Evaluation of fungicides for the control of black spot of rose, 2006

摘要

This field trial was conducted at the University of Delaware Botanic Garden in Newark, DE. Bare root hybrid tea roses were planted in the spring of 2001 in a Matapeake silt loam soil, 4 ft apart on center. Each plot consisted of two plants; pairs were8 ft apart on center and rows were spaced 10 ft apart. Experimental designwas a randomized complete block with three replications per treatment. Weeds were controlled with glyphosate and Surflan as needed, and the beds were mulched with composted woodchips for additional weed control and water conservation. No supplemental irrigation was supplied. Each rose plant was fertilized twice during the season with 6 oz 10-20-20 on 29 Apr and 3 oz on 7 Jul, and 2 Aug. Japanese beetles were controlled by six applications of lamdacyhalothrin (Battle WP) as needed. Fungicides were applied to run-off with a CO2-powered backpack sprayer equipped with a single-hollow cone nozzle (D4 and D-45 core) at 50 psi. Fungicide applications were initiated on 31 May and repeated every 14 days ending 2 Aug. Several black spot lesions were observed on a few random plants at the first application. The plots were rated on 7 and 25 Jul, and 10 Aug.