Issue link: http://read.dmtmag.com/i/319149
26 WESTERN CANADA TURFGRASS ASSOCIATION then received weekly foot traffic at a rate equivalent to Trysting Tree Golf Course in Corvallis, OR. As of March 1, 2014, the untreated control plots averaged the highest dis- ease severity, 55%. Plots that received iron sulfate at 2.0 lbs/1,000 ft2 (97.65 hg/ha) with nitrogen applied at the 0.1 lbs N/1,000 ft2 (4.88 kg/ha) rate and without nitrogen had the lowest per- cent of disease (Table 2 and Image 3). When iron sulfate was applied at 2.0 lbs/1,000 ft2 (97.65 kg/ha) in combina- tion with nitrogen at the 0.2 lbs N/1,000 ft2 (9.76 kg/ha) rate disease pressure increased. While iron sulfate applied at 2.0 lbs/1,000 ft2 (97.65 kg/ha) without nitrogen provided some of the lowest disease percentage it also produced some of the lowest turf quality and color rat- ings due the foot traffic applied through- out the winter. Plots that received iron sulfate at 2.0 lbs/1,000 ft2 (97.65 kg/ha) in combination with nitrogen applied at the 0.1 lbs N/1,000 ft2 (4.88 kg/ha) rate were able to maintain acceptable turf quality and color throughout the winter traffic period. REDUCED COST: Initial calculations derived using promising preliminary findings (effects of Civitas One applied with Sulfur DF) translate to substantial financial sav- ings. For instance, it would cost $5,470 to treat two acres of putting greens over nine months at the rates utilized in this research. This represents a $14,500 savings for the typical golf course, and $4,500,000 savings for the Pacific Northwestern United States [1,653 acres (669 hectares)]. Applications of Civitas One plus potassium phosphite (PK plus), and iron sulfate plus light rates of nitrogen would translate to similar savings and provide a fungicide alternative rotation for elemental sulfur (Sulfur DF) applications. Preliminary additional studies this spring are showing that it may not be necessary to apply these products every two weeks. Obviously, reducing the number of applications would further increase savings over traditional fungicide programs. FEWER FUNGICIDES: While these projected financial savings are significant, it is impor- tant to point out that this control is being provided without the use of traditional fungicides, which are continually facing increasing bans and restrictions across the United States, Canada and the world. Projected fungicide applications on a typical golf course for control of this pathogen range from 11 to 18 applications over a 9 month period. SULFUR AND SOIL PH (FUTURE RESEARCH): Researchers at Oregon State University have also initiated work intended to balance or offset the potential detrimental effects associated with elevated rates of sulfur and iron sulfate (i.e. acidic soil conditions) on annual bluegrass putting greens, which the above treatments will likely produce. Objectives of this research are to i) determine if sulfur applied with and without various calcium sources can reduce the number of annual fungicide applications necessary to manage Microdochium patch, ii) evaluate the effects of various sulfur application rates applied with and without differing calcium sources on annual bluegrass health and vigor, and finally iii) explore potential correlations between soil pH, turf health and Microdochium patch incidence. WCTA TABLE 1: Evaluation of fungicide alternatives on Microdochium patch disease severity, and annual bluegrass visual turf quality and color in western Oregon, 2013-2014. Unrolled |--Disease severity y --| |-- Turf quality x --| |--Turf color x --| 19 Dec 01 Mar 19 Dec 01 Mar 19 Dec 01 Mar Treatment and rate (per ha) z Sulfur DF 12.21 kg + PK plus 19.10 L ...........0.1% b 0.7% b 6.4 b 5.5 b 7.5 ns 7.5 b Sulfur DF 12.21 kg .........................................0.3% b 4.3% b 5.1 cd 4.9 b 7.5 ns 7.5 b Civitas One 27.06 L........................................3.2% ab 2.0% b 5.5 bc 5.5 b 8.0 ns 7.9 a Civitas One 27.06 L + Sulfur DF 12.21 kg + PK plus 19.10 L ............................................0.0% b 0.0% b 9.0 a 7.4 a 8.0 ns 7.5 b PK plus 19.10 L................................................0.3% b 4.0% b 5.3 c 5.3 b 7.5 ns 7.5 b Civitas One 27.06 L + Sulfur D 