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continued Cover StoryBanner Maxx(propiconazole)DMI applied at 2 gal./1,000 ft 2alt TE (0.125 fl. oz./1,000 ft 2 )Aug. 24, 2011. Virginia Tech G.C.Bayleton SC(triadimefon)Eagle EW(myclobutanil)QP Tebuonazole(tebuonazole)Tourney(metconazole)TriadimefonLike propiconazole, triadimefontypically provides great control ofdollar spot. Longevity of controlmay be slightly shorter than propiconazole,but it may have slightlymore activity against brown patch.One of the key attributes oftriadimefon is that it is one of themost effective active ingredientsfor managing fairy ring. It is oftenused in early spring to delay onsetof both dollar spot and fairy ring.Also like propiconazole,triadimefon can regulate bentgrassesand annual bluegrass onputting greens, and it can openthe canopy for algae development.MyclobutanilMyclobutanil is not used asfrequently today as it was in thepast. This active ingredient is notas effective as propiconazole ortriadimefon at controlling dollarspot, but it is probably more usefulfor controlling brown patch. Oneof its main uses is for managingspring dead spot of bermudagrass.The regulation mentioned aboveis often not nearly as distinct withmyclobutanil.Trinity(triticonazole)Triton Flo(triticonazole)Figure 2. Comparison of DMI fungicides alone and in rotation with trinexapac-ethyl(Primo Maxx, 0.125 fl. oz./1,000 ft 2 ) on annual bluegrass putting greens using RVI.Higher RVI values correlate to greater turf health. Rates tested are low rates from Figure 1.In many ways, this activeingredient has similar attributesto the newer DMIs. Myclobutanilis one of the more common activeingredients found in fungicidesmarketed to homeowners.FenerimolThe most common use of fenerimolover the last two decades hasbeen for spring dead spot controlon bermudagrass. This activeingredient has been the industrystandard over products such asmyclobutanil and azoxystrobin.With the availability of tebuconazoleand metconazole as comparablealternatives, Gowan Company(manufacturer of Rubigan) announcedin September that itwill no longer sell fenerimol foruse in turf, beginning in 2013.Metconzole, tebuconazoleand triticonazoleEach of these active ingredientshas similar attributes for use inturfgrass. Each provides moderateto great control of the three mostcommon diseases: dollar spot,brown patch and anthracnose.These three active ingredientstypically perform similarly for controllingmost diseases and impactingturf quality. In most studies atVirginia Tech, metconazole andtebuconazole typically have thehighest quality ratings (both visualand with reflectance plant healthindices) among all DMIs (Figure1), with triticonazole usually beingclosely behind.In several situations (data notshown), triticonazole has outperformedpropiconazole considerablyafter repeat applications. Researchat Virginia Tech has shown thattriticonazole (Trinity and TritonFlo) suppresses algae, unlike mostother DMI fungicides.Tebuconazole is registeredfor use only on golf courses atthis time, with a limitation ofsix applications in a calendaryear. The most common uses ongolf courses are for control ofanthracnose, spring dead spotand fairy ring.Metconazole does not haverestrictions on the label for siteuse and can be applied up tofour times per calendar year atthe highest rate (0.37 oz./1,000ft 2 ). Uses on golf courses arecomparable to tebuconazole,and the product is frequentlyused by lawncare operators aspart of their brown patch controlprograms for commercial andresidential properties.Turf health and qualityWe have evaluated each of theDMIs under multiple growingconditions at Virginia Tech forimpact on turf quality. The mostcommon focus has been ongolf putting greens, since mostinjury is observed under thesecircumstances.One study compared each ofthe turf DMIs at various rates,based on reflectance measurementsused to quantify stressprior to symptom development.Fungicides were evaluated alone,when rotated with trinexapacethyl(Primo Maxx, 0.125 fl. oz./14| VIRGINIA TURFGRASS JOURNAL January/February 2012 www.vaturf.org
Cover Story continued1,000 ft 2 ) and when watered intothe canopy immediately afterapplication. Reflectance datafrom visible red and near infraredregions of the electromagneticspectrum were collected andused for calculating simple ratiovegetation index values (RVI).Figures 1 and 2 show a portionof data generated from this study.While reflectance measurementswere higher with tebuconazoleand metconazole, none of theplots were objectionable. In mostcases, higher rates actually hadhigher RVI values, indicatinggreater health (Figure 1). Alternationwith trinexapac-ethyl didnot negatively impact the performanceof DMIs, and accordingto these data, it may actuallyimprove quality of Tourneyand Trinity.SummaryThis group, as a whole, has manybenefits for turf managers. Withthe newest additions to the class,many diseases are controlled moreeffectively, with others still beingsuccessfully controlled with olderchemistry.Over my career, I have evaluatedthousands of plots that havebeen treated with the various DMIfungicides. I could easily counton two hands (possibly even one)the number of times where a normalapplication of any of theseproducts caused significant injury. Ido not recall any situations whereobjectionable injury occurred onhigher-mowed turf, such as golfroughs, lawns or athletic fields.When using common sense, followingthe label and paying closeattention to environmental stresses,there is very little concern forserious injury from one of theseproducts. This is not to say thatserious injury to turf will neveroccur, but the likelihood is slim.Even with the newer (andtypically safer) DMI fungicides, itis probably a good idea to avoidapplying high rates to closelymowed turfgrasses when daytimeair temperatures exceed 90°F.Additionally, rotation with otherfungicide classes is recommendedfor multiple reasons.Finally, disease control withthese fungicides and others willbe optimized when the turf isfunctioning properly. Culturalpractices that alleviate stress willallow the fungicides to functionproperly as they were designed. cJournal of the Virginia Turfgrass Council | 15
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Page 10: VTF ReportNEW LEADERSHIPOPPORTUNITI
Page 13: examples of each product, however,t
Page 17 and 18: Table 1. Treatment details and that
Page 19 and 20: Cover Story continuedaerification o
Page 22 and 23: Turf TalkPerennial grassy weeds —
Page 24 and 25: continued Turf Talkproper rate has
Page 26: Applied ResearchBetter Turf fora Be
Page 29 and 30: Industry NewsGood News from TPI…E

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