushion effect. The latest seeding mixture includes 25% perennial ryegrass, 35% creeping red fescue and 40% Kentucky bluegrass. Each year a mixture of perennial ryegrass varieties is used to overseed the grassed areas. Divotting by horses is more extensive than by golfers and these marks are repaired by workers using hand tools followed by treading or rolling. These are a few of the many experiences of which I had the privilege of sharing with my fellow turfgrass researchers. Papers from the Munich Conference itself will be published this year by the American Society of Agronomy. To have attended the III International Turfgrass Conference and its tours was an exciting educational experience for me and a chance for all those interested in turfgrass to communicate more effectively with one another. MICRONUTRIENTS IN TURFGRASS MANAGEMENT 1 Paul E. Rieke2 There are 16 different elements usually considered essential for turfgrass growth. Carbon (C), hydrogen (H), and oxygen (0) are provided mostly from water and gaseous forms. Nitrogen (N), phosphorus (P), and potassium (K) are the important primary fertilizer nutrients. Calcium (Ca), magnesium (Mg), and sulfur (S) complete the list of macronutrients or those nutrients needed in larger quantities by plants. The micronutrients are those nutrients required in small quantities by the plant. But it is just as important that they be present in adequate concentrations in the plant. These include iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), boron (B), molybdenum (Mo), and chlorine (CI). Occasionally, sodium (Na), silicon (Si), and a few others are suggested as providing some benefit for plants, but data are not available to prove their essentiality for turf. Micronutrients are also called minor elements, minor nutrients, microelements. Concentrations of macronutrients we have found in Kentucky bluegrass clippings given as averages over the growing season are 4.2%N, 0.4%P, 2.5%K, 0.4%Ca, and 0.2%Mg. Concentrations of micronutrients found were 280 ppm Fe, 41ppm Mn, 40ppm Zrj, 17ppm Cu and 9ppm B. The micronutrient concentrations are usually listed in ppm (parts per million) because of — To be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, WA, September 25-28, 1978. 2/ — Dept. of Crop and Soil Sciences, Michigan State University, East Lansing, MI. their very low percentages present. By contrast, the 4.2%N is the same as 42,000 ppm N compared to the 280ppm Fe, etc. Although concentrations of micronutrients are considerably lower than for the macronutrients, their presence in adequate quantities are equally essential. Careful attention should be given to management of the micronutrients when it is known they are needed for the turf. Evaluation of micronutrient needs for turf presents some unique challenges. A complicating factor is that some nutrients, like iron, are present in soils in relatively high quantities but are in a form that is unavailable to plants. Applying iron in a form like ferrous sulfate may result in rapid fixation in a form that is unavailable. Effective soil testing should be able to test the form available to the plant but should not extract the unavailable forms. Deficiencies of micronutrients are more difficult to diagnose with soil tests than for macronutrients since there has been little soil test correlation research for micronutrients on turf. Clipping analyses are not especially useful because of variation of nutrient concentration through the season and because of soil contamination of the clippings. Most visual nutrient deficiency symptoms are associated with a yellowing (chlorosis or loss of chlorophyll) of the leaf tissue making it difficult to differentiate among the nutrient deficiency symptoms or from other causes associated with yellowing of the turf. The micronutrient most often limiting in turf is iron (Fe). When iron is limiting it can often be associated with one of the following conditions: high pH soil; high soil levels of phosphorus; manganese or zinc; high soil organic matter levels; clipping removal; compacted soil conditions; waterlogged soils; a heavy thatch condition; and short roots. Since iron is quite insoluble in water and readily converts to unavailable forms when applied to the soil, any condition which results in short root systems will increase the probability of iron deficiency: nematodes, short mowing, high temperature (on cool season grasses), high nitrogen fertility, or disease, insect, soluble salts, or chemical injury. Deficiencies of other micronutrients in turf have not often been reported. Since manganese, copper and zinc react somewhat similarly to iron in the soil, deficiencies of these nutrients might be predicted under the same conditions for which iron might be deficient. Based on experiences with other crops one might predict that manganese responses on turf would become more common in the future. Iron can be applied to turf as a foliar application of ferrous sulfate, ferrous ammonium sulfate, iron chelates, or other soluble iron sources. Ferrous sulfate is most frequently used and is applied as a foliar application. This is usually applied foliarly at the rate of 1.5 to 3 oz of ferrous sulfate in 3 to 5 gal of water per 1000 f t 2 . When applied to actively growing bentgrass on our research plots the improved color of the turf lasted from 3 to 8 days depending on how rapidly the turf was growing. Rates as high as 12 oz/1000 ft 2 were applied every two weeks on a research green and improved the green color, but there was some injury to the turf especially at the 12 oz rate. This resulted in browning of older leaves and some thinning of the turf. Manganese, copper and zinc can also be applied in the sulfate form. If the need for these nutrients is suspected one could use foliar applications at somewhat lower rates than for ferrous sulfate. Be careful to apply these when the turf is not in a temperature or moisture stress condition for they can cause injury. Certain sewage sludges contain appreciable iron. The iron in Milorganite is one of the factors in turf response to applications of that fertilizer. Zinc and other micronutrients may also be high in some of the sewage sludges. Some fertilizer companies include iron and other micronutrients in their fertilizers for convenience of the turf manager Iron, manganese, copper and zinc can all be applied as chelates. Since the chelates vary widely, follow the manufacturer 1 s directions. Success with chelated forms has been varied. Some materials have given good results while others have been ineffective Some work only when applied to the foliage. Others, reportedly keep the micronutrient available to the plant when applied to the soil. If the micronutrients are mixed in with a complete fertilizer there may be certain percentages which must be guaranteed according to state law. This varies by state, but the concentrations should be such that when the complete fertilizer has been applied at the rate appropriate for nitrogen then the micronutrients will be applied at an appropriate rate. If there is need for boron or molybdenum on turf these can be applied as borax or sodium molybdate, respectively. The sodium molybdate need would be at very low rates. Borax, if needed, should be applied very carefully. Borax can cause injury to turf at very low rates. The use of "shotgun" applications of micronutrients has been suggested as a means of being sure that there is not a deficiency of micronutrients. The concern with this approach is that even as only a small amount of these nutrients is needed by the plant, only a small excess could potentially develop and result in a toxicity. It might be wise to treat a smaller area experimentally with micronutrients before treating your entire turf area. Better yet, apply specific nutrients in different places. Then you will be better able to determine which nutrient is giving the response if one occurs. If you get a response to the "shotgun" mixture there is no way to be sure which nutrient is causing the response. Even as you would not correct a shortage of phosphorus by applying potassium, by the same token you would not apply zinc to correct a manganese deficiency. In fact, it is possible to induce a deficiency of a micronutrient which was not previously a problem by applying an excess of another. So micronutrients should be used wisely in good turf management. PURR-WICK AND P.A.T. SYSTEMS IN TURFGRASS MANAGEMENT 1 John M. Roberts2 THE PURR-WICK SYSTEM A large majority of the turfgrass under cultivation in the world is on naturally occurring physically unamended soils. Due to the intense traffic that putting greens undergo, most natural soils do not have the physical properties necessary to maintain a stable root zone with time to meet the turf quality requirements golfers desire. Under natural soils having inherent structural instability compacted soil surfaces, impaired drainage and root growth occur resulting in weakened turf more susceptible to environmental and stress factors. Recent management practices have favored the use of sand alone or in combination with natural soils for the root zone medium to minimize soil compaction in turf areas subject to heavy traffic. One of the main advantages of pure sand is its structural stability which once settled, provides ample pore space for water and air movement into the root zone thus maintaining a uniform and well drained playing surface. This is essential, for good surface drainage is a key factor for maintaining a uniform turf stand on heavily used areas. A need to increase water retention in sand is required due to the relatively low water retention — To be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, WA, September 25-28, 1978. 2/ — Turfgrass Research Associate, Western Washington Research and Extension Center (WSU), Puyallup, WA. capacity. The most effective way of conserving moisture in pure sand is to underlay the root zone with an impermeable barrier, such as plastic sheeting. This provides a potential saturated reservoir zone thus allowing water to move upward to the plant roots by capillary action. Plastic lined sand root zones are referred to as Purr-wick root zones (plastic under reservoir root zone) which utilizes the principle of wick (capillary) action. The essential features of Purrwicks are the pure sand rooting medium which utilizes the large pores of compacted sand above an impermeable plastic barrier, accompanied by drain tubes and adjustable outlets which can remove, conserve or redistribute water as needed. Due to the slope desired in putting greens internal dividers up to 30 cm high are installed at every 20 cm change in contour to maintain a more uniform water reservoir level throughout the putting green. However, field reports from turf managers of Purr-wick putting greens have cited that imbalance in the water reservoir has developed with the majority of the reservoir concentrating in the lowest compartment of the putting green. Most of the water movement over the internal divider has been observed following heavy rainfall when the sand was under low soil moisture tension. One design modification under consideration in construction of future Purr-wick putting greens is to increase the height of the internal dividers in hopes of retaining a larger water reservoir especially in the upper compartment. The main objective of this investigation was to study the rate and amount of water movement in sand medium separated partially by internal dividers of varying height. The sand used in both the laboratory and field studies consisted of 50% fine and 50% medium textured sand. As shown in Figure 1, the reservoir levels were depleted in a short time period using internal dividers 20 or 40 cm high. After 3 hours following saturation to the top of the 20 cm internal dividers under laboratory conditions, the reservoir had been completely exhausted. After 24 hours following saturation to the top of the 40 cm internal divider, 95% of the reservoir had been depleted. The rate of water movement over the internal divider was markedly reduced with only slight moisture reductions from saturation. For example, the hydraulic conductivity decreased 90 to 95% as the percent of saturation in the Michigan dune sand was reduced from 100 to 75%. The data in Figure 1 indicate that rapid reservoir depletion rates in the upper compartment in Purr-wick putting greens are to be expected even if the internal divider heights are increased to within 6 cm from the surface. This is providing that there is no assistance from the rooting system. The question remains unanswered, what influence the rooting system has on retarding water movement over the internal dividers. It is believed the net result of using higher (40 cm) as compared to lower (20 cm) internal dividers in the upper compartments is that (i) a greater quantity of water will move nearer the surface where the majority of the roots are located, and (ii) there will be a faster reduction in the moisture content from saturation at the top of the internal divider thus reducing the rate of water movement over the internal dividers. As shown in Figure 2, water reservoir levels at different elevations will try to seek similar levels until a state of equilibrium exists even when separated partially by an internal divider. This information when applied to Purr-wick putting greens where sub-base slopes exist thus creating potentially large differences in the reservoir levels adjacent to the internal dividers indicates that only when the reservoir levels adjacent to the internal dividers are at similar elevations will the movement of water over the divider be minimized. Under field studies, the rate at which the water reservoir levels in the upper compartment (Figure 3) depleted was rapid especially at low soil moisture tension. With a sub-base slope of 7%, 69% of the reservoir was depleted within 24 hours following saturation to the top of the 30 cm internal divider. The soil moisture content at this time was 86% by volume of the saturated value as measured at the top of the internal divider. The rate of water movement over the internal divider had practically ceased 60 hours following saturation when the soil moisture content at the top of the internal divider was 66% by volume of the saturated value. The net result of this rapid water movement over the internal dividers was an imbalanced distribution of water throughout the putting green with the majority of water accumulating in the lowest compartment. For example, 24 hours following irrigation a 36 cm water reservoir accumulated in the lowest compartment whereas a 0 cm reservoir existed in the upper portion of the uppermost compartment. SUMMARY Excessive water movement over the internal dividers in the Purr-wick method of constructing putting greens was created by an imbalanced water reservoir level adjacent the internal divider and was accelerated at low soil moisture tensions. In order to retard this water movement design modifications of future Purr-wick putting greens believed to be beneficial include: (i) the elimination of sub-base slopes exceeding 3%, and (ii) the extension of the internal dividers to within 7 cm of the final surface. THE P.A.T. SYSTEM The P.A.T. system (Prescription Athletic Turf) is one method of constructing an athletic playfield. In 1970 Dr. Bill Daniel and Mel Robi of Purdue University were the co-inventors of the P.A.T. system with the first P.A.T. football field being completed in 1972 at Goshin High School, Indiana. The P.A.T. system includes (a) suction pumps, (b) collector drains, (c) sand, (d) plastic sheeting, (e) peat and vermiculite, (f) moisture sensors and controller, plus other potential additives such as soil heating cables and vented plastic covers and power rollers. When you put these features together, the athletic field can be a pleasure for both players and turf managers