Research Update: Effects of Alterna5ves to Tradi5onal Fungicide and Winter Fer5liza5on Prac5ces on Microdochium Patch Clint Ma)ox, Alec Kowalewski, and Brian McDonald Department of Hor<culture, Oregon State University Introduc5on: Microdochium patch can be observed year- around 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 pumng greens from September through May, and under favorable condi<ons, can injure or kill significant amounts of turf which greatly disrupts the aesthe<cs and playability of the pumng 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 3 to 4 weeks to pumng greens throughout the 9 month period of disease ac<vity are the primary means for providing control of this pathogen, which equates to roughly $20,000 annually per golf course. In recent years, increasing pes<cide bans and restric<ons have limited the op<ons for managing pest problems including diseases like Microdochium Patch. Considering this, li)le informa<on exists regarding alterna<ve integrated management strategies that might significantly reduce or eliminate the need for fungicide applica<ons. The overall objec<ve of this research theme is the explora<on of fungicide alterna<ve management of Microdochium patch on annual bluegrass pumng greens. Research Update (September 26, 2013 to March 01, 2014): 1
In con<nued explora<on of fungicide alterna<ve products and prac<ces for management of Microdochium patch a series of experiments were ini<ated at the Oregon State University Lewis Brown Hor<culture Farm and at the Washington State University Goss Research Farm, Puyallup, WA on September 26, 2013 (Image 1). Alterna(ves to Tradi(onal Fungicides (Table 1 and Image 2): The objec<ve of this study was to evaluate the efficacy of alterna<ves to tradi<onal fungicides for the control of Microdochium patch on an annual bluegrass pumng green. Fungicide alterna<ve treatments applied every other week since September 26, 2014 included Sulfur DF (0.25 lbs/1,000 c 2 ; 12.21 kg/ha), Civitas One (8.5 oz/1,000 c 2 ; 27.06 L/ha), PK plus L (6.0 oz/1,000 c 2 ; 19.10 L/ha), as well as all possible combina<ons of these products, in comparison to an untreated check plot (Table 1). Rolling was also inves<gated as a cultural prac<ce to reduce disease in combina<on with the fungicide alterna<ve treatments. The untreated check plots averaged 45.0 percent disease cover on ra<ng date, Mar 1, 2014 (Table 1). When Civitas One was mixed with any of the fer<lizer combina<ons (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 pumng green quality. In March, rolling reduced disease severity only when the products discussed above where not applied. When these products were applied, rolling had li)le effect on disease severity, or turf color and quality. Rolling in combina<on with all plots where Civitas One was applied began to show signs of abio<c damage on 09 Jan 2014. The manufacturers of Civitas One recommend only applying it when 2
the turf is ac<vely growing. This suggests that the decreasing temperatures in combina<on with rolling led to a decline in turf quality. Winter Fer(liza(on Prac(ces (Table 2 and Image 3): The objec<ve of this study was to evaluate the efficacy of winter fer<lity prac<ces in combina<on with simulated traffic in order to determine their effects on the suppression of Microdochium patch and turfgrass recovery on annual bluegrass in western Oregon, 2013-2014. Treatments applied in this study every other week beginning September 26, 2014 included iron applied at 0.0, 0.25, 0.5, 1.0 and 2.0 lbs/1,000 c 2 (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 c 2 (0.0, 4.88 and 9.76 kg/ha) as well as all possible combina<ons of these iron and nitrogen rates (Table 2). All treatments then received weekly