Turf Line News

June/July 2014

Issue link: http://read.dmtmag.com/i/319149

Contents of this Issue

Navigation

Page 23 of 47

24 WESTERN CANADA TURFGRASS ASSOCIATION RESEARCH UPDATE BY CLINT MATTOX, ALEC KOWALEWSKI, AND BRIAN MCDONALD, DEPARTMENT OF HORTICULTURE, OREGON STATE UNIVERSITY EFFECTS OF ALTERNATIVES TO TRADITIONAL FUNGICIDES AND WINTER FERTILIZATION PRACTICES ON MICRODOCHIUM PATCH IMAGE 1: Graduate assistant, Clint Mattox, applies a series of fungicide alternative products exploring pesticide-free control of Microdochium patch at the OSU Lewis Brown farm in Corvallis, OR, September 26, 2013. IMAGE 2: Effects of Sulfur DF (0.25 lbs/1,000 ft2; 12.21 kg/ha) and Civitas One (8.5 oz/1,000 ft2; 27.06 L/ha), applied every two weeks (above) in comparison to the control (below) observed November 20, 2013 (applications initiated September 26, 2013). INTRODUCTION: Microdochium patch can be observed year-round in some cool, humid regions, and damages nearly all grass species in Western Canada and the Pacific Northwest. Microdochium patch is a major disease on golf course putting greens from September through May, and under favorable condi- tions, can injure or kill significant amounts of turf which greatly disrupts the aesthetics and playability of the putting green surface. Historically, more money has been spent on fungicides to combat this disease in Western Canada and the Pacific Northwest than any other turfgrass disease. Currently, fungicides applied every three to four weeks to putting greens throughout the 9 month period of disease activity are the primary means for pro- viding control of this pathogen, which equates to roughly $20,000 annually per golf course. In recent years, increasing pesticide bans and restrictions have limited the options for managing pest problems including diseases like Microdochium patch. Considering this, little information exists regarding alterna- tive integrated management strategies that might significantly reduce or eliminate the need for fungicide applications. The overall objective of this research theme is the explo- ration of fungicide alternative management of Microdochium patch on annual bluegrass putting greens. RESEARCH UPDATE (SEPTEMBER 26, 2013 TO MARCH 01, 2014): In continued exploration of fungicide alter- native products and practices for management of Microdochium patch a series of experiments were initiated at the Oregon State University Lewis Brown Horticulture Farm and at the Wash- ington State University Goss Research Farm, Puyallup, WA on September 26, 2013 (Image 1). Alternatives to Traditional Fungicides (Table 1 and Image 2): The objective of this study was to evaluate the efficacy of alternatives to traditional fungi- cides for the control of Microdochium patch on an annual bluegrass putting green. Fungicide alternative treatments applied every other week since September 26, 2014 included Sulfur DF (0.25 lbs/1,000 ft2; 12.21 kg/ha), Civitas One (8.5 oz/1,000 ft2; 27.06 L/ha), PK plus L (6.0 oz/1,000 ft2; 19.10 L/ha), as well as all possible combinations of these products, in comparison to an untreated check plot (Table 1). Rolling was also investigated as a cultural practice to reduce disease in combination with the fungicide alter- native treatments. The untreated check plots averaged 45.0 per- cent disease cover on rating date, Mar 1, 2014 (Table 1). When Civitas One was mixed with any of the fertilizer combinations (Sulfur, PK plus, or Sulfur and PK plus) 0.5 percent disease or less was observed (Image 2). Civitas One, Sulfur and PK plus alone were able to provide some disease control, but none were able to provide acceptable control for putting green quality. In March, rolling reduced disease severity only when the products discussed above were not applied. When these products were applied, rolling had little effect on disease severity, or turf color and quality. Roll- ing in combination with all plots where Civitas One was applied began to show signs of abiotic damage on 09 Jan 2014. The manufacturers of Civitas One recommend only applying it when the turf is actively growing. This suggests that the decreasing temperatures in combination with rolling led to a decline in turf quality. Winter Fertilization Practices (Table 2 and Image 3): The objective of this study was to evaluate the efficacy of winter fertility practices in combina- tion with simulated traffic in order to determine their effects on the suppression of Microdochium patch and turfgrass recovery on annual blue- grass in western Oregon, 2013-2014. Treatments applied in this study every other week begin- ning September 26, 2014 included iron sulfate applied at 0.0, 0.25, 0.5, 1.0 and 2.0 lbs/1,000 ft2 (0.0, 12.21, 24.41, 48.82 and 97.65 kg/ha) and nitrogen (46-0-0) applied at 0.0, 0.1 and 0.2 lbs N/1,000 ft2 (0.0, 4.88 and 9.76 kg/ha) as well as all possible combinations of these iron sul- fate and nitrogen rates (Table 2). All treatments IMAGE 3 (right): Effects of iron sulfate, applied at 2.0 lbs FeSO4/1,000 ft2 (97.65 kg FeSO4/ha) every two weeks (left), and nitrogen (46-0-0), applied at 0.1 lbs N/1,000 ft2 (4.88 kg N/ha), plus iron sulfate, at 2.0 lbs FeSO4 per 1,000 ft2 (97.65 kg FeSO4/ha) every two weeks (right) on Microdochium patch incidence and annual bluegrass putting green health, picture collected Jan 10, 2014 (four months after the fall 2013 initiation date). Note: the poor quality associated with the plot on the left is the result of foot traffic, which is applied to all treatments in the study. Continued on Page 26 ALL IMAGES AND TABLES COURTESY OREGON STATE UNIVERSITY

Articles in this issue

Archives of this issue

view archives of Turf Line News - June/July 2014