alike. Probably one of the main advantages of the P.A.T. system (by using an all-sand root zone with suction pumps connected to the numerous drain lines above the plastic lining) is the rapid removal of water from the playing surface even if it rains during the game. No longer does rain during the game mean muddy, slippery footing for the players. In 1976 there were 3 high schools, 3 pro (Washington Redskins, Miami Dolphins, Denver Broncos), and 5 University fields with suction pumping installed. As I was a graduate student for nearly 4 years under Dr. Daniel, I was able to hear and see how the various P.A.T. fields were responding under various play and management. In general, the system has been popular among both players and turf managers. I saw the Purdue football team (having the P.A.T. system) play under a heavy rainstorm yet maintain firm footing. The one aspect of this system that the turf managers have had a tendency to do is to overwater. It should be kept in mind the that plastic barrier prevents water loss from the root zone thus the need to water is reduced. What about the cost? In general, the P.A.T. system costs 1/3 that of artificial surfaces. It is my personal opinion and hope that the P.A.T. system will increase in popularity with time. INTERNAL DIVIDER HEIGHT CM 20 40 M O I S T U R E C O N T E N T , % OF 100 95 100 94 40 fi—r 93 91 90 85 87 70 SATURATION 60 80 45 25 T"T Divider Height, cm 30 J 20 -----40 20 r \ \ 10 // 0 .5 ih12 24 TIME, HOURS Figure 1 . T h e r e s e r v o i r d e p l e t i o n rate f o l l o w i n g s a t u r a t i o n using internal d i v i d e r heights of 20 and 40 err. 48 O > CD 10 CD L. CD TD C O E O O CD CM QL CD CD TD4->E CD U CD U. O > • —, "O CD CD M CD IN _ CD CD > CD JZ CVJ CD o m '13A37 HI0AH3S3H en cen 21-0-0>34-0-0, 38-0-0 complex> 38-0-0>46-0-0. Highest yields were obtained from 34-0-0>46-0-0>21-0-0>38-0-0. Late fall applications of nitrogen increased winter and spring greenness without increasing disease. FiMa/tium patch incidence increased with high nitrogen (15 lb), high lime (pH 7.0 plus) and the use of 46-0-0 as a source of nitrogen. P0A ANNUA CONTROL STUDIES Competitive differences with P. annua among three bentgrass varieties continue to be evident, Penncross>Seaside>Highland. All plots receiving regular applications of bensulide have less Poa annua than other treatments. Differences owing to high sulfur or low phosphorus were not evident in 1977. Four treatments using various rates and timing of endothall were applied. Rates of 0.75 lb ai/A were temporarily phytotoxic. The bentgrass recovered quickly, howe v e r , in mid-summer applications but too slowly from September applications. As much as 2.5 lb ai/A was applied to varieties of Kentucky bluegrass with a good reduction in P. annua. This rate was not effective on weedy creeping bentgrass. Linuron was also promising for use on Kentucky bluegrass at the higher recommended rate (0.1 lb ai/1000 f t 2 ) . Both products were completely phytotoxic to P . &Uvi,aLa>. A great variation was observed among Kentucky bluegrass varieties in their resistance to these herbicides. Fylking was most susceptible followed by Birka. Baron, Sydsport and Cheri were among the most resistant. Merion was average while Bristol was resistant to linuron but susceptible to endothall. RESULTS OF COMPETITION AMONG THE COMPONENTS OF FESCUE-KENTUCKY BLUEGRASS MIXTURES Variety is an important consideration in formulation mixtures of turfgrass species for home lawns. Some varieties such as Highlight may be so agressive that they crowd out competing Kentucky bluegrasses in simple mixtures. Seedings made in 1972 and 1973 of mixtures of high and low density fescues and Kentucky bluegrasses were studied in 1977 to see what the survival had een under 3 fertility levels (1, 3, 5 lb N/1000 f t 2 ) and 2 heights of cut (3/4 and 1-1/2"). A count of the number of tillers per unit area showed the following order of density among fescuesHighlight>Durlawn>Boreal, and Kentucky bluegrass Nugget>Merion>Sodco. All mixtures of Boreal fescue with varieties of Kentucky bluegrass gave close to a 1:1 tiller count whereas comparable Highlight mixtures were at best 9:1, fescue:bluegrass. At Kamloops the results were equally pronounced although bluegrasses, and Nugget in particular, were somewhat more competitive. In general, increases in fertility and lower cutting height increased the number of tillers, giving increased density. Increased fertility reduced tiller weight for fescue but not for Kentucky bluegrass. At Kami oops where Kentucky bluegrass is better adapted, tiller weight was 80% greater than at Agassiz, at the 3/4 inch cutting height. Higher density also resulted in higher thatch measurements. Therefore, in formulating simple mixtures of species for home lawns where survival of both components is important, it appears necessary to consider the competitive ability of the varieties used. Highlight, a very attractive Chewings fescue when grown alone, may be too competitive in mixtures with Kentucky bluegrass for survival of the bluegrass. Although the use of Boreal in mixtures gave a better survival of both species, perhaps a more disease resistant variety should be chosen such as Pennlawn. SNOW MOLD CONTROL IN THE B. C. INTERIOR Four years of trials in the B. C. Interior have shown the usefulness of Caloclor, chloroneb and quintozene for the control of snow mold on putting green turf caused by Typhoid spp. and FtiscvUum vuvcULd. All products were applied in one application prior to snow fall. Caloclor was highly effective at the 5 oz rate but showed slight temporary toxicity in the spring. The 3 oz rate was not completely effective in a one year trial. Of the non-mercurials chloroneb at 6 and 9 oz was most effective although quintozene at 8 oz gave almost as good results. Granular applications have given good basic disease control but were slightly less effective than spray applications. For example, in a one-year trial (1976-77) RP 26019 at 2 or 4 oz gave good disease control as a spray but 4 or 6 oz were required to be equally effective as a granular product. SLOW-RELEASE NITROGEN STUDIES — IDAHO 1 R. D. Ensign, V. C. Hickey, R. E. McDole 2 Several slow-release nitrogen fertilizers were evaluated in 1978. The purpose was to determine response to rate of N , rate-combination, time and form of the nitrogen materials upon the growth and quality of bentgrass in Idaho. These fertilizers were compared with a highly soluble ammonium nitrate formulation. The materials used are given in Table 1. The experiments were conducted on two distinctly different types of golf greens. The green at the University of Idaho Golf Course was constructed with 18 inches of sand and seeded to Seaside bentgrass in 1968. The green at the Moscow Elks Golf Course was an old putting green which was constructed from fine silt loam typical of the Moscow region. Highland bentgrass was planted on the green in 1946. It has a deep thatch-mat layer. The winter and spring of 1977-78 recorded above normal moisture levels, thus these greens were very low in available N at the time of the early spring N treatment. The results of the applications on color response of the bentgrass are summarized in Table 2. — To be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, W A , September 25-28, 1978. 