foot traffic at a rate equivalent to Trys<ng Tree Golf Course in Corvallis, OR. As of March 1, 2014, the untreated control plots averaged the highest disease severity, 55. Plots that received iron at 2.0 lbs/1,000 c 2 (97.65 hg/ha) with nitrogen applied at the 0.1 lbs N/1,000 c 2 (4.88 kg/ha) rate and without nitrogen had the lowest percent of disease (Table 2 and Image 3). When iron was applied at 2.0 lbs/1,000 c 2 (97.65 kg/ha) in combina<on with nitrogen at the 0.2 lbs N/1,000 c 2 (9.76 kg/ha) rate disease pressure increased. While iron applied at 2.0 lbs/1,000 c 2 (97.65 kg/ha) without nitrogen provided some of the lowest disease percentage it also produced some of the lowest turf quality and color ra<ngs due the foot traffic applied throughout the winter. Plots that received iron at 2.0 lbs/1,000 c 2 (97.65 kg/ha) in combina<on with nitrogen applied at the 0.1 lbs 3
N/1,000 c 2 (4.88 kg/ha) rate were able to maintain acceptable turf quality and color throughout the winter traffic period. Reduced Cost: Ini<al calcula<ons derived using promising preliminary findings (effects of Civitas One applied with Sulfur DF) translates to substan<al financial savings. For instance, it would cost $5,470 to treat 2 acres of pumng greens over 9 months at the rates u<lized in this research. This represents a $14,500 savings for the typically golf course, and $4,500,000 saving for the Pacific Northwestern United States [1,653 acres (669 hectares)]. Applica<ons of Civitas One plus potassium phosphite (PK plus), and iron plus light rates of nitrogen would translate to similar savings and provide a fungicide alterna<ve rota<on for elemental sulfur (Sulfur DF) applica<ons. Preliminary addi<onal studies this spring are showing that it may not be necessary to apply these products every two weeks. Obviously, reducing the number of applica<ons would further increase savings over tradi<onal fungicide programs. 4
Fewer Fungicides: While these projected financial savings are significant, it is important to point out that this control is being provided without the use of tradi<onal fungicides, which are con<nually facing increasing bans and restric<ons across the United States, Canada and the world. Projected fungicide applica<ons on a typical golf course for control of this pathogen range from 11 to 18 applica<ons over a 9 month period. Sulfur and Soil ph (Future Research): Researchers at Oregon State University have also ini<ated work intended to balance or offset the poten<al detrimental effects associated with elevated rates of sulfur and iron (i.e. acidic soil condi<ons) on annual bluegrass pumng greens, which the above treatments will likely produce. Objec<ves of this research are to i) determine if sulfur applied with and without various calcium sources can reduce the number of annual fungicide applica<ons necessary to manage Microdochium patch, ii) evaluate the effects of various sulfur applica<ons rates applied with and without differing calcium sources on annual bluegrass health and vigor, and finally iii) explore poten<al correla<ons between soil ph, turf health and Microdochium patch incidence. 5
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 ft 2 ; 12.21 kg/ha) and Civitas One (8.5 oz/1,000 ft 2 ; 27.06 L/ha), applied every 2 weeks (left) in comparison to the control (right) observed November 20, 2013 (applications initiated September 26, 2013). 6
Image 3: Effects of iron, applied at 2.0 lbs FeSO4/1,000 ft 2 (97.65 kg FeSO4/ha) every 2 weeks (left), and nitrogen (46-0-0), applied at 0.1 lbs N/1,000 ft 2 (4.88 kg N/ha), plus iron, at 2.0 lbs FeSO4 per 1,000 ft 2 (97.65 kg FeSO4/ha) every 2 weeks (right) on Microdochium patch incidence and annual bluegrass putting green health, picture collected Jan 10, 2014 (4 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 7
