Research was conducted to evaluate crabgrass [Digitaria ischaemum (Schreb.) Muhl.] control, incidental dollar spot (incited by Lanzia and Moellerodiscus spp.) suppression, and turfgrass quality following sequential, low-level postemergence applications of DSMA to creeping bentgrass (Agrostis stolonifera var. palustris Farwell). DSMA was applied at 22 mg·m-2 at 7-day intervals for 15 consecutive weeks (DSMA-W) from May through Aug. 1986 and 1987 and for 10 consecutive weeks from June through Aug. 1988. DSMA also was applied in three split applications of 110 mg·m-2 every 10 days (DSMA-S) in June and July of each year. DCPA was applied in a single, preemergence application in May as a comparative standard for crabgrass control. Percent crabgrass in either DSMA-treated plot was 20% by 11 Sept., an infestation that was unacceptable for high-quality turf. Percent crabgrass infestation was 6% at all rating dates in 1987 or 1988 for DSMA-W and 11% at all dates in 1987 or 1988 for DSMA-S. DCPA significantly reduced percent crabgrass as compared to the nontreated control at all rating dates, but the percent crabgrass ratings tended to be higher than those for either DSMA treatment by the final rating dates of each year. The DSMA treatments significantly reduced dollar spot incidence in each year. Turfgrass discoloration was observed following the DSMA-S treatment in July 1987 as compared to the control, but the turf quality recovered by August. Turfgrass quality was higher for DSMA treatments than for either DCPA or the nontreated control due to season-long crabgrass control and disease suppression. Chemical names used: disodium methanearsonate (DSMA), dimethyl tetrachloroterephthalate (DCPA).
J.M. Goatley Jr. and R.E. Schmidt
Thomas O. Green, John N. Rogers III, James R. Crum, Joseph M. Vargas Jr., and Thomas A. Nikolai
Turfgrass health is a major concern for golf course managers. Dollar spot ( Salgado-Salazar et al., 2018 ; Smiley et al., 1992 ) is the most common foliar disease in the upper Midwest affecting turfgrass quality and playability resulting in the
John E. Kaminski and Michael A. Fidanza
Dollar spot ( Sclerotinia homoeocarpa F.T. Bennett) is perhaps the most chronic and problematic disease of golf course turf throughout the United States ( Couch, 1995 ; Dernoeden, 2000 ). The disease can be particularly damaging to creeping
Yu Huang, John E. Kaminski, and Peter J. Landschoot
Dollar spot, caused by Sclerotinia homoeocarpa F.T. Bennett, is considered the most economically important disease of golf course turf in the northern United States ( Vargas, 2005 ). Leaf wetness in the form of dew (condensate and plant
Christopher P. Ryan, Peter H. Dernoeden, and Arvydas P. Grybauskas
Dollar spot ( Sclerotinia homoeocarpa ) is a major disease of turfgrasses that is problematic for golf course superintendents throughout most of the United States. Creeping bentgrass ( Agrostis stolonifera ) is a commonly grown turfgrass species on
Clinton J. Steketee, Alfredo D. Martinez-Espinoza, Karen R. Harris-Shultz, Gerald M. Henry, and Paul L. Raymer
( Chapman and Peat, 1992 ). Several biotic stresses affect seashore paspalum including nematodes, insects, and pathogens. In particular, plant diseases can be a major problem for turfgrass practitioners managing seashore paspalum. Dollar spot, caused by S
Jose A. Oliveira, Ana B. Monteagudo, Suleiman S. Bughrara, Jose L. Martínez, Ana Salas, Esther Novo-Uzal, and Federico Pomar
relationships in 34 Iranian fescue accessions. The fungus Sclerotinia homoeocarpa F.T. Bennett causes dollar spot, a leaf disease of closely mowed turf throughout the world ( Bonos et al., 2003 ). Symptoms appear as bleached spots approximately the size of a
A field study was conducted to evaluate the effect of tall fescue (Festuca arundinacea Schreb.) cultivar, seeding rate, N fertilization rate, and cutting height on the severity of dollar spot (Lanzia and Moellerodiscus spp.) disease incidence. All possible two-factor interactions among these four management factors were statistically significant when averaged over the 2 years of study. Disease severity tended to be lowest at low fescue seeding rate (2100 pure-live seeds/m*) at the lower (19 mm) height of cut. `Mustang', the turf-type cultivar with improved density, was more susceptible to dollar spot than `Kentucky-31', the common-type cultivar.
Glenn A. Hardebeck, Ronald F. Turco, Richard Latin, and Zachary J. Reicher
Pseudomonas aureofaciens strain Tx-1 is suggested as a biological control for Sclerotinia homoeocarpa (F.T. Bennett) and brown patch (Rhizoctonia solani Kuhn) on golf courses. To overcome application difficulties, a field bioreactor is used to grow Tx-1 daily and then inject into nightly irrigation on the golf course. Though Tx-1 shows some promise for disease control in vitro, it is relatively untested under field conditions. We conducted three field experiments to 1) evaluate the efficacy Tx-1 when applied through an irrigation system for the control of dollar spot and brown patch; 2) determine if there is an interaction between nitrogen fertility or fungicides on efficacy of Tx-1; and 3) determine if Tx-1 can extend the duration of dollar spot control by a single application of fungicide. Nightly applications of Tx-1 through irrigation did not affect brown patch on `Astoria' colonial bentgrass (Agrostis capillaris Sibth.) during the 2 years of our study. Tx-1 reduced dollar spot in `Crenshaw' creeping bentgrass (Agrostis palustris Huds.) by 37% in 1998 compared to non-Tx-1 treatments, but Tx-1 had no effect on dollar spot in 1999. Under low disease pressure, Tx-1 increased the dollar spot control of fungicides by 32% and increased the duration of control by 2.6 days. However, Tx-1 had no effect on fungicide efficacy or duration of control later in the summer when dollar spot pressure was high. Fungicides did not negatively affect Tx-1's control of brown patch or dollar spot, nor did fertilizer regime affect brown patch or dollar spot control by Tx-1. Although delivery of Tx-1 in our studies was optimized, disease control was marginal and occurred only under low disease pressure. Therefore, we conclude Tx-1 has limited practical value for turfgrass disease control on golf courses.
Joon Lee, Jack Fry, and Ned Tisserat
There is interest in identifying cultural practices that may reduce fungicide requirements of creeping bentgrass (Agrostis palustris Huds.) putting greens. Our objective was to evaluate the plant defense activator ASM in combination with 12 biostimulants for the potential to reduce dollar spot (Sclerotinia homoeocarpa F.T. Bennett) and brown patch (Rhizoctonia solani Kuhn) in a blend of `Cato: `Crenshaw creeping bentgrass during 2000 and 2001. The experimental design was a split-plot with ASM as the whole plot, and biostimulants as the subplots. ASM was applied biweekly as a.i. at 35 g·ha-1 and biostimulants were applied according to manufacturers recommendations. Sclerotinia homoeocarpa infection centers were reduced by 38% with ASM, but levels were >1500/m2 in Aug. 2000, and turf quality was unacceptable through most of the study period. No suppression of brown patch occurred with ASM. None of the biostimulants reduced dollar spot or brown patch in creeping bentgrass when compared to biweekly applications of soluble N at 4.9 kg·ha-1. Dollar spot suppression achieved with ASM warrants additional studies to determine how it might be used to reduce fungicide inputs on creeping bentgrass putting greens. Chemical name used: acibenzolar-S-methyl (ASM).