Evaluation of multiple fungicide programs for disease control on creeping bentgrass 2013

摘要

Multiple fungicide programs were evaluated for disease control at the University of Missouri Turfgrass Research Facility in Columbia, MO on 'Penn A-4' creeping bentgrass green with a 90:10 sand/peat root zone mix. Mowing was performed at a height of 0.13-in., three and five times weekly from 2 Apr to 7 Jun and 7 Jun to 9 Sep, respectively. Nitrogen was applied using Signature (13-2-13) on 15 and 22 Apr at 0.20 lb N/1000 sq ft. From 23 May to 3 Sep, 0.25 lb N/1000 sq ft was supplied every two to threeweeks with UMaxx (47-0-0) + Knife Plus (12-0-0) or Ferromec (10-2-4) + micros (0.01 lb N/1000 sq ft). Revolution (6.0 fl oz/1000 sq ft) was applied every 28 days starting on 8 May. Plots were 5 ft x 5 ft and arranged in a randomized complete block design with four replications. Treatments were applied in water equivalent to 2 gal/1000 sq ft with a CO2-powered sprayer at 26 psi using TeeJet 8008 nozzles. Four preventive fungicide programs (see table for application details) were initiated on 8 May following a 14 day application interval. On 13 May, rye grain (Secale cereale L.) infested with three isolates of Sclerotinia homoeocarpa was uniformly applied at a volume of 1.52-in.3 per plot using a small broadcast spreader. Inoculum was left on the turf surface for 2 days. Disease incidence, severity, and turfgrass quality were assessed every 14 days from initial symptom development. Select rating dates are presented in the tables below to demonstrate disease progress and turfgrass quality in untreated control plots. Disease severity was assessed as a visual estimate of the percent symptomatic area and incidence was determined by the number of infection centers per plot. Turfgrass quality was evaluated using a 1 to 9 scale (9=best, 5=acceptable) based on color, density, and uniformity. Data were subjected to analysis of variance and means separation using Fishers Protected LSD (P=0.05).