Issue link: https://read.dmtmag.com/i/96024
TL1301-proof 11/22/12 9:19 AM Page 1 Bluegrass Cont'd From Page 17 The purified PCR products were sequenced and a BLAST search exhibited seven isolates with 99% and 100% similarity to M. poae in the GenBank database. As well, pathogenicity of four isolates was confirmed using Koch's postulates. Healthy P. annua samples (core-sized) collected from an Ontario golf course were inoculated with M. poae-infested grass seed and were placed in a growth chamber at 25-30oC. After approximately 3 weeks, inoculated plants appeared symptomatic (chlorotic foliage; dark runner hyphae on roots). Infected roots were sterilized and placed on antibiotic medium; fungal cultures exhibited the same morphology and characteristics as those previously identified as M. poae. Field Trials A field study was conducted during the 2010 season at the Guelph Turfgrass Institute (GTI) on the Poa annua green established for this project. The randomized trial consisted of several treatments including a variety of fungicide application regimes and untreated controls. Four replicates each of preventative application of azoxystrobin (watered-in and not watered-in) and curative application of azoxystrobin (watered-in and not watered-in) were performed. Various control treatments (no inoculum + no azoxystrobin controls and inoculum + no azoxystrobin) were used. Photographs (Figure 2), disease severity ratings, turf quality ratings and visual observation of the roots using core samples were taken during the trial to assess treatments. As well, cup cutter samples were taken from each plot at the end of the trial. Data analysis using the disease severity ratings and turf quality ratings was completed. It appears that preventative watered-in application of azoxystrobin is the most effective for pathogen and disease management. Figure 2. Results of 2010 field trial. a) no fungicide applied, b) azoxystrobin applied, not watered in c) azoxystrobin applied, watered in. The azoxystrobin trial was re-established in summer 2012, along with newly developed trials examining various nitrogen-based fertilizers (ammonium sulfate, ammonium nitrate and urea) as well as a trial with a combination of cultural management practices (no management, foliar and soil manganese sulfate, azoxystrobin, propiconazole, thiophanate-methyl watered-in, water acidification, azoxystrobin + water acidification, azoxystrobin + managanese sulfate, managanese sulfate + water acidification). Data collection and statistical analysis is currently underway for the 2012 trials. M. poae mating and determination of pathogenicity: The seven isolates that were positively identified as M. poae were mated with each other and with the M. poae ATCC cultures to determine incompatibility and compatibility between fungi (See photos on first page of article). Forty-eight containers (Poa from GTI green) were established and maintained in greenhouse for 3 weeks (allowed roots to grow; maintained at greens height). Prepared inoculum with ATCC cultures and positive M. poae cultures. Arranged in randomized complete block design, 4 replicates (Figure 4). Applied inoculum at soil level and on foliage. After inoculation, containers transferred to growth chamber with 12-h day/night cycles at 30/25oC. Containers were trimmed to greens height (~ 3 mm) once every week. Disease severity was assessed 4 weeks after inoculation using a scale of 0 to 10 corresponding to the percentage of foliar tissue exhibiting chlorosis/dieback: • 10 --> 100% chlorosis • 5 --> 50% chlorosis • 0--> 0% chlorosis After evaluation, containers were Currently, summer patch disease is managed primarily through preventative chemical applications in conjunction with cultural practices. monitored and evaluated once per week, containers were photographed once per week. Data analysis is currently ongoing. The growth chamber experiment will be repeated again in 2012/2013/ Fall 2012 The plans for the fall of 2012 are to conduct statistical analyses of data collected from 2012 field trials, collect fresh Poa annua ecotypes and inoculate P. annua ecotypes for further pathogenicity testing, conduct M. poae mating (on wheat; for production of perithecia). References: Clarke, B.B., Thompson, D., Murphy, J., and Majumdar, P. 1995. Development of an integrated summer patch control program for fine turf areas. Proceedings of the Fourth Annual Rutgers Turfgrass Symposium. pp. 18-19. Smiley R.W., Dernoeden, P.H., and Clarke, B.B. 2005. Compendium of turfgrass diseases, 3rd Ed. Vincelli, P. and Williams, D.W. 2011. Chemical control of turfgrass diseases. University of Kentucky Cooperative Extension Service. WESTERN CANADA TURFGRASS ASSOCIATION BOARD OF DIRECTORS 2012-2013 TITLE NAME PRESIDENT: Tab Buckner VICE PRESIDENT: Keith Lyall 2 - YEAR DIRECTORS: Jeff Bennett Larry Olson Trevor Smith Peter Sorokovsky Dr. Brian Holl ORGANIZATION PHONE FAX Township of Langley Sun Peaks Resort (604) 532- 3504 (250) 578-5535 (604) 532-7310 (250) 578-5435 tbuckner@tol.ca klyall@sunpeaksresort.com (250) 861-9480 (250) 492-2819 (250) 320-6411 (604) 297-4494 (250) 492-2819 (604) 940-2244 (604) 297-4492 jcbenny@shaw.ca super@pentictongolf.ca trevoralfa@shaw.ca peter.sorokovsky@burnaby.ca (250) 370-9308 (250) 370-9308 fbholl@hotmail.com (403) 660-0160 (250) 714-4685 (403) 777-7145 (250) 323-7072 (250) 743-1228 (403) 556-8243 (604) 614-7875 (604) 869-9282 (250) 743-5518 (403) 507-7797 (604) 856-7972 1-866-366-5097 Penticton Golf & CC Keso Turf Supplies City of Burnaby, Parks, Rec, & Cultural Serv. Lamorna Enterprises PORTFOLIOS E-MAIL 1 - YEAR DIRECTORS: Mike Schellenberg Calgary Board of Education Brett Lamontagne Mid-Island Landscape Consulting Inc. Brett Finlayson Arbutus Ridge Golf Club Jason Pick Olds College PAST PRESIDENT: Scott Mitchell Target Products EXECUTIVE DIRECTOR: Jerry Rousseau EXECUTIVE ASSISTANT: Leslie Carnell Constitution Review mjschellenberg@cbe.ab.ca tangoturf@shaw.ca bfinlayson@golfbc.com jpick@oldscollege.ca smitchell@targetproducts.com exec.director@wctaturf.com admin@wctaturf.com WESTERN CANADA TURFGRASS ASSOCIATION 19