| Abstract/Contents: | "Fungicides were evaluated at the Rutgars Turfgrass Research Station in New Brunswick, NJ for their ability to control dollar spot. An established Penncross/Seaside bentgrass experimental putting green, maintained under standard commercial conditions at a 0.25 in cutting height, was used for this study. The turf received a total of 2.5 lb actual N (34-0-0)/1000 sq ft in 1985 applied in 0.5 lb aliquots on 14 Apr, 24 May, 6 Jun, 1 Jul and 31 Jul. Plots were 3 ft x 9 ft and treatments were arranged in a randomized complete block design with 4 replicates. Turf was irrigated as needed to avoid water stress. No insecticides or herbicides were used during the test. Sprays were applied with a CO2 compressed air sprayer, 8003E Tee-Jet nozzle, adjusted to 30 psi, in water equivelant to 1.9 gal/1000 sq ft. Fungicides were applied on 30 May (before disease development), 19 Jun and 18 Jul. Treatments were evaluated visually for number of infection centers/plot on 25 Jun, 8, 12, 23, 29, jul, 9, 14, 19, 27 Aug and 4 Sep. Natural infection was first observed and confirmed on 21 Jun. By 25 Jun, infection was uniformily distributed throughoutthe test area. All fungicide treatments provided excellent dollar spot control during the preventive application period (30 May - 18 Jul), except Rubigan 1AS (0.8 fl oz) and CGA 449 50W. As inoculum pressure intensified in late July, Rizolex 25F (6.4 fl oz) also lost effectiveness. On 9 Aug, 22 days after the last fungicide application, both the 0.15 oz and 0.30 oz rates of RH 3866 40W exhibited reduced control. Although Chipco 26019 2F 3.0 fl oz (0.75 oz ai) was not statistically better then Chipco 26019 50W 1.5 oz (0.75 oz ai) against dollar spot, it was visually superior throughout most of the study. Residual activity was excellent for Rizolex 25F 13 fl oz, and Rubigan 1AS 1.6 fl oz also provided long lasting control (22-27 days). While no phototoxicity was observed, plots treated with Rizolex 25F 39 fl oz were noticeably greener than the rest of the test." |
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