Turfgrass Disease Trends in California and the Western United States Naveen Hyder & Frank Wong Department of Plant Pathology & Microbiology University of California, Riverside

Background information California has the largest turf and landscape industry in the US (approx. 15 billion) Approx. 950 golf courses in the state of California – 2nd in the US Not much information available due to lack of turfgrass pathology program since the1990s 1997 survey green industry worth 6 billion 15 billion/golf 7 billion First attempt to quantify data

Objective What are the major disease problems? To assess turfgrass disease trends in California and the Western United States based on diagnostic laboratory data What are the major disease problems? What are the major hosts? What are the disease trends over the last four years? Where should research efforts be focused?

Materials and methods A sample = 1 cup cutter size plug of plants and soil For this study 1 data point = one pathogen/plant interaction Data based on diagnostic samples received Samples are not evenly distributed throughout the Western United States Multiple samples from the same location Data collected from 2006-2009 (present)

Collecting a data point Microscopic signs >>> incubate up to 24-48 hrs Isolation from tissue Leaves, roots and crown on pathogen specific media Samples delivered overnight

Turf Management for Golf Courses 2001 J. Beard Large area encompassing several climate zones Turf Management for Golf Courses 2001 J. Beard

Common turfgrass species used in California and the Western U.S. Cool Season (C3 Photosynthesis) Poa annua Poa trivialis Agrostis stolonifera Festuca arundinacea Festuca rubra Lolium perenne Warm Season (C4 Photosynthesis) Cynodon spp. Pennisetum clandestinum Paspalum vaginatum Stenotaphrum secundatum 65 to 75°F Summer dormant 80 to 95°F Winter dormant bermudagrass – common and hybrid

Geographic origin (based on # of samples received) 2006 2007 2008 2009 Arizona 7 2 1 13 California 389 (85%) 366 (80%) 235 (77%) 402 (79%) Colorado 3 11 Hawaii 4 6 5 Idaho Nevada 23 (5%) 40 (9%) 28 (9%) 25 (5%) Oregon 14 9 Texas Utah Washington 20 (4%) 17 (4%) 12 (4%) 31 (6%) n = 460 n = 457 n = 306 n = 512

Sources of samples (based on number of samples received) 2006 2007 2008 2009 Residential/ commercial landscape 8 7 15 Sports turf 11 18 Golf courses 438 (95%) 439 (96%) 283 (92%) 477 (93%) Sod farms 3 - 1 2 n = 460 n = 457 n = 306 n = 512

Most common turfgrass hosts Data based on n= 3,360 diagnosis

Poa annua (Annual bluegrass) diseases trends Top 5 from 2006 to 2009 2006 (442) * 2007 (425) * 2008 (471) * 2009 (358) * Algae (17%) Rapid Blight (11%) Anthracnose (14% ) Anthracnose (18%) Summer Patch (15%) Anthracnose (11%) Rapid Blight (13%) Rapid Blight (8%) Rapid Blight (9%) Summer Patch (9%) Algae (12%) Algae (8%) Brown Ring Patch (9%) Summer Patch (8%) Anthracnose (8%) Algae (6%) Brown Ring Patch (5%) Michrodochium Patch (6%) * Total annual bluegrass samples processed Algae (Cyanobacteria) = Oscillatoria spp. Anthracnose = Colletotrichum cereale Brown Ring Patch = Waitea circinata var. circinata Rapid Blight = Labyrinthula terrestris Summer Patch = Magnaporthe poae Michrodochium Patch = Michrodochium nivale