2/ TABLE 1. Slow-release nitrogen fertilizer materials and ammonium nitrate Treatments Source of N Materials Rates and Dates* 1 Scotts 29-3-3 22.4% WS** Methylene Urea 5.8% WIN Methylene Urea 0.8% Ammonical N 2+2+2 2 Scotts 22-0-16 14.0% WS Methylene Urea 7.5% WIN Urea and M.V. 2+2+2 3 Nitroform-M 38-0-0 Organic Urea Formaldehyde (UF) 27.5% WIN UF 10.5% WS UF 2+2+2 4 IBDU 31-0-0 Isobutylidene Diurea 27.9% WIN 3.0% WS 2+2+2 5 IBDU 31-0-0 Same 3+3 6 IBDU 31-0-0 Same 4+4 7 Milorganite 6-2-0 Natural organic activated sludge 5.5% WIN 2+2+2 8 Ammonium Nitrate 34-0-0 Nitric N 17% Ammonic N 17% 2+2+2 * 2+2+2 = 2 lb N/1000 f t 2 April + 2 lb Mid-June + 2 lb September; 4+4 = 4 lb N/1000 f t 2 April + 4 lb September, etc. ** Note: WS = Water Soluble Nitrogen O L CO ** S- r __ ° L CD 00 CO LO LO scu JQ E CU +-> Q_ CU fO O E O O 00 CO CU 03 C D C CU rö OO S - c c>u » LO < CO 1 co i CT> CM -X CM + 4C-O> CM + 4O-> CM O OO c u s- 7LO O1 CM * CM +CM CO CM +-> + +O-> CM O OO o1 O 1 cñ E* S- CM O + 4— O +CM S- CM 4-> • r — z: oi O -X 1 CM ÍCO — CM 4+ IO CM O t—( CÛ o1 o 1 r — CO 4co =0 co O00 i 00 O1 o 1 r — CO 4^-íZD Q CO I—I CU CU CM 4J 4fO CM 4+L--> CM -l-> E • 1 — EO E O 3 1 f ÖCM1 • en r- O 1 S- 1 E o O LO r — E^ co O • r — s: e _Q CU CU LE ^ fO SCU n 3 s: Q * * * Summary and Conclusions 1. Both greens were very low (below 5 ppm NCU) in available N in April at the beginning of the experiment. 2. Four slow-release nitrogen fertilizers were evaluated for grass growth on two distinct kinds of greens in Moscow, Idaho. The fertilizers had different water-soluble (WS) components. (See Table 1) 3. The nitrogen was applied at a seasonal total of 6 lb of actual N/1000 f t 2 . Treatments were applied at 2 lb of actual N in early April, midJune, and mid-September. An additional treatment consisted of IBDU applied at 3 lb N in April plus 3 lb N in mid-September, another treatment consisted of IBDU at 4 lb of N in April plus 4 lb of N in September. No summer application was made for those two treatments. 4. Rapid green-up responses were noted with Scotts 29-3-3 and ammonium nitrate and to a lesser degree with Scotts 22-0-16, Nitroform-M and Milorganite. The IBDU carrier is thus 27.9% water insoluble (WIN) and only 3% water soluble N. Thus rapid green-up was not observed as with Scotts 29-3-3 and ammonium nitrate fertilizers. The plots in which IBDU was applied gradually improved as the summer progressed. It appears that several annual applications are needed for these slow-release materials to buildup adequate N for plant growth. 5. Some balance between WS and WIN forms of N seems to be a practical answer to proper grass nutrition and appearance. Such formulations may vary depending upon the season and other environmental conditions. EVALUATIONS OF TURFGRASSES UNDER IDAHO CONDITIONS 1 R. D. Ensign, W. R. Simpson and V. G. Hickey 2 Since 1972 numerous turfgrasses have been evaluated for adaptability and performance in two areas of Idaho. Evaluations were conducted on irrigated fine silt loam near Moscow, Idaho, where the climate is generally moist and cool in the late fall to early June. Mid-summer is usually semi-arid with relatively cool nights. The second location was in southwestern Idaho at the Parma Research and Extension Center. The irrigated soil is a deep Greenleaf fine silt loam relatively high in pH. The climate is arid and the summer temperatures which frequently exceed 95°F are generally higher than at Moscow. Summer stress on turfgrass is usually greatest in southwestern Idaho. Moscow Location During 1978 the following species were evaluated at Moscow: 63 13 18 1 11 3 2 1 112 Kentucky bluegrass cultivars Perennial ryegrass Fine-leaf fescue Tall fescue Bentgrass Timothy Canada bluegrass Zoysia grass Total - T o be presented at the 32nd Annual Northwest grass Conference, Holiday Inn, Richland, W A , September 25-28, 1978. Turf- These grasses were planted in 5' x 20' plots and mowed weekly at one inch, 2 inches, and 3 inches mowing heights. The annual fertility program consisted of 6 lb N , 2 lb P , and 4 lb K per 1000 sq ft. The grasses were irrigated as required for growth. Notes were taken on spring green-up, texture, color, and diseases. A summary of these scores is available from a separate handout. Kentucky bluegrasses with the best color (scores 8 or above) during the May-September period at the 2 inch mowing height were: Adelphi Aquilla Baron Bel turf Bonnieblue Continental Galaxy Glade Majestic Nugget Sodco Sydsport Victa The Kentucky bluegrasses generally have a better color score than do the fine-leaf fescues, although the cool fall period is favorable for excellent growth of the fine-leaf fescues. The perennial ryegrasses do exceptionally well in this area. They are almost equal to the Kentucky bluegrasses in turf quality. They do exhibit a lighter green color than the bluegrasses listed above. They probably have a higher N requirement than bluegrasses and look best at the 3 inch mowing height. The bentgrasses are maintained at lawn height (1/2 inchj] The species of AgsioAtù* show considerable differences in appearance. The texture of 'Velvet' bent is fine and overall quality is excellent. The cultivars 'Stranhem' and 'Penncross' perform well under these conditions. The bentgrasses are fertilized more frequently (8 lb annually) and watered and mowed bi-weekly during summer growth periods. require a 3 inch mowing height and 8-10 lb N annually to maintain desirable color. It is relatively drought tolerant and will green-up in the fall after prolonged summer drought. Zoysia grass is widely advertised in magazines in the Northwest as being hardy and durable. Tests after 2 years in this area of the Northwest indicate it is hardy, very tough to mow and produces abundant stolons. It is a transitional zone grass and becomes off-color early in the fall-winter and does not green-up until early summer. It desires long summer periods with 85-90°F temperatures. Diseases are not a critical problem with most grasses in this area with the exception of leaf-rust and HeJbnlnthoAposisLurrt leaf spot on some bluegrasses. Stripe sprout can also be a problem in some y e a r s . Winter snowmold diseases are destructive on all bentgrasses. 'Merion' bluegrass is very susceptible to leaf rust and some lawns exhibit a brownish color in the cool fall periods. Other bluegrasses also show relatively high degrees of rust although most new cultivars are highly resistant to rust. Grasses having high susceptibility Helmiyitko^po^um readings include: A d e l p h i , Belturf, G a l a x y , Kl-132, Prato, S i x , Sydsport, T r o y , Touchdown, V i c t a , Warren's A-34. Mowing height affects the quality of turf. Plots mowed at the 1 inch level generally are inferior in quality and color to those mowed at the 2 or 3 inch level. This is especially true using the rotary mower. The reel mower is much better for maintaining turf at the 1 or 2 inch levels. Cone!usions Turf managers have available many fine improved grasses for the Northwest. Many new bluegrasses are outstanding when managed properly. A l s o , the Northwest produces nearly 100% of the seed of these grasses; t h u s , high quality seed is available. The perennial ryegrasses do well in turf plantings in Idaho. They appear to exhibit good growth and acceptable color. Plantings observed for the past 6 years indicate they have sufficient winter hardiness for this area of the Northwest. Many fine-leaf fescues are likewise available. Although these grasses generally have more drought tolerance than Kentucky bluegrass, they do exhibit their best color and quality during the cool, moist and somewhat shady environments. Parma Location Twenty turfgrasses were established in April 1975 at this location. They included 15 selected Kentucky bluegrasses, 2 fine-leaf fescues, and 1 perennial rye which were all planted in a monoculture. A tall fescue-creeping red fescue mix and a bluegrass-creeping red fescue mixture were also included. These grasses were planted in 5 1 x 20' plots replicated three times. Each plot was mowed weekly at 1.5 inch and 3.0 inch mowing height. The plot area received 8 lb of actual N annually and was flood irrigated. Color readings were taken and are summarized in Table 1. These data indicate that the improved Kentucky bluegrass cultivars perform well under these conditions. The monoculture of the bent-bluegrass is superior to the mix of this grass with other species. The single perennial ryegrass did not produce as good color as most of the bluegrasses. The same can be said for the fine-leaf fescues. There is a general lowering of turf quality in this area as the summer weather progresses. These grasses improve in color and growth after mid-September and the cooler spring periods. No diseases were recorded in 1978 although rusts are usually abundant on most susceptible varieties during cool, moist periods. 