Golf Course Management

FEB 2016

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104 GOLF COURSE MANAGEMENT 02.16 First report of Hemicycliophora wyei on bentgrass in Texas X. Ma and P. Agudelo, Ph.D. Creeping bentgrass (Agrostis stolonifera L.) is an important component of putting greens in the southern United States. In 2012 and 2013, soil samples from a private golf club in Dallas were received at the Clemson Univer - sity Nematology Assay Laboratory. Nema- todes were extracted from the soil by sugar centrifugal fotation and observed under the stereoscope. Sheath nematodes were found at an average density of 258 (140 to 400) in - dividuals per 6 cubic inches (100 cubic cm) of soil in 14 of 14 samples processed from symptomatic turf. No sheath nematodes were found in six samples from healthy turf. Re - ported symptoms in the turf included general decline and poor stand quality. Identifcation of the sheath nematode spe - cies was done by morphological examination of 10 females. Characteristics determining the specimens as Hemicycliop ra wyei include: cuticular sheath loosely ftting the body; lat - eral lines with breaks and anastomoses; labial disc elevated with two lip annuli; vulva with modifed lips and vulval sleeve long; tail uni - formly tapering with a conical post-vulval re- gion; body length = 1,001 µm (945 to 1,153 µm); and tail length = 107.7 µm (100 to 112 µm). No males were observed. This species was recently described from specimens associ - ated with turfgrass in North Carolina, but no pathogenicity studies are available. Molecu - lar diagnosis was confrmed using sequences from two ribosomal DNA markers from fve individuals. The sequences obtained from amplifcation were submitted to the Gen - Bank database and assigned accession number KC329574 for D2-D3 of the 28S gene, and KC329575 for the ITS1-5.8S-ITS2 region. These sequences were the frst submitted for this species. At the time of submission, the closest match was H. lutosa (93% identity). Additional sequences for H. wyei were later submitted by other scientists, and these se - quences were 99% identical to ours. Host suitability was tested in the green - house by growing the same varieties of bent- grass (blend of 70% Tyee and 30% 007) in 6-inch-diameter (15-cm) plastic pots flled with sandy soil that meets USGA recommen - dations for greens. The soil was inoculated with 250 sheath individuals per 6 cubic inches (100 cubic cm) of soil. Six months after in - oculation, fnal populations were 950 (430 to 1,640) individuals per 6 cubic inches of soil, confrming bentgrass is a suitable host for H. wyei. To date, this nematode has been reported only in North Carolina on an un - specifed turfgrass species, and in Florida on Andropogon virginicus (broomsedge bluestem). Awareness of the host status of this newly de - scribed species, which is potentially harmful to bentgrass, is relevant to the maintenance of golf course turf. To our knowledge, this is the frst report of H. wyei in Texas, and the frst report of this species on bentgrass. Source: Plant Disease, May 2015, 99(5):732 Xinyuan Ma is a graduate research assistant and Paula Agudelo is an associate professor in the Department of Agricultural and Environmental Sciences at Clemson Uni - versity, Clemson, S.C. rotia collected from each feld after harvest ranged from 4 to 15 sclerotia per 10.7 square feet (1 square meter) in 2012 and from 18 to 119 sclerotia per 10.7 square feet in 2013. Scle - rotia left in perennial felds after harvest are a signifcant source of inoculum that should be targeted for control. This is the frst study to quantify spatial patterns of ergot in perennial ryegrass, and it provides insight into possible mechanisms that contribute to ergot etiology and epidemiology. Accepted for publication in Plant Disease Jeremiah K. S. Dung ( is an assistant professor based at Oregon State Univer - sity's Central Oregon Agricultural Research Center in (report) Madras, Ore.; Stephen Alderman is a research plant pathologist at the USDA-ARS National Forage Seed Pro - duction Research Center, Corvallis, Ore.; Darrin L. Walenta is an assistant professor at Oregon State University in LaGrande, Ore., and an Extension agronomist for three counties in the state; Philip B. Hamm is professor emeri - tus, plant pathologist and station director at Oregon State University's Hermiston Agricultural Research & Extension Center in Hermiston, Ore. The sheath nematode species found in a creeping bentgrass putting green in Dallas was identifed as Hemi - cycliophora wyei. Photos by Xinyuan Ma

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