Table 1: Evalua<on of fungicide alterna<ves on Microdochium patch disease severity, and annual bluegrass visual turf quality and color in western Oregon, 2013-2014. Unrolled Treatment and rate (per ha) Sulfur DF 12.21 kg + PK plus 19.10 L - - Disease severity - - - - Turf quality - - Turf color 19 Dec 01 Mar 19 Dec 01 Mar 19 Dec 01 Mar 0.1 b 0.7 b 6.4 b 5.5 b 7.5 ns 7.5 b Sulfur DF 12.21 kg Civitas One 27.06 L Civitas One 27.06 L + Sulfur DF 12.21 kg + PK plus 19.10 L PK plus 19.10 L Civitas One 27.06 L + Sulfur D 12.21 kg Civitas One 27.06L + PK plus 19.10 L Untreated Rolled Treatment and rate (per ha) Sulfur DF 12.21 kg + PK plus 19.10 L. Sulfur DF 12.21 kg. 0.3 b 4.3 b 5.1 cd 4.9 b 7.5 ns 7.5 b 3.2 ab 2.0 b 5.5 bc 5.5 b 8.0 ns 7.9 a 0.0 b 0.0 b 9.0 a 7.4 a 8.0 ns 7.5 b 0.3 b 4.0 b 5.3 c 5.3 b 7.5 ns 7.5 b 0.0 b 0.0 b 9.0 a 7.6 a 8.0 ns 7.9 a 0.1 b 0.0 b 8.3 a 7.4 a 8.0 ns 7.9 a 4.3 a 45.0 a 4.3 d 3.5 c 7.5 ns 6.9 c - - Disease severity - - - - Turf quality - - Turf color 19 Dec 01 Mar 19 Dec 01 Mar 19 Dec 01 Mar 0.2 a 0.4 b 6.6 b 5.9 ab 7.0 b 6.8 b 5.1 a 5.7 b 6.3 bc 5.1 abc 7.0 b 6.9 ab 8
Civitas One 27.06 L. Civitas One 27.06 L + Sulfur DF 12.21 kg + PK plus 19.10 L. PK plus 19.10 L. Civitas One 27.06 L + Sulfur DF 12.21 kg. Civitas One 27.06 L + PK plus 19.10 L. 0.3 a 0.5 b 6.5 bc 6.0 ab 8.0 a 7.4 a 0.0 a 0.0 b 9.0 a 4.9 bc 7.8 a 6.1 c 0.4 a 2.8 b 5.3 cd 4.8 bc 7.0 b 6.8 b 0.0 a 0.0 b 9.0 a 5.3 abc 8.0 a 6.6 bc 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 Ini<ated 26 Sept 2013; y Mean disease severity ra<ngs are based on a 0 to 100 scale in three replicated plots. Means followed by the same le)er are not significantly different according to Fisher s protected LSD (α=0.05); x Turf color and quality ra<ngs are based on 1 9 scale (1 = worst, 9 = best, and 5.0 or greater acceptable). Means followed by the same le)er are not significantly different according to Fisher s protected LSD (α=0.05). 9
Table 2: Evalua<on of winter fer<lity prac<ces in combina<on with foot traffic on disease severity of Microdochium patch, and annual bluegrass visual turf quality and color in western Oregon, 2013-2014. Treatment and rate (Kg per Ha) 12.21 kg iron - - Disease severity - - Turf quality - - Turf color 19 Dec 01 Mar 19 Dec 01 Mar 19 Dec 01 Mar 18.75 abcde 31.3 bc 4.0 cd 3.8 ef 6.5 cd e 7.0 bc 24.41 kg iron 27.50 abc 26.3 bc de 4.0 cd 4.3 cde 6.8 bc d 7.3 ab 48.82 kg iron 2.70 de 2.0 fg 6.3 b 5.1 bc 6.3 d e 6.8 c 97.65 kg iron 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 bc d 4.3 cd 4.3 cde 7.3 b 6.8 c 4.88 kg nitrogen + 12.21 kg iron 27.63 abc 29.3 bc d 3.8 d 4.0 def 7.3 b 7.3 ab 4.88 kg nitrogen + 24.41 kg iron 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 19.50 abcde 13.0 def g 4.3 cd 4.8 bcd 7.0 bc 7.5 a 4.88 kg nitrogen + 97.65 kg iron 0.15 e 0.4 g 7.6 a 6.4 a 7.0 bc 7.1 ab c 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 36.25 a 37.5 ab c 3.5 d 3.9 def 7.3 b 7.1 ab c 9.76 kg nitrogen + 24.41 kg iron 12.50 bcde 20.0 cd ef 4.5 cd 4.5 bcd e 7.0 bc 7.5 a 10
9.76 kg nitrogen + 48.82 kg iron 18.75 abcde 22.5 bc de 4.3 cd 4.3 cde 7.0 bc 7.4 ab 9.76 kg nitrogen + 97.65 kg iron 1.65 de 3.0 fg 6.6 a b 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 Ini<ated 26 Sept 2013; y Mean disease severity ra<ngs are based on a 0 to 100 scale in three replicated plots. Means followed by the same le)er are not significantly different according to Fisher s protected LSD (α=0.05); x Turf quality and color ra<ngs are based on 1 9 scale (1 = worst, 9 = best, and 5.0 or greater acceptable). Means followed by the same le)er are not significantly different according to Fisher s protected LSD (α=0.05). 11