Golfdom, February 2015

research for real superintendents Hosted by Clark Trossell Ph D clarkthrossell@ bresnan net Super Science on the green NitrogeN fertility mowiNg height aNd topdressiNg effects oN aNthracNose By James Hempfling A nthracnose on annual bluegrass Poa annua greens caused by Colletotrichum cereale Manns can be suppressed by increasing nitrogen fertility mowing height and sand topdressing Efects of these practices on disease severity and ball roll remain unknown A 3 year feld trial was initiated in 2012 in North Brunswick N J to evaluate the efects Treatments were all combinations of mowing height 009 and 0125 inch N fertility 205 and 41 lbs N 1000 f2 year and sand topdressing 950 and 2000 lbs sand 1000 f2 year during 2012 750 and 1650 lbs sand 1000 f2 year during 2013 and 2014 Trinexapac ethyl was applied weekly at 0125 oz 1000 f2 and lightweight vibratory rolling was performed three times week As expected increased N fertility mowing height and sand topdressing reduced disease severity reported as the area under the disease progress curve AUDPC N fertility accounted for the majority of the variation in AUDPC and mowing height accounted for a slightly greater amount than sand topdressing Interestingly more frequent sand topdressing produced greater disease suppression when turf was maintained under low nitrogen and low mowing compared to high in 2012 and 2014 Recovery from disease damage was enhanced by higher mowing increased N fertility and more frequent topdressing Recovery was substantially hindered by low mowing under infrequent topdressing In regard to ball roll distance the relative importance of management factors difered from that observed with AUDPC responses Increased mowing height caused a substantial reduction in ball roll distance greater N fertility and sand topdressing had minimal efects on ball roll distance Tese fndings suggest that priority should be given to lowering mowing height rather than reducing N fertility or sand topdressing rates to increase ball roll distance without greatly increasing the risk for anthracnose James Hempfling graduate research assistant Bruce Clarke Ph D extension specialist in turfgrass pathology and James Murphy Ph D extension specialist in turfgrass management are at Rutgers University For more information contact Hempfling at james hempfling@ rutgers edu news updates in memory of james andrew mcafee PH d James andrew Mcafee born Jan 22 1945 in edinburg texas passed away Jan 31 2015 in richardson texas after a lengthy battle with pulmonary fbrosis he is survived by his wife of 47 years Kayla Mcafee and their three sons two daughtersin law and four grandsons Mcafee received his bachelors and Masters degrees from texas a M university and his ph d from purdue university specializing in turfgrass sciences in 2013 after 40 years in the turfgrass industry Mcafee retired as an associate professor and turfgrass specialist with the texas agrilife extension in dallas his numerous professional organization affliations include the texas turfgrass association and sports turf Managers association his infuence in the turfgrass feld includes in depth research on reducing inputs of fertilizer pesticides and water the family has created and asked for donations to the Mcafee Memorial scholarship at texas a M university the funds will go toward a student pursuing a career in sports turf management to make a contribution visit www txstma org dr jamesmcafee scholarship donations html February 2015 Golfdom 45 Golfdom com photo by youssef elkhateeb properly timiNg the adulticide applicatioN has beeN the biggest hurdle iN aNNual bluegrass weevil coNtrol giveN that abw adulticides have short residual activity Ben McGraw Ph D see full story on page 46 a measuring tape is placed along plots to measure ball roll distance on annual bluegrass putting green turf receiving different levels of nitrogen fertility mowing height and sand topdressing