00 cr> r— i o 03 -o t—1 c Scu +-> CO a; JEZ +-> o3 CO c •r— CO CU CO CO 03 cn •—> CO co cCJ> Osi O O C M O O C O r o m C M C O C O o O •r— \ -a CT» • • • • • • • • • • a N N V O N < O O O N N < £ > L N V O 03 CU s^ cr> LU _J CO Osi o in M CO co co CM r s r s ,— o > CU Saa Ol O3 03 ~a sS- r— CO CD CO 1 03 a O 03 CU a M C •rLiXI a a COa a CO 1 E a OS^ CD a C • 03 a a CO a CO 03 CU a • Xl CO a CO 4-> Xl cu CU -C a CO xi • CO xi a CO O3 Osi • CO CO i 3 Sa- O •O co a 1 co CO E O CU CO . • C XI a CO .XC co cu 3 03 CO • 03 4-> ^ S. ^ -O ^ % +-> S-.LJ- 4-> 4-> cu o M— r— • O 03 ^ sz -a S-.+-> +-> o s*. 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Please remember that until a special label is granted for the program outlined below, endothall cannot legally be used at the rates stated in this summary. Research at a variety of locations has shown that endothall has potential for Poa annua control in turf (1,2,3). Most researchers add that their tests did not result in long term Poa annua control, and that control has been inconsistent and unpredictable at best. Turgeon (3) also indicated that certain Poa annua variants appeared to be resistant to endothall. A general conclusion seems to be that endothall doesn't really work that well and its too "hot" to handle, meaning it may injure desirable turf. In searching for chemicals that might be suitable for Poa annua control in the Pacific Northwest I noticed that all research on endothall in the U.S. of America had been done under climatic conditions that are much more severe than we experience west of - T o be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, W A , September 25-28, 1978. the Cascade mountains in Washington and Oregon. For example Michigan and New Jersey where the most endothall research has been done are both characterized by hot humid summers and moderately cold to severe winters. Under these conditions turf is dormant during winter and is under considerable heat stress during summer. Turf normally goes through a spurt growth phase in spring and a smaller but similar phase in fall. In contrast the climate west of the Cascade mountains from the Willamette Valley of Oregon to the Canadian border is characterized by mild wet winters and moderate to hot dry summers. Turf normally grows at reduced rates through winter and enters an accelerated growth phase during spring that may continue through most of the summer and into fall. Prolonged severe stress periods are not common during either winter or summer. Periodic summer heat stress rarely lasts for more than a few days at a time. The end result is a relatively long growing season during which turf is under very littl stress compared to areas such as the Midwest and Northeast. We felt that our peculiar low stress environment might be more conducive to success with endothall and allow more variety in both rates and timing of applications, than the other areas where earlier research had been done. With that in mind we initiated research into the feasibility of endothall for Voa annua, control in the Pacific Northwest The summary and recommendations that follow are based on research and observations made over a three year period from 1975 through 1977. Additional work is ongoing. GRASSES The grasses commonly used in the Northwest were tested for tolerance to endothall. On a relative scale I would rank their tolerance as follows: HIGH TOLERANCE Kentucky bluegrass Perennial ryegrass LOW TOLERANCE Velvet bentgrass Fine fescues An interesting observation is that some of the chewing types of fine fescues such as Highlight and Jamestown showed good recovery from endothall treatments even though initial injury was rather severe. On the other hand no drastic differences in tolerance among varieties of Kentucky bluegrass, perennial ryegrass, or colonial and creeping bentgrass were noted. RATES Right from the beginning it was apparent that label rates were too low to be effective in controlling Voa annua as single treatments and caused unacceptable thinning of desirable grasses when used in repeat applications. Repeated applications were not always effective in enhancing Voa control since young undamaged tissue was often shrouded by dead tissue so additional sprays did not contact it. Based on my work I settled on the following rates for each grass: Kentucky bluegrass 2.5 kg ai/ha = 2.25 lb ai/A Perennial ryegrass 2.5 kg ai/ha = 2.25 lb ai/A Colonial bent lawn turf 2.0 kg ai/ha = 1.75 lb ai/A Colonial bent putting turf 1.25 kg/ha = 1.0 lb ai/A Creeping bent putting turf 1.25 kg/ha = 1.0 lb ai/A Velvet bentgrass putting turf - not recommended Fine fescues - not recommended, will survive 1 appli cation at 2.5 kg ai/ha ~ lb ai/A. In attempting to evaluate the effects of different rates of endothall on desirable grasses it became apparent that at rates that controlled Voa annua some discoloration of desirable grasses was inevitable. Most of the rates listed above will cause about a 2 point color loss on a scale of 1 - 9 . However, in all cases with the addition of nitrogen fertilizer, color returns very quickly. In my opinion this small loss of color is little price to pay for effective Voa annua control. While most testing was done on single species stands of t u r f , some tests were conducted on mixed swards. Kentucky bluegrass-fine fescue m i x t u r e s , for example, have been successfully treated with endothall at Kentucky bluegrass rates without severe loss or injury to the fine fescues. However, color loss in turf containing fine fescues is greater than in turf containing only tolerant species. SPRAY ADJUVANTS Spray adjuvants such as spreaders may be added to endothall without ill effects during optimum weather conditions. The addition of an adjuvant during cold weather or when frost is likely will increase injury to desirable grasses. When used properly spray adjuvants enhance Poa annua control at moderate endothall rates. Normal dilutions for adjuvants run around 1 to 800 (e.g. 1 pt/100 gal spray solution). SPRAY VOLUMES Most of my work was done using spray volumes in excess of 1000 1/ha or 100 gal/acre. I feel that uniform and thorough coverage enhances control and high spray volumes help in this regard. On the other hand success in the field has been achieved with spray volumes as low as 40 gal/acre. As a result it is difficult to say that high volumes of spray are necessary for control. TIMING Current label directions indicate early spring is the most desirable time for endothall applications. My work does not support this recommendation. On the contrary, I found that at appropriate rates for the grass being treated, endothall is most effective if applied when turf is growing vigorously without heat, c o l d , or drought stress. In the Pacific Northwest these general guidelines can be interpreted as follows: Kentucky Bluegrass Applications most effective when applied between early-June and mid-September provided general guide!ies are met. During summer avoid applications if day time temperatures exceed 85°. Perennial Ryegrass Same as for Kentucky bluegrass. I suspect ryegrass can be treated earlier than bluegrass but I have no data to back it up. Creeping and Colonial Bentgrass Applications are most effective between late April and mid-June and again during early-to midSeptember provided general guidelines are met. Summer applications are acceptable during mild periods when temperatures are below 80° and moisture stress is not a factor. CautionsSpring or fall applications when frost is likely will result in excess discoloration and injury to desirable grasses. Applications when grass is growing slowly such as mid-spring for Kentucky bluegrass