PRVNTIV ONTROL O OLLAR SPOT, R LA SPOT, AN ROWN PATH ON A RPING NTGRASS RSARH PUTTING GRN WITH VARIOUS AYR UNGIIS INTROUTION T. Lulis,. Stephens, P. Rollo,. arroll, and J.. Kaminski epartment of Plant Science The Pennslvania State Universit ollar spot (caused b the pathogen Sclerotinia homoeocarpa) is a common disease of golf course fairwas throughout Pennslvania and the entire United States. Although there are several cultural management practices that can assist in reducing disease severit, the use of protective chemicals usuall is necessar to control the disease during periods favorable for growth of the pathogen. Research into the abilit of a single earl-season fungicide application to reduce the levels of initial inoculum has shown promise. The objective of this stud was to assess the abilit of various commerciall available and an eperimental fungicide to suppress the disease following an earl season and sequential traditionall-timed applications. MATRIALS & MTHOS This one-ear field stud was initiated at the Valentine Turfgrass Research enter located in Universit Park, PA. Soil was a loam sand capped with a 4 laer of USGA sand with a ph of 7.2 and 1.8% organic matter. Turfgrass used for the fungicide evaluation was a 3-ear old stand of Penn A-4 creeping bentgrass. The area was maintained as a golf course putting green and mowed five times per week to a height of 0.110 inch. All fungicide treatments were applied with a O 2 pressuried (40 psi) spraer equipped with an air-induction flat fan nole (TeeJet, AI9508VS) calibrated to deliver 2.0 gal of water 1000 ft -2. Treatments were initiated on 23 Ma and re-applied according to the application schedule. All treatments and application dates are listed in the data tables. Plots measured 3 ft 6 ft and were arranged in a randomied complete block design with four replications. ollar spot severit was assessed b counting the number of infection centers within each plot. Red leaf spot severit (caused b the pathogen igure 1. isease pressure on a Penn A-4 creeping bentgrass green at the Valentine Turfgrass Research enter, 2016.. erthrospila) was assessed b estimating the disease severit on a 0 to 100% scale where 0 = no disease present and 100 = entire plot area affected b disease. rown patch (caused b the pathogen Rhioctonia solani) severit was assessed b estimating the disease severit on a 0 to 100% scale where 0 = no disease present and 100 = entire plot area affected b disease. Turfgrass qualit and/or color were also visuall rated on a 1 to 9 scale where 1 = entire plot brown or dead and 9 = optimum greenness and/or densit. All data were subjected to analsis of variance and means were separated at P 0.05 according to Tuke s Protected least significant difference test. RSULTS & ISUSSION ollar spot (S) was observed at the site on 10 Jun. Unfortunatel, S pressure did not increase at this site and disease severit was low (Table 1). rown patch (P) was observed at the site on 20 Jul. isease pressure increased through Jul and disease pressure peaked on 10 Aug. On 10 Aug, plots treated with rotation 1 (treatment 1) and rotation 2 (treatment 2) provided a significant reduction in disease (0% P) when compared to the non-treated 1 P a g e
