Virginia Turfgrass Council / PO Box 5989 / Virginia Beach, VA 23471 ...

Cover StoryBy David McCall, Research Specialist, Dept. of Plant Pathology, Virginia TechForyears, weseemedto knoweverything there was to knowabout ergosterol biosynthesisinhibitors, or more commonlyknown as demethylation inhibitors(DMIs). Propiconazole (Banner),triadimefon (Bayleton) andmyclobutanil (Eagle) were staplesof most turf managers’ fungicidearsenal. Fenerimol (Rubigan)certainly had its place in themarket, and people were relativelycomfortable with its uses andlimitations. Turf managers hadused these products repeatedlyover the years, and they knewwhat to expect. Not much reallychanged for well over a decade.Over the last three years, however,the turf market has seen thelaunch of three new active ingredientsin this class: metconazole(Tourney), tebuconazole (Torque,Quali Pro Tebuconazole) andtriticonazole (Trinity and Triton).Along with a new set of productscomes a new set of questions.Will disease control be the same?Will growth regulation still occur?Can these products be used inrotation with the older DMIs?Can plant growth regulators stillbe applied in conjunction withthese products?While all of these DMIs havesome similarities, each producthas unique advantages and disadvantages.For instance, most of thenewer DMIs have increased activityagainst anthracnose and brownpatch, compared with some of theolder chemistries, but they oftenlag behind in controlling dollarspot. As with the older generationof DMIs, the newest additionspose some potential for someturf injury. Injury and/or growthregulation is most frequentlyobserved on golf course puttinggreens, but it is seldom a problemon higher-cut turfgrasses.Generally speaking, the newgeneration is considered to besafer, with reduced risk of anyobjectionable injury. I have seen12| VIRGINIA TURFGRASS JOURNAL January/February 2012 www.vaturf.org