hallenges for turf grass maintenancehave been a constant in the golf courseindustry since its beginnings. In recent

years, maladies that used to be viewed asnuisances, curiosities, or annoyances haveemerged as full-blown turf management issues.Major turf grass problems still occur on golfcourses, but more time seems to be spent dealingwith these "little problems" than ever before.The increase in these problems coincides withincreasing golfer expectations, but golfer expec-tations alone cannot explain why these problemshave emerged. Although everything is relative,golfer expectations have always seemed to trendtoward the high end of the conditions that can bemaintained on golf courses. Interestingly, someof these problems are some of the most difficultto control and explain. Certainly, the emergenceof these problems is complex and likely the resultof multiple management factors.

Diseases such as fairy ring have occurred moreoften or at least have garnered more attention in

recent years. This disease has created aestheticand playability nightmares on many golf courses.Cultural and chemical treatments are very effec-tive or else completely ineffective, dependingupon factors that are not completely understood.More research is being conducted to betterunderstand fairy ring because of its emergenceas a significant turf problem. Soil diseases suchas root Pythium dysfunction and take-all patchare difficult to control once they are active.Creeping bentgrass collars decline uncontrollablyduring the heat of summer. In some instances,more conservative maintenance practices inconjunction with intense fungicide programsprovide little relief

Localized dry spots (LDS) seem moreprevalent than ever during any periods withbelow normal rainfall, requiring more handwatering. Earthworms and ants cause turf grassdamage through casting and mounding of soilthat create major issues with playability, appear-ance, and maintenance. Earthworm control is

The intensity ofmaintenance at higherbudget golf courses hascreated a standardwhereby any blemish iseasily noticed. Maladiesthat may have beenpresent in the past, butwent unnoticed bygolfers because turfquality was inferior, arenow easily picked out.

JANUARY-FEBRUARY 2009

Inconsistent dewpatterns may be an earlyindicator of localizeddry spot. Localized dryspots create watermanagement challengesthat require frequenthand watering toprevent turf decline.This condition hasbecome more of anissue in recent years asmanagement practiceshave changed to meetgolfer expectations.

illegal and controlling nuisance ants in fine turfareas is an ongoing battle.

These are just a sampling of some old prob-lems that have emerged as major challenges ineveryday turfgrass management. If we couldtruly define the root cause of these issues, main-tenance programs could be changed to limittheir impacts on turf quality. Unfortunately,pinpointing a single reason why these problemshave emerged is extremely difficult. Of equalfrustration is trying to explain why these prob-lems occur on some golf courses, or even specificareas of an individual golf course, but not onothers, in spite of maintenance programs andother factors that are summarily the same. Thereare many variable factors that may contribute tothese problems. This article will not serve todefine control options for these issues. Rather,it will explore some of the changes that haveoccurred in turf grass management that may helpto explain the emergence of these problems,helping to mitigate their impacts or at leastallow some acceptance of these maintenancechallenges.

GRASS SELECTIONGrass selection for golf courses plays a role inthese "new" problems, especially in the transitionzone regions of the country. As our ability toprovide excellent playing conditions with cool-season grasses in warmer climates has improved,these grasses have been pushed into regions that

2 GREEN SECTION RECORD

provide tremendous challenges during times ofsummer stress. Creeping bentgrass varieties forputting greens, especially, have been pushed intodifficult areas with expectations that cannot beprovided. The idea that perfect playing condi-tions can be maintained during times of thegrowing season when survival of the grass is abetter goal is not realistic. Technologicaladvancements cannot overcome physiologicallimitations of the turf grass under certain condi-tions, yet we often expect them to. Increasedmanagement intensity on grasses that are pushedto geographical limits during periods of maxi-mum environmental stress creates a potentialopportunity for even weak pathogens and peststo create major turf grass problems.

CHEMICAL CHANGESChemical pesticide options that are available

for use on golf courses are more numerous thanever. Our understanding of how these chemicalswork is more complete because the screeningprocess for their registration is more stringent.However, many of our commonly used chemicalshave site-specific modes of action that targetspecific insect or disease organisms. Manyinsecticides currently used on golf courses areonly effective on a specific growth stage in thelife cycle of an insect pest, so timing is critical.Non-target effects are minimal compared toolder chemistries; persistence in the soil ofcontact insecticides is short, and some are tightlybound to organic matter, which may furtherreduce potential non-target activity. Broad-spectrum activity, high toxicity to target pests,and long soil residual are a strong combinationto provide good pest control for a long time.Most of our existing insecticides lack this com-bination of characteristics.