Agrostis stolonifera (Creeping bentgrass) disease trends Top 5 from 2006-2009 2006 (263) * 2007 (201) * 2008 (185) * 2009 (187) * Algae (24%) Take-All Patch (23%) Algae (10%) Anthracnose (18%) Take-All Patch (21%) Take-All Patch (10%) Take-All Patch (14%) Fairy Ring (5%) Anthracnose (6%) Algae (11%) Anthracnose (5%) Fairy Ring (4%) Pythium Blight (5%) Fairy Ring (6%) Pythium Blight (3%) Rhizoctonia Brown Patch (4%) Rhizoctonia Brown Patch (5%) * Total creeping bentgrass samples processed Algae (Cynobacteria) = Oscillatoria spp. Anthracnose = Colletotrichum cereale Fairy Ring = Various Basidiomycete spp. Pythium Blight = Pythium spp. Rhizoctonia Brown Patch = Rhizoctonia solani Take-All Patch = Gaeumannomyces graminis var. avenae

Lolium perenne (Ryegrass) disease trends Top 3 from 2006 - 2009 2006 (173)* 2007 (106)* 2008 (61)* 2009 (67)* Bipolaris Leaf Spot (15%) Brown Patch (21%) Brown Patch (18%) Anthracnose (39%) Brown Patch (15%) Curvularia Blight (17%) Anthracnose (16%) Curvularia Blight (14%) Summer Patch (7%) Bipolaris Leaf Spot (9%) *Total ryegrass samples processed Anthracnose = Colletotrichum cereale Bipolaris Leaf Spot = Bipolaris spp. Brown Patch = Rhizoctonia solani Curvularia Blight = Curvularia spp. Summer Patch = Magnaporthe poae

Cynodon spp. (bermudagrass) disease trends Top 3 from 2006 - 2009 2006 (65)* 2007 (21)* 2008 (45)* 2009 (79)* Spring Dead Spot (23%) Rhizoctonia Large Patch (38%) Bermudagrass Decline (29%) Bermudagrass Decline (35%) Bipolaris Leaf Spot (22%) Spring Dead Spot (28%) Spring Dead Spot (18%) Spring Dead Spot (10%) Bermudagrass Decline (17%) Bipolaris Leaf Spot (14%) Bipolaris Leaf Spot (10%) * Total Bermudagrass samples processed Spring Dead Spot = Ophiosphaerella narmari / O. korrae Bipolaris Leaf Spot = Bipolaris spp. Bermudagrass Decline = Gaeumannomyces graminis var. graminis Rhizoctonia Large Patch = Rhizoctonia solani

Pennisetum clandestinum (kikuyugrass) disease trends Top 3 from 2006 - 2009 2006 (28)* 2007 (18)* 2008 (23)* 2009 (14)* Gray Leaf Spot (38%) Kikuyugrass Decline (38%) Kikuyugrass Decline (44%) Rhizoctonia Large Patch (43%) Kikuyugrass Decline (21%) Gray Leaf Spot (16%) Rhizoctonia Large Patch (22%) Kikuyugrass Decline (36%) Rhizoctonia Large Patch (18%) Rhizoctonia Large Patch (16%) Gray Leaf Spot (13%) *Total Kikuyugrass samples processed Gray Leaf Spot = Pyricularia grisea Kikuyugrass Decline = Gaeumannomyces graminis var. graminis Rhizoctonia Large Patch = Rhizoctonia solani AG 2-2

Summary Total # of samples received (2006-2009) = 3,360 94 % of the samples received are from golf courses 90% of these samples from golf course greens Cool season grasses comprise 85% of the samples 50% of these samples are annual bluegrass # 1 problem on annual bluegrass is Anthracnose

Conclusions First effort to summarize data pertaining to turfgrass diseases in the Western United States California has a unique turfgrass disease profile because of diversity of climate zones within the state Top research priority should be cool season turf management esp. diseases of annual bluegrass Find replacement for poa or find better ways of managing

Future research scope Use the data base to: Compare and contrast information with other regions Correlate disease trends with climatic variations Correlate disease trends with agronomic practices specific to California

Acknowledgements GCSAA Environmental Institute of Golf California State GCSAs Syngenta Professional Products Bayer Environmental Sciences