control (41% P) (Table 2). On the same rating date, plots treated with an earl season application of Tartan Stressgard had some disease suppression (20% P) but were not significantl different from the aforementioned treatments or plots treated with an earl season application of Mirage (44% P) or the non-treated control plots (41% P) (Table 2). Red leaf spot (RLS) was observed at the stud site on 29 Jun. isease pressure was low and limited information is presented (Table 3). AKNOWLGMNTS We thank aer, the Pennslvania Turfgrass ouncil, and the staff at the Joseph Valentine Turfgrass Research enter for supporting this research. Table 1. ollar spot on a creeping bentgrass/annual bluegrass green following the application of aer ollar Spot Treatment and rate per 1000 ft 2 Application 10 Jun 29 Jun 20 Jul 10 Aug 1 Tartan Stressgard 1.5 fl o... A 0.3 a 0.0 a 0.0 a 0.0 a J Mirage 1 fl o aconil Ultre 3.2 o 2 Tartan Stressgard 1.5 fl o... A 0.3 a 0.0 a 0.0 a 0.3 a 26GT 2 fl o 3 Tartan Stressgard 1.5 fl o... A 0.0 a 0.0 a 2.5 a 0.8 a 4... 0.0 a 0.0 a 0.0 a 2.3 a 5 Nontreated... - 0.3 a 0.3 a 0.3 a 2.0 a ollar spot severit was assessed b counting the number of infection centers per plot. Treatments were applied on the following dates: A = 25 Apr, = 23 Ma, = 6 Jun, = 20 Jun, = 5 Jul, = 19 Jul. the Tuke s least significant difference test. 2 P a g e
Table 2. rown patch on a creeping bentgrass/annual bluegrass green following the application of aer rown Treatment and rate per 1000 ft 2 Application 20 10 1 Tartan Stressgard 1.5 fl o... A 0.0 0.0 J Mirage 1 fl o aconil Ultre 3.2 o 2 Tartan Stressgard 1.5 fl o... A 0.0 0.0 26GT 2 fl o 3 Tartan Stressgard 1.5 fl o... A 3.8 4... 0.0 43. 5 Nontreated... - 3.8 41. rown patch (P) was visuall assessed on a 0 to 100% scale where 0 = no disease present and 100 = entire plot area affected b P. Treatments were applied on the following dates: A = 25 Apr, = 23 Ma, = 6 Jun, = 20 Jun, = 5 Jul, = 19 Jun. the Tuke s least significant difference test. 3 P a g e
Table 3. Red leaf spot on a creeping bentgrass/annual bluegrass green following the application of aer Red leaf spot Treatment and rate per 1000 ft 2 Application code 29 Jun 1 Tartan Stressgard 1.5 fl o... A 0.0 a J Mirage 1 fl o aconil Ultre 3.2 o 2 Tartan Stressgard 1.5 fl o... A 0.0 a 26GT 2 fl o 3 Tartan Stressgard 1.5 fl o... A 1.3 a 4... 0.0 a 5 Nontreated... - 0.8 a Red leaf spot (RLS) was visuall assessed on a 0 to 100% scale where 0 = no disease present and 100 = entire plot area affected b RLS. Treatments were applied on the following dates: A = 25 Apr, = 23 Ma, = 6 Jun, = 20 Jun, = 5 Jul, = 19 Jul. the Tuke s least significant difference test. 4 P a g e
Table 4. Qualit on a creeping bentgrass/annual bluegrass green following the application of aer Qualit Treatment and rate per 1000 ft 2 Application 10 Jun 29 Jun 20 Jul 10 Aug 1 Tartan Stressgard 1.5 fl o... A 8.0 a 8.0 a 8.0 a 8.0 a J Mirage 1 fl o aconil Ultre 3.2 o 2 Tartan Stressgard 1.5 fl o... A 8.0 a 8.0 a 8.0 a 8.0 a 26GT 2 fl o 3 Tartan Stressgard 1.5 fl o... A 8.0 a 8.0 a 8.0 a 7.3 ab 4... 8.0 a 8.0 a 8.0 a 6.8 b 5 Nontreated... - 8.0 a 8.0 a 8.0 a 6.8 b Qualit was visuall assessed on a 1 to 9 scale where 1 = entire plot brown and 9 = optimum uniformit and densit. Treatments were applied on the following dates: A = 25 Apr, = 23 Ma, = 6 Jun, = 20 Jun, =5 Jul, = 19 Jul. the Tuke s least significant difference test. 5 P a g e
Table 5. olor on a creeping bentgrass/annual bluegrass green following the application of aer olor Treatment and rate per 1000 ft 2 Application 10 Jun 29 Jun 20 Jul 10 Aug 1 Tartan Stressgard 1.5 fl o... A 8.0 a 8.0 a 8.0 a 8.0 a J Mirage 1 fl o acinil Ultre 3.2 o 2 Tartan Stressgard 1.5 fl o... A 8.0 a 8.0 a 8.0 a 8.0 a 26GT 2 fl o 3 Tartan Stressgard 1.5 fl o... A 7.5 a 7.5 a 7.8 a 7.0 b 4... 7.8 a 8.0 a 8.0 a 6.5 b 5 Nontreated... - 7.5 a 7.8 a 7.5 a 6.5 b olor was visuall assessed on a 1 to 9 scale where 1 = entire plot brown and 9 = optimum greenness. Treatments were applied on the following dates: A = 25 Apr, = 23 Ma, = 6 Jun, = 20 Jun, = 5 Jul, = 19 Jul. the Tuke s least significant difference test. 6 P a g e