Earthworms are an indicator of healthy soiland provide many benefits for the turf However,earthworm castings play havoc with maintenanceand playability. In the case of earthwormdevelopment, earthworm suppression was a sideeffect of insecticide products that are no longeravailable. One specific example is the insecticidechlordane. Chlordane and related compoundswere very effective against a wide variety oftargeted insect pests and some non-targetorganisms, including earthworms. The meanhalf-life of chlordane (the time at which half ofthe chemical degrades in the soil) is reported bythe EPA to be 3.3 years. Half-life of chlordane

varies by soil type because it is tightly bound tosoil particles. Thus, a single application ofchlordane could provide residual control of soil-borne pests for several years. Frequency of appli-cation varied by the pest targeted. If chlordanewas applied every other year in a five-yearperiod, prior to application in the fifth year ofapplication, soil residual would be slightly higherthan the initial rate of application. With the yearfive application, the residual in the soil would bedouble the initial application rate. Dependingupon the interval and rate of application, chlor-dane could remain in the soil at rates highenough to maintain continuous control ofvarious pest problems.

Other insecticides that research showed to betoxic to earthworms, including bendiocarb(Turcam) and ethoprop (Mocap), have been dis-continued for use on turf Research has shownthat one of the side effects of insect controlapplications with these products was earthwormsuppreSSIOn.

Similarly, the elimination of mercury com-pounds and other fungicide products has changeddisease control, especially for some of our hard-to-control diseases such as take-all patch. Mer-cury provided control options for a lot of diseaseswith a single product, with little chance forresistance. The elimination of these compoundsmay be partly responsible for the surge in fairyring problems on golf courses over time as well.

The discontinued use of all of these productsfor the betterment of the environment was apositive step for golf courses, but it is likely thatside effects of some of those products helped tocontrol non-target problems. The removal ofthose products from the market is one factor inthe emergence of some of the problems that weare now expenencIng.

IRRIGATION PRACTICESWall-to-wall irrigation coverage on golf coursesis becoming more of a standard than a luxury.Frequency of irrigation has increased on mostgolf courses in the past 20 years. Irrigation of thenear rough and green surrounds is considered amust on many golf courses. Increased irrigationhas improved the appearance of fine turf areas,but could our penchant for green turf, in com-bination with firm, fast conditions, be contribut-ing to some of the persistent problems that arebeing experienced at certain times during thegrowing season?

Cool, moist soil conditions certainly encour-age earthworms and provide a perfect environ-ment for casting activity. Irrigation prolongsthese conditions for earthworm development.Our irrigation practices may also encourageother problems such as fairy ring and LDS.

Fairy rings take on various appearances inturf Sometimes, only superficial symptoms areexpressed as a dark green ring of turf This iscaused by nitrogen release during the breakdownof organic matter as the fungus develops. Some-times, the rings are only annoying aesthetically.Other times, the turf grass at the edge of the ringdeclines because of excessive nitrate release underhigh temperatures. More commonly, waterrepellant soils develop and create drought stresson the turf around the rings.

The basidiomycete fungus that is the maincause of fairy ring thrives under moist conditions,as do most fungi. Many golf courses irrigate turfon a frequent basis, and this maintains an envi-ronment in the upper portion of the soil profilethat aids in development of fairy ring and otherdiseases. Massive fairy ring development hasbeen noted after heavy rain, again pointing tothe importance of water in development of thisproblem. Under dry weather conditions, irriga-tion inputs keep the grass green but are notadequate to prevent wilt stress from occurringin the turf as a result of fairy ring.

Deep, infrequent irrigation is often the goalof irrigation cycles, and this provides benefits interms of playability and disease prevention. Irri-

Severe fairy ring cankill grass in spite offungicide applications.Killer fairy ring has beenmore common in recentyears, possibly fueled byirrigation and othermanagement practicesthat encourage itsdevelopment over time.

JANUARY-FEBRUARY 2009 3

gation is applied heavily to thoroughly wet thesoil, and the soil is then allowed to dry downbefore additional irrigation water is applied.Unfortunately, research suggests that LDS isencouraged partly by repeated wetting anddrying cycles. With each drying cycle of thesoil, organic acids coat soil particles and thiseventually leads to hydrophobic conditions.Again, some of our accepted management prac-tices may have some unintended consequenceswhen they are implemented as the seasonprogresses.