may also result in excessive discoloration. REPEAT APPLICATIONS Endothall appears to be most effective on mature leaf and sheath tissue. Single applications often leave the apex and any developing young leaves uninjured. Follow up applications within 2 or 3 weeks often have little effect on this young tissue since it is enclosed in dead foliage. On the other hand the desirable grasses that withstood the first application are further weakened by the repeat treatment and may begin to thin. I chose to delay repeat applications until all grasses had completely recovered. This seems to allow maximum control of Poa annua with only minimum injury to desirable grasses. Empirical observations indicated that eight weeks was sufficient for this purpose. Therefore, I try not to make consecutive applications closer than about eight weeks apart. PRE-EMERGENCE HERBICIDES My tests and general field trials indicate that long term Poa annua control cannot be achieved with endothall alone. Endothall has virtually no soil activity and only a very short foliar residual activity period. Therefore reestablishment of Poa annua from seed is possible shortly after death of the original plants. In the course of my work I concluded that ultimate control would depend on either use of a pre-emergence herbicide to prevent reestab1ishment or overseeding with a vigorous grass in hopes of outcompeting the germinating Poa annua. All of my work depended on pre-emergence herbicides to add the final measure of control. I have no data on the real possibilities of over-seeding. The question of what to do after treating an area with endothall is important because there is no use in killing the Poa annua present unless something better can take its place. For this reason a short discussion of the potential of both pre-emergence herbicides and overseeding is included below. If people had a choice I'm sure most would choose to overseed after they killed the original Poa annua. The idea is a good one but it does have limitations. For e x a m p l e , given that Poa annua seed is also present, successful overseeding requires a vigorous germinating grass that can outcompete Poa annua from the start. Perennial ryegrass is probably the best answer to this problem but it may not be suitable for such areas as putting greens or bentgrass lawns where its color and growth habit do not blend in well with the other grasses. Bentgrasses also germinate very quickly but are very weak during the juvenile phase. As a result areas overseeded with bentgrass would have to be held out of play during establishment. Perhaps the greatest disadvantage of overseeding is that it means a gradual transition at best from Poa annua to the desirable grasses and will probably require several years of endothall treatments plus continuous overseeding to achieve desired results. Pre-emergence herbicides evoke controversy among many people. A continuing fear is that there is no way overseeding can be done if, for example, vandals strike or an accident occurs and turf is killed. Also there is a nagging fear that prolonged use of pre-emergence herbicides will cause decreased rooting and poor turf quality. To avoid such problems I feel pre-emergence herbicides need to be used intelligently. For example, as soon as the turf is thinned by killing the Poa annua, conditions are prime for germination. A pre-emergence herbicide is needed only from then until the desirable turf fills in vegetatively. Often the lowest effective rate of a pre-emergence herbicide can be used. My research indicates that bensulide, for example, is effective at rates as low as 8 kg ai/ha and is safe at least up to rates as high as 18 kg ai/ha. Therefore, when using bensulide for preemergence control it is safe and effective to use moderate rates such as 10 kg ai/ha (8-10 lb ai/A). An additional advantage of lower rates is a shorter activity period and less chance of any longterm negative effects on desirable turf. My data indicate that pre-emergence herbicides work very well with spreading types of grasses such as Kentucky bluegrass and bentgrasses. There is still a question in my mind as to whether or not they would be satisfactory for bunch-type grasses such as perennial ryegrass. In developing a long range program it may be desirable to adopt the best features of both overseeding and pre-emergence herbicides. For example, if a perennial ryegrass turf is heavily infested with Poa annua it might work best to overseed with ryegrass after initial endothall treatments in order to increase the percentage of perennial ryegrass. Once the ryegrass component is more uniform a preemergence herbicide could be applied prior to the next endothall treatment to speed up control efforts. FERTILIZATION Even though I can't offer strong evidence to support it I feel a strong nitrogen fertilization program is essential to effective Poa annua control with endothall. Normally this involves at least one application of a soluble nitrogen source (4-5 g N/ 2 m2 or 3/4-1 lb N/1000 f t ) before endothall to stimulate grass growth and a second application after endothall to stimulate fill in of treated areas. This approach is essential when using pre-emergence herbicides. It also appears to stimulate rapid recovery of color in the desirable grasses. CONCLUSIONS The above discussion can be summarized by outlining what I feel are effective programs for controlling Poa annua in different types of turf. I. Kentucky bluegrass and perennial ryegrass (Example for two treatments in one y e a r ) 1. MID MAY - Nitrogen - 40-50 kg/ha (3/4-1 lb/1000) LATE MAY - Bensulide - 10 kg ai/ha (8-10 lb/A) EARLY JUNE - Endothall - 2.5 kg ai/ha + X-77 (2.25 lb ai/A + X-77) 1-2 wks later - Nitrogen - 40-50 kg/ha (3/4-1 lb/1000) 2. EARLY AUGUST - Nitrogen - 40-50 kg/ha (3/4-1 lb/1000) MID AUGUST - Bensulide - 8 kg ai/ha (6-8 lb/A) EARLY SEPTEMBER - Endothall - 2.5 kg ai/ha + X-77 (2.25 lb/A + X-77) 1-2 wks later - Nitrogen - 40-50 kg/ha (3/4-1 lb/1000) The above program would allow maximum time for recovery and fill in during summer and again during fall. If necessary, however, treatments could be started at any time during the summer when weather is conducive. To achieve acceptable levels of Foa annua control, endothall will have to be applied more than once since single treatments rarely kill more than 60-80% of the Foa annua present. After two treatments in one year any treatments the following year could probably be held off until late summer or early fall. Once Foa annua is reduced to about 10%, pre-emergence herbicide applications are optional. II. Colonial bentgrass lawn turf (2-3 cm mowing ht) (Example for two treatments in one y e a r ) 1. MID APRIL - Nitrogen - 40-50 kg/ha (3/4-1 lb N/1000) LATE APRIL - Bensulide - 10 kg ai/ha (8-10 lb ai/A) EARLY MAY - Endothall - 2.0 kg ai/ha + X-77 (1.75 lb ai/A + X-77) 1-2 wks later - Nitrogen - 40-50 kg/ha (3/4-1 lb N/1000) 2. (Optional depending on success of first treatment) MID AUGUST - Nitrogen - 40-50 kg/ha (3/4-1 lb N/1000) LATE AUGUST - Bensulide (opt) 8 kg ai/ha (6-8 lb ai/A) MID SEPTEMBER - Endothall - 2.0 kg ai/ha + X-77 (1.75 lb ai/A + X-77) 1-2 wks later - Nitrogen - 40-50 kg/ha (3/4-1 lb N/1000) The approach after the first year of treatment would be similar to that for Kentucky bluegrass or perennial ryegrass. Eventually applications could be made on an as needed basis. III. Colonial or Creeping Bentgrass putting turf (4-6 mm mowing ht) EARLY MAY - Endothall - 1.25 kg ai/ha + X-77 (1 lb ai/A + X-77) 1-2 wks later - Nitrogen - 40-60 kg/ha (3/4-1 lb N/1000) If necessary the above treatment sequence could be applied in the fall so that the endothall treatment would be applied before mid-September. On putting turf I hesitate to make more than one application per year to avoid excess stress. Because the lower endothall rates used result in poorer Vocl annua c o n t r o l , annual applications would probably be required for 2 to 3 years to achieve desirable control. T h i s , of c o u r s e , depends on the individual site involved. REFERENCES 1. Engle, R. E. and R. J . Aldrich. 