Brenda Walsh, Stephanie S. Ikeda, and Greg J. Boland
Clinton J. Steketee, Alfredo D. Martinez-Espinoza, Karen R. Harris-Shultz, Gerald M. Henry, and Paul L. Raymer
.J. 1999 Biology and management of dollar spot ( Sclerotinia homoeocarpa ): An important disease of turfgrass HortScience 34 13 21
Kari L. Hugie and Eric Watkins
Turfgrass species traditionally used in residential and commercial lawns in Minnesota, such as kentucky bluegrass ( P. pratensis ) and perennial ryegrass ( L. perenne ), can require significant management inputs to maintain acceptable cover and
Yu Huang, John E. Kaminski, and Peter J. Landschoot
efficacy of chlorothalonil and propiconazole for control of dollar spot on creeping bentgrass. Online. Applied Turfgrass Science. doi: 10.1094/ATS-2008-0319-01-RS Vargas, J.M. Jr 2005 Management of turfgrass diseases. 3rd Ed. Lewis Publ., Boca Raton, FL
M. Fidanza, P. Colbaugh, H. Couch, M. Elliott, and S. Davis
Fairy ring has become a troublesome and persistent disease on golf course putting greens and other turf areas in most regions of the United States. Many basidiomycete fungi are associated with this destructive disease in turfgrass. Recent widespread epidemics of fairy ring have led investigators to examine possible management and control options. Curative approaches include topical flutolanil fungicide applications in conjunction with soil surfactants, the application of flutolanil under high-pressure injection, and the use of nitrogen fertility programs. These curative programs were effective at suppressing visual symptoms and turfgrass injury. A preventive approach evaluated repeat applications of flutolanil plus a soil surfactant prior to disease development. This preventive program was effective at eliminating visual disease symptoms on bermudagrass putting greens. Information presented will review results from field research studies conducted over the past 3 years in Florida, North Carolina, Ohio, Texas, and Virginia.
Five species and 27 cultivars of fine-leaved fescues (Festuca sp.) were evaluated for low-maintenance utility turf in a variety of golf course conditions. Cultivar selection and management techniques varied across six sites in 4 years. Germination, tillering, rapidity of establishment, turf density, and general turfgrass quality were significantly different between both species and cultivars. Annual and seasonal decline and recovery of turf quality was also dependent on both species and cultivar. Greater differences exist within cultivars in some species than between species. Aspect, slope, soil disturbance, shade, seeding date, irrigation, fertility regime, mulch, and mowing influenced establishment and seedling development. Absence of endophytic fungi and development of diseases, insects, weeds, and post-germination disturbance markedly contributed to losses in turf quality, percent living cover, and increased erosion potential. Success and duration of fescue slope plantings are both positively and negatively correlated to various site characteristics and management techniques. Fescues are an appropriate choice in specific circumstances.
Lambert B. McCarty, Leon T. Lucas, and Joseph M. DiPaola
Spring dead spot (SDS) [Gaeumannomyces graminis (Sacc.) von Arx & D. Olivier var. graminis Walker] is a serious disease of bermudagrass [Cynodon dactylon (L.) Pers.] throughout much of the southern United States and is believed to be at least partially influenced by the previous year's turfgrass management practices. Research was performed to: a) determine the efficacy of selected fungicide control measures; and b) determine the influence of N and K nutrient regimes on the expression of SDS symptoms in Tifway bermudagrass (C. dactylon x C. transvaalensis Burtt-Davy). Averaged over two sites in 2 years, a 72% reduction in SDS followed a fall application of benomyl at 12 kg·ha. Fenarimol applied at three rates (1.5, 2.3, and 3.0 kg·ha) on three fall dates reduced SDS by a combined average of 66%. A single application of propiconazole (2.5 kg·ha) reduced disease by an average of 56%. Application of N (98 kg·ha) in late fall increased SDS 128% in one test location. Application of potassium sulfate (269 kg K/ha) in late fall resulted in an average increase in SDS expression of 89% the following spring over all experiments. Turf managers with severe SDS should minimize heavy late-fall K applications and possibly use benomyl, fenarimol, or propiconazole for disease suppression. Chemical names used: α -(2-chlorophenyl)α -(4-chlorophenyl)-S-pyrimidinemethanol (fenarimol); [methyl 1(butylcarbamoyl)-2-benzimidazolecarbamate] (benomyl); 1-[[2-(2,4-dichlorophenyl)-4propyl-1,3-dioxolan-2-yl]methyl]--1H-1,2,4-triazole (propiconazole).
Chengyan Yue, Jingjing Wang, Eric Watkins, Stacy A. Bonos, Kristen C. Nelson, James A. Murphy, William A. Meyer, and Brian P. Horgan
pest resistance cluster. From the perspective of a turfgrass breeder, consumers and marketing companies had positive effects, whereas producers/growers and wholesalers had negative impact on the selection likelihood of disease and pest resistance
P.V. Blenis, L.B. Nadeau, N.R. Knowles, and G. Logue
Marasmius oreades, a causal agent of fairy rings, is one of the most important pathogens of turfgrass in the Great Plains region of North America. Following in vitro and greenhouse screening of surfactants and fungicides, two organosilicone surfactants, Silwet L-77 and Sylgard, together with the fungicide chlorothalonil, were evaluated in the field. Treatments were applied to healthy and infested turfgrass (Poa pratensis L., Festuca rubra L.) in either 1992, 1993, or in both years. Plots were sampled for grass production, canopy cover, mushroom production, grass chlorophyll content, soil water content, and phytotoxicity. Typically, there were no significant fungicide effects, fungicide by surfactant interactions or differences between Silwet L-77 and Sylgard. Relative to the water control, surfactants caused an approximate 3-fold increase in grass productivity on infested plots in the year of application. However, the difference in canopy cover between organosilicone-treated and control plots tended to be much less. Applying the surfactants to diseased plots in two successive years decreased the canopy cover but had no significant effect on grass production. Chlorophyll content tended to decrease in response to surfactants regardless of whether the turf was infested or healthy. Surfactants almost completely eliminated mushroom production and greatly reduced the occurrence of mycelium. Both organosilicones increased soil water content in infested areas; differences were detectable 2 years after application. Acute phytotoxicity from the surfactants was detected in infested but not in healthy plots. There was no direct evidence of chronic phytotoxicity. Organosilicone surfactants appear to have considerable potential for the management of fairy rings. Chemical names used: oxyalkylenemethylsiloxane (Silwet L-77); 2-(3-hydroxypropyl)-heptamethyltrisiloxane (Sylgard); tetrachloroisopthalonitrile (chlorothalonil).
D.W. Williams and P.B. Burrus
1 Assistant Professor. 2 Research Specialist. We gratefully acknowledge partial funding of this project by the United States Golf Association and the Kentucky Turfgrass Council. Discussions of herbicides and plant growth regulators imply no