GOLFER EXPECTATIONSThe common denominator that brings togetherall of the above issues is golfer expectations. Thegoal of any turf grass management program is tomeet the expectations of golfers while maintain-ing aesthetically pleasing surfaces. Golfer expec-tations are as high as they have ever been, andthis is not a complaint or an excuse; it's a fact. Itmay come as a surprise to some that many of themaintenance programs that are used on golfcourses are a compromise between keeping theturf grass alive and providing the conditions thatgolfers expect and demand. Changes in irriga-tion practices mentioned above are directly

Earthworm casts createchallenges for mowing and

playing quality. Heavyearthworm casting can turnfairways to mud in a matter

of days. Peak castingactivity in spring and fallalso coincides with peak

golfer activity, whichhighlights the damage thatoccurs and the frustration

that comes with it ..

4 GREEN SECTION RECORD

related to expectations, and there are otherlogical relationships between golfer expectationsand the emergence of many turf grass mainte-nance problems.

Most golfers agree that the appearance andplayability of golf courses are more uniform andconsistent than they were in the past. Thus,when blemishes do occur, regardless of the causeof the problem, they are more noticeable. Whenproblems are noticed, solutions to cure them aresought. Some of these problems may have beenignored or tolerated in the past, but not any-more. At the same time, these problems areoften at their worst at the times of the growingseason when the turf is least able to tolerateadditional stress. Consider that five percent turfloss spread around a putting green would yield asurface considered unplayable by the moderngolfer. This simply indicates the level of qualitymaintained today.

Low mowing heights also are a contributingfactor, causing great physiological stress on theturf With less leaf tissue, photosynthetic capacityand thus recuperative potential is reduced.Higher-cut turf can mask problems that are sonoticeable in fine turf areas. For example, antsand earthworms live in golf course rough just as

happily as they do in tees and fairways. However,ant mounds and worm casts have little impact in3-inch Kentucky bluegrass rough compared tocreeping bentgrass fairways mowed below one-half inch.

Nitrogen fertilizer rates often are kept low inan effort to promote green speed, which makesthe grass more susceptible to diseases such asanthracnose. Water is withheld to producefirmer conditions, but doing so may furtherstress the grass. Greens are mowed and rolledmore frequently, placing additional mechanicalstress on the turf grass. The decline of collars thatis frequently experienced during the summermonths is directly related to traffic intensityfrom equipment used to prepare greens for dailyplay.

These practices can jeopardize turf grass healthat any time of the year, but they are especiallydamaging when environmental stresses are high.Sometimes, brown grass provides excellent play-ability, but there is an expectation for golf coursepresentation that often overrides playability. Thisdesire for green turf is often in direct conflictwith playability goals set forth by green commit-tees and course officials. Firm, fast, and greenare difficult to achieve, especially during themost stressful portions of the growing season.The result is turf grass that is under tremendousphysiological stress; that is less able to resistdisease, insects, etc.; and that is less able torecover from damage that occurs. The closer thegrass is to "the edge," the more susceptible it will

be to pathogens that may not otherwise be aproblem. Interestingly, some of these problemsthat are a major issue on very intensely managedgolf courses are nothing more than a passinginterest on lower-maintenance golf courses thatdo not have the resources to push grasses to theirlimits. Expectations are lower at these facilities,and with the exception of problems on puttinggreens, problems with LDS, earthworms, fairyrings, etc. are ignored or at least accepted.

No single factor is to blame for the emergenceof old problems and the development of newones as major management challenges. The lossof certain pest control chemistries has affectedcontrol of diseases, insects, and other organisms,such as earthworms, and has challenged theresourcefulness of superintendents and agrono-mists to develop solutions. The level of mainte-nance provided on golf courses, especially as itrelates to irrigation, has allowed better turf grassquality to be maintained, but it may also providea better environment for some emerging prob-lems to persist. For sure, golfer expectations havecreated a heightened awareness of certain issueson fine turf areas. Maintenance challenges ofone kind or another have always existed on golfcourses, and we must continue to develop strate-gies to meet these challenges and keep up withthe ever-changing expectations of golfers.

DARIN S. BEVARD is a senior agronomist in the Mid-Atlantic Region if the transition zone, which isfertileground for the emergence if management challenges.

As height of cut hasbeen reduced on fineturf areas, problemssuch as nuisance antmounds are all the morenoticeable in terms ofplayability. They causemore injury to the turfbecause lower-cut turfis easily smothered byant mounds.

JANUARY~FEBRUARY 2009 5