1960. Reduction of annual bluegrass, Poa annua, in bentgrass turf by the use of chemicals. Weeds 8(1): 26-28. 2. McMaugh, P. 1970. A desiccant approach to Poa annua control. J . Sports Turf Res. Inst. pp. 63-75. 3. T u r g e o n , A . J . 1971. The role of 7-oxabicyclo (2.21 heptane 2,3-dicarboxylic acid (endothall) in annual bluegrass {Poa annua L.) control in turf. Ph. D. T h e s i s , Michigan State University. 101 pp. TURFGRASS RESEARCH REPORT1 Alvin G. Law2 The turfgrass variety trials at State!ine, Idaho, established in 1975 in cooperation with Jack!in Seed Company, were observed for color, disease resistance, and winter survival. We are growing 25 ryegrass varieties, including all of the available fine-leaved 'turf' types as well as the older coarse-leaved varieties. Of considerable interest is the fact that all varieties have survived two relatively normal winters with no evidence of any winter damage. Some of the same varieties in seed production fields in the same general area have winter-killed consistently. I have no explanation of the evident winter hardiness of close clipped turf compared to the lack of winter survival when the same varieties are allowed to produce seed. The fine-leaved 'turf' types consistently had a dark green color compared to the light green color characteristic of the wide-leaved coarse types and thus would blend better with Kentucky bluegrass, the dominant general purpose turfgrass in the Inland Empire. Moreover, density readings were higher for the 'turf' type ryegrasses. The 31 Kentucky bluegrass varieties in this trial showed expected differences in density readings with the tall growing types such as Delta and Park having much less dense turf than the low growing varieties typified by Nugget, Glade, Bonnieblue or Victa. There were some differences in Hehn^ntko¿posUum tolerance with Delta, Park, Plush, and — To be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, WA, September 25-28, 1978. 2/ Prato having more damage from this disease. In contrast, Warren turf selections A-20 and A-34, and Nugget, Majestic, and Aquilla were only slightly damaged. Mixtures of bluegrass varieties with creeping red fescue greatly reduced the amount of HeXmintko^po^Uum damage. There was no discernable difference in turf quality or density in these mixtures clipped at one inch in height. A second research effort has been with annual bluegrass. We used endothall and bensulide in various combinations on Kentucky bluegrass turf that had a 25 to 50 percent annual bluegrass contamination on the A.S.S.C.W. golf course fairway No. 6. The treatments were applied in late June 1978. Bensulide was applied at 8 , 12, and 16 lb a.i. per acre across plots that were later treated with endothall at 2, 2.5, and 3 lb per acre. Both treatments were applied as water solutions and a stickerspreader was included as a treatment with the endothall applications. Plots were rated for control of established annual bluegrass or for control of reinvasion by annual bluegrass seedlings using a 1 to 9 system. First year data are shown in Table 1, Reinvasion of the treated areas by Poa annua. Here the effect of bensulide on controlling re-establishment of the weed becomes clear. There was essentially no re-establishment of annual bluegrass on any of the bensulide treatments, average readings of 1.8 on a scale where 1 = no seedlings at all. Compare this with the average readings of 5.05 on all the 0 bensulide plots. As was expected, endothall had no effect on the reinvasion by annual bluegrass seedlings. Table 2 shows the first year effect of endothall on established annual bluegrass. We would emphasize that first year data must be considered as preliminary and the plots must be read again next year. There was a highly significant reduction in annual bluegrass for the 2.5 and 3.0 lb of endothall compared to the check. There were no differences in the amount of established annual bluegrass left in the plots on the bensulide treatments. We think there is sufficient perennial bluegrass (Merion variety) present in the plots so that by next spring the recovery will give us a good cover of grass. Reseeding obviously cannot be a help because of the bensulide treatments, so it is important to start this control program before the perennial bluegrass is damaged beyond recovery. CD O) 03 co o co • LO X 1—• o• PO PO CO CO LO LO LO LO ou o ou LO X ou ou ou • • • CO PO • LO PO• LO LO X• LO C\J ou C O LO CO L LO O PO LO • • • 1 — r — i — C\J O• PO• LO• LO• PO• ou LO Ol• r— LO CO CO CO co ou LO OU r— r— 00 X r— CD c o c: CD Ol 03 s^ CD > 03 CO o o CD TD 13 C CD C Û 00 03 CD JZ s*. 4 > O O 03 TD X C -Q ou ou ou — i ou X X X + LO • ou OU • — r— X X X + LO• OU PO -o CD CD cn o il cu CD rd SCU > < C 4-> C CD E 4-> rd CU 4-> CU +-> M— rd CO >> rd -O x co co rd CD CU r— -Q r— rd C c rd <4O r— o 4-> c o CJ • C\J LU —I CO I rd O X TD -Q £Z r— LU O • LO O LO LO o co CD 1— X co • • • • • CO LO co 00 LO• 00• o • co 00• co LO• LO• co 00 o LO• co 00• 00• co co • • co 00 co 00• co o co • 00• LO• 00 00 co • LO 00 LO • • co co co • • co 00 • • • x x X + Osj CM • X X X + LO• LO• C\J Osi co cu c o cz 00 1—• LO 00 X• LO CD• o• IO cu cr> rd scu > < TURFGRASS DISEASE RESEARCH REPORT1 Gary A. Chastagner, Roy L. Goss, Worth Vassey and John M. Roberts2 RESIDUAL ACTIVITY OF FUNGICIDES AGAINST RED THREAD A fungicide test plot was established on putting green turf containing a mixture of 'Highland' bentgrass and Voa annua at the Western Washington Research and Extension Center's Farm 5 , Puyallup, W A . Applications were started on September 2 6 , 1977 and repeated at 2 or 3-week intervals until May 10, 1978. Fungicides were applied in 10 gal of water 2 2 per 1000 f t to six replications of 25 f t each. Rates and formulations of fungicides used are shown in Table 1. The wettable powder formulation of CGA 64251 was used initially with the first application using the emulsifiable concentrate formulation being applied on March 10, 1978. This test was initiated to test the effectiveness of these fungicides in controlling F u a o j v L u î y \ patch. Although no FuAcwium patch developed within the test plots through M a y , we did obtain information about the residual activity of these fungicides against red thread. -^To be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, W A , September 25-28, 1978. 2/ - A s s i s t a n t Plant Pathologist, Agronomist/Extension Agronomist, Agricultural Research Tech. Ill, and Turfgrass Research A s s o c i a t e , Western Washington Research and Extension Center (WSU), Puyallup, W A . Red thread developed throughout the test plot in June. Table 1 shows that Rhodia's RP 26019 and Ciba-Geigy's CGA 64251 effectively prevented the development of red thread 40 days after the last application of these fungicides. The highest rate of CGA 64251 applied every 2 weeks caused a reduction in turf density and resulted in a dark bluegreen colored turf. Current tests are evaluating the extent of residual activity of selected fungicides against FuócuUum patch and red thread. We have also initiated a test to determine if these fungicides have any effect on the rate of nitrification following applications of urea. Dark Green Depressed Circular Spots: A disease of unknown cause appeared on the bentgrass varieties under advanced management at Western Washington Research and Extension Center's Farm 5 during June. The symptoms of the disease are: 1. Dark green circular spots up to 10 inches in diameter. These spots often coalesce. 2. Thatch is decomposed under the spots which results in the center of the spot being depressed. 