12.21 kg........................................0.0% b 0.0% b 9.0 a 7.6 a 8.0 ns 7.9 a Civitas One 27.06L + PK plus 19.10 L ......0.1% b 0.0% b 8.3 a 7.4 a 8.0 ns 7.9 a Untreated .........................................................4.3% a 45.0% a 4.3 d 3.5 c 7.5 ns 6.9 c Rolled |--Disease severity y --| |-- Turf quality x --| |--Turf color x --| 19 Dec 01 Mar 19 Dec 01 Mar 19 Dec 01 Mar Treatment and rate (per ha)z Sulfur DF 12.21 kg + PK plus 19.10 L ......0.2% a 0.4% b 6.6 b 5.9 ab 7.0 b 6.8 b Sulfur DF 12.21 kg .........................................5.1% a 5.7% b 6.3 bc 5.1 abc 7.0 b 6.9 ab Civitas One 27.06 L........................................0.3% a 0.5% b 6.5 bc 6.0 ab 8.0 a 7.4 a Civitas One 27.06 L + Sulfur DF 12.21 kg + PK plus 19.10 L ............................................0.0% a 0.0% b 9.0 a 4.9 bc 7.8 a 6.1 c PK plus 19.10 L................................................0.4% a 2.8% b 5.3 cd 4.8 bc 7.0 b 6.8 b Civitas One 27.06 L + Sulfur DF 12.21 kg .....................................0.0% a 0.0% b 9.0 a 5.3 abc 8.0 a 6.6 bc Civitas One 27.06 L + PK plus 19.10 L .....0.0% a 0.5% b 9.0 a 6.3 a 8.0 a 7.0 ab Untreated .........................................................6.3% a 32.5% a 4.0 d 4.0 c 7.0 b 6.6 bc z Initiated 26 Sept 2013; y Mean disease severity ratings are based on a 0 to 100% scale in three replicated plots. Means followed by the same letter are not significantly different according to Fisher's protected LSD (α=0.05); x Turf color and quality ratings are based on 1 – 9 scale (1 = worst, 9 = best, and 5.0 or greater acceptable). Means followed by the same letter are not significantly different according to Fisher's protected LSD (α=0.05). TABLE 2: Evaluation of winter fertility practices in combination with foot traffic on dis- ease severity of Microdochium patch, and annual bluegrass visual turf quality and color in western Oregon, 2013-2014. |--Disease severity y --| |-- Turf quality x --| |--Turf color x --| 19 Dec 01 Mar 19 Dec 01 Mar 19 Dec 01 Mar Treatment and rate (Kg per Ha)z 12.21 kg iron sulfate ................................18.75% abcde 31.3% bc 4.0 cd 3.8 ef 6.5 cde 7.0 bc 24.41 kg iron sulfate ................................27.50% abc 26.3% bcde 4.0 cd 4.3 cde 6.8 bcd 7.3 ab 48.82 kg iron sulfate .................................. 2.70% de 2.0% fg 6.3 b 5.1 bc 6.3 de 6.8 c 97.65 kg iron sulfate .................................. 0.05% e 0.3% g 7.8 a 4.0 def 5.5 f 4.8 d 4.88 kg nitrogen ........................................11.75% bcde 27.5% bcd 4.3 cd 4.3 cde 7.3 b 6.8 c 4.88 kg nitrogen + 12.21 kg iron sulfate ............................27.63% abc 29.3% bcd 3.8 d 4.0 def 7.3 b 7.3 ab 4.88 kg nitrogen + 24.41 kg iron sulfate .............................. 7.50% cde 8.8% efg 5.0 c 4.8 bcd 7.0 bc 7.4 ab 4.88 kg nitrogen + 48.82 kg iron sulfate ............................19.50% abcde 13.0% defg 4.3 cd 4.8 bcd 7.0 bc 7.5 a 4.88 kg nitrogen + 97.65 kg iron sulfate .............................. 0.15% e 0.4% g 7.6 a 6.4 a 7.0 bc 7.1 abc 9.76 kg nitrogen ........................................23.00% abcd 40.0% ab 3.8 d 3.8 ef 7.9 a 6.8 c 9.76 kg nitrogen + 12.21 kg iron sulfate ............................36.25% a 37.5% abc 3.5 d 3.9 def 7.3 b 7.1 abc 9.76 kg nitrogen + 24.41 kg iron sulfate ............................12.50% bcde 20.0% cdef 4.5 cd 4.5 bcde 7.0 bc 7.5 a 9.76 kg nitrogen + 48.82 kg iron sulfate ............................18.75% abcde 22.5% bcde 4.3 cd 4.3 cde 7.0 bc 7.4 ab 9.76 kg nitrogen + 97.65 kg iron sulfate .............................. 1.65% de 3.0% fg 6.6 ab 5.3 b 7.0 bc 7.3 ab Untreated ....................................................29.25% ab 55.0% a 3.8 d 3.3 f 6.0 ef 5.1 d z Initiated 26 Sept 2013; y Mean disease severity ratings are based on a 0 to 100% scale in three replicated plots. Means followed by the same letter are not significantly different according to Fisher's protected LSD (α=0.05); x Turf quality and color ratings are based on 1 – 9 scale (1 = worst, 9 = best, and 5.0 or greater acceptable). Means followed by the same letter are not significantly different according to Fisher's protected LSD (α=0.05). Microdochium, Continued From Page 24