Golf Course Management

FEB 2015

Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.

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02.15 GOLF COURSE MANAGEMENT 131 First report of Meloidogyne marylandi infecting bermudagrass in Oklahoma Nathan Walker, Ph.D. Meloidogyne marylandi is a nematode commonly associated with turfgrasses and has been reported to occur in Texas and Ar - kansas. In fall 2013, a stand of ultradwarf bermudagrass (Cynodon dactylon × C. trans - vaalensis) plants in a sand-based, research putting green in Stillwater, Okla., exhibited symptoms of decline. Roots of the affected plants had small galls and, upon staining of the root system, numerous egg masses were evident. Egg masses were collected and placed in water, and the morphology of 20 hatched, second-stage juveniles were examined. The characteristics of the juveniles were: body length averaged 393.1 ± 19.87 (range: 361- 425) micrometers, mean width averaged 16.6 ± 0.7 ( a range of 15.6-17.8) micrometers, sty - let lengths averaged 12.1 ± 0.7 (10.4-12.9) micrometers, dorsal gland orifce from stylet base averaged 2.9 ± 0.4 (2.5-3.6) microm - eters, tail lengths averaged 53.7 ± 3.8 (46.2- 60.4) micrometers, and the hyaline region of the tails averaged 10.4 ± 1.1 (8.4-12.7) micrometers. Six females were removed from roots, and their genomic DNA was extracted, amplifed and sequenced. Genetic testing showed that the sequences exhibited 97% identity with two sequences from M. mary - landi (KC473862.1 and KC473863.1); the next most similar species was M. graminis (JN241898.1) with 83% identity. To our knowledge, this is the frst report of the root-knot nematode M. marylandi in Oklahoma. As bermudagrass becomes more commonly used for putting greens in the turf - grass transition zone, M. marylandi may be- come a more common and damaging patho- gen in the region. Source: Plant Disease, September 2014, 98(9):1286. http://dx.doi.org/10.1094/PDIS-04-14-0399-PDN Nathan Walker, Ph.D. (nathan.walker@okstate.edu), is a professor in the department of entomology and plant pathology, Oklahoma State University, Stillwater, Okla. diameter agar plugs, colonized by mycelia of each S. omoeocarpa isolate, onto two of the plants' leaves. Two plants were inoculated with each isolate and sterile agar plugs were placed on two leaves of another seedling as control. Plants were incubated in a dew cham - ber at 68 F (20 C) and a 12-hour photoperiod. After three days of incubation, water-soaked lesions surrounded by a dark margin appeared on inoculated plants only. Fungi that were later identifed as S o - moeocarpa isolates SLC2 and SLC3 by se- quencing of the ITS region were re-isolated from symptomatic leaves, fulflling Koch's postulates. To our knowledge, this is the frst report of dollar spot on sandbur. Source: Plant Disease, August 2014, 98(8):1160 http://dx.doi.org/10.1094/PDIS-03-14-0244-PDN Francisco Flores was a graduate student at the time of this discovery and has since received his Ph.D. from Okla - homa State University, and Nathan Walker, Ph.D. (nathan. walker@okstate.edu), is a professor in the department of entomology and plant pathology, Oklahoma State Univer - sity, Stillwater, Okla. (Report) The nematode Meloidogyne marylandi was discovered in fall 2013 in a stand of ultra- dwarf bermudagrass plants in a sand-based research putting green in Stillwater, Okla. Photos by Nathan Walker

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