3. The turf is easily lifted from the surface beneath the spot. This is the fifth year that the bentgrass varieties have been under advanced management. Each variety is replicated three times and consist of 100 f t 2 replication. Each variety receives nitrogen at 5 and 10 lb per 1000 f t 2 . Turf receiving both levels of N also receives alternating applications of Fore and PMAS throughout the year. Table 2 shows that the percentage of turf covered by these spots varies between bentgrass varieties, but is generally less prevalent on turf which received applications of fungicides and/or high levels of nitrogen. The percentage of turf area with this disease has increased throughout the summer months. Because of the depressed nature of the spots, the turf texture within the spots is rough. Isolation of Causal Agent: Results from initial attempts to isolate the causal agent were inconsistent. By placing sections of turf removed from the margin of the spots into moist chambers, white spherical masses of hyphal tissues developed in 2-5 days. The hyphal tissues from these structures were isolated on a variety of media which contained antibiotics to surpress bacterial development. The fungus consistently isolated in this manner is a basidiomycete as evident by the presence of clamp connections. The isolated fungus grows optimally at temperatures between 68-86°F on potato-dextrose agar. However, even at these temperatures it has only grown .3-.4 inch after 8 days. Inoculum is being increased on wheat seeds so that pathogenicity studies and other tests can be performed. JD >> •-M r— CeO cu Q "O AS CsU JZ -a eu s4O r— Os+-> e o (J So 4 3 A>3 LU • LU CÜ r— CO ea o r— i— Q03 £D> 0 3 Scu E -M C U e CU M TD >> +-> E A3 O 4Een en E CU sA3 e. CU CO CM CO CM CM CO CO CO CO CO CO 1 4-> 4-> CU i— ECU eA3 n CU se cu -Q >> • • • • A3 A3 03 A3 M O en en en en 00 CoM oC M o L O N O SD •R— M O A3 LO X O en o N O CM CM 00 TD A3 en LO N O 00 -M A3 3 CD CD CD CD LU LU LU oL U O LO LU o o S- o S- SO o S- +-> CL. 3 CL 3 CL 3 — , , CL. CL 3 E CU CÛ 3 O LO OD O LO CM Q_ CC LO CM LO CM LO CM LO CM LO LO LO Q. E CD O o LU CU S- 4-> E CEU 4O-S> C EU f— cu 44- 4-> o +-> CM+-> 4O O O i— Xcu 4-> 03 CU O• O II CL +•> 0 3 eu c. 0300 X 4C->"»— r— euLO o scuLO CL CM bed 4-> 3 CL E O a; E So 4•r— O 3 4E 3 •f— O 4-> SoO O LO cd CD E CM be 43 +-> 00• 00 en E A3 OE =3 Q A3 3 O LO X so CL — ,3 3O LC OM 3O CU +-> 00 L O 00 AS r— cu cu CJ E s- e S - cu CU o CC DJ LoL -E CO LL CD CU S O r— O 4en E E 3 i— Oo • r—+J A3 en CJ 4-> CU SO 4— "O E A3 +-> en i— 3 4E CU CU Scn s- A3 "O II CT» O 4-> +•> O a cu A3 JD E^ OsJD 1 ^ O i— CU >> II 1 — E O "O cu en A3 JD een n E -M >, A3 I— OC CU > •r— • 4-> 00 CJ X CU X Q^ j- en CM X cu s>> +-> OE Ten Scu- Cen U E E > E CU -aCU A3 CE A3 TD •r4-> cu E en e n A3 E Q_ en CU •i— E eJD p-M 'r- O E — 4-> r— 13 E3 A3 O ^ OC CJ JD A3 +-> TABLE 2. Effect of bentgrass variety, fungicide application and nitrogen levels on the percentage of turf area with dark green depressed circular spots. 5 Variety Percent area showing symptoms Without fungicide With fungicide High N Low N High N Low N SEEDED: Bardot 3.0 4.8 2.8 4.0 Boral 2.0 4.8 0.0 2.3 Highland 0.0 15.5 0.3 4.5 4.5 8.0 10.3 Kingstown 1.8 Novobent 0.5 4.8 1.3 5.8 Penncross 5.3 12.5 0.3 6.0 Prominent 5.3 11.5 2.5 3.8 Emerald 3.5 7.5 3.8 3.8 Tracenta 2.0 8.3 5.5 6.0 A-75 4.3 12.3 3.0 5.3 Rusta 0.0 0.5 0.0 2.5 Aggrettina 0.0 0.3 0.0 0.3 Tendenz 0.0 0.5 0.0 5.0 PSU-PBCB 0.0 0.5 0.5 3.0 Ariington 3.0 11.8 0.3 4.8 Nimisila 22.5 31.3 6.8 5.5 Northland 17.3 36.3 9.3 14.5 Waukanda STOLONIZED: 16.0 12.8 4.3 18.3 Yale 0.8 13.0 0.8 19.3 2.0 Keen's 36 1.5 4.3 0.0 Arrowwood 3.5 10.5 1.5 7.3 MCC-3 0.5 3.0 0.3 2.3 UCR-30 3.8 5.5 4.3 5.0 Penn #5 5.0 5.3 0.8 4.0 Smith 721 1.3 8.0 0.0 2.8 Smith 732 1.3 4.5 0.3 1.3 Smith 736 0.8 10.0 1.0 3.5 Hayden Lake 2.0 6.3 0.0 2.0 a Data taken on September 11, 1978 GROWTH REGULATORS ON ESTABLISHED TURF 1 John M. Roberts and Roy L. Goss2 The desirability of maintaining a healthy low growing turfgrass cover without frequent mowing is something that most turf managers would appreciate. There are basically two areas of research attempting to accomplish this low growth either by (1) breeding of low growing turfgrasses, or (2) using growth regulators. PROCEDURE Three growth regulators, Maag RO 7-6145/001 (6,9,12 lb/A), Embark (0.25,0.50,0.75 lb/A) and Sustar (1 gal/A) were applied on July 24, 1978 on an established 'Highland' bentgrass turf at the Puyallup Research Station. The plots were mowed at 2.0 cm four days prior to the application of the growth regulator and received irrigations thereafter to maintain healthy plant cover. Color and plant height readings were recorded 10 and 30 days following application (Table 1). RESULTS AND DISCUSSION All the growth regulators reduced the growth of the bentgrass (up to 45 percent) as compared to the control. In general as the reduction in plant growth increased, the color ratings decreased. For example, the product, Embark, at all three rates resulted in the greatest reduction in bentgrass growth as compared to Sustar or the Maag R0 7-6145/001 products; however, Embark also obtained the poorest color ratings. - T o be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, WA, September 25-28, 1978. 2/ -P E E: A 0 3^ r- -p A _ JE -p E IX 00 X 00• • X LO o Od co • • • co LO X X • X X • CT X X o o • • co X o • co o • CT o• CT co c\i Od 1— Od • • • Od Od Od co • co co X X • • X X co o • • co CO X • CO 00 00 o O • • CT Od 1— LO Od• o o LO LO• X • o o r— A3 CT • O CO o E o co 4 > F Ö A; S4-> 5- -P E aj e o -P M - 03 —' F Ö C O fÖ r Q o o O CD CD -p A3 JD r— Cd • • o • 00 00 00 co • co X • co o • co • 00 • • 00 • o • CT o o LO •p o 3 -O o a_ r— CO 1 X o DC CT A3 A3 Z SA3 -Q E LU rö •P 00 3 00 — , O •p c: o o CT c •r— -P fÖ So I— o o A NEW PLANT GROWTH REGULATOR WITH POTENTIAL POST EMERGENCE POA ANNUA CONTROL? 1 John M. Roberts and Roy L. Goss2 A new plant growth regulator, MBR 18337, at rates of 0.375 to 0.75 lb ai/A has been reported to show plant growth retardation and seedhead suppression on Kentucky bluegrass, tall fescue and common bermudagrass. Poa annua retardation has also been reported in established bluegrass sod in Northern California. Certainly any product having the capacity to suppress or eliminate Poa annua in established turf is of interest for future research testing. MBR 18337 was applied at rates of 0 . 1 0 , 0.40 and 0.70 lb ai/A on various established bluegrass varieties on July 12, 1 9 7 8 , at the Puyallup Research Station. The test area received no additional irrigation and the bluegrass sod was under a moisture stress throughout the majority of the testing period. The Poa annua (Table 1) was also showing moisture stress symptoms and in general had a w e a k , off-color appearance. The MBR 18337, especially at 0.70 lb ai/A caused a further weakening of the Poa annua without severely impairing the bluegrass color and appearance. However, at no time in the testing period did the MBR 18337 "kill" or severely retard the already weakened Poa annua. -Jo be presented at the 32nd Annual Northwest Turfgrass Conference, Holiday Inn, Richland, W A , September 25-28, 1978. 2/ After 40 days following application bluegrass height reductions of 1 to 2 inches were recorded as compared to the control and only minor reductions in color ratings were observed at all the application rates. MBR 18337 was applied at rates of 0.10, 0.40 and 0.70 lb ai/A to a healthy established 'Highland' bentgrass sod mowed at 0.75 inch on July 12, 1978 (Table 2). This area received irrigation as needed to maintain a vigorous turf. Two days after application one-half of the plots were mowed (Table 2 ) , as reports indicated that this practice enhanced the MBR 18337 activity on retarding plant growth. In this test there was little to no advantage of mowing following the herbicide application as indicated by the color and plant height data in Table 2. In general only minor reductions in the color ratings were noticed and the bentgrass growth was reduced 1 to 2 inches as compared to the control 40 days following the herbicide application. 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