Evaluation of fungicides for management of powdery mildew on Gerbera daisy, 2004.

摘要

The evaluation was conducted in a polyhouse on the University of Georgia Griffin Campuslocated in Griffin, GA. Plants were maintained in 1 gal containers with Sunshine GBX potting mix, watered by drip irrigation as needed, and fertilized weekly with Peters 15-15-15 Geranium Special. Treatments were initiated on 18 May and were applied at 7or 14-day intervals. All fungicides were applied to run-off with a CO2 pressurized sprayer using a TeeJet 11002VS nozzle at 25 psi. Four replications of two plants each were arranged in a randomized complete block design. Plants had an average of 25.8 leaves at the start of the trial. The progression of powdery mildew resulting from natural infection on each plant was estimated weekly using the Horsfall-Barratt scale (1 = no disease, 2 = 0- 3%, 3 = 3-6%, 4 = 6-12%, 5 = 12-25%, 6 = 25-50%, 7 = 50-75%, 8 = 57-87%, 9 = 87-94%, 10 = 94-97%, 11 = 97-100%, 12 = 100% of leaves with lesions) and the ratings were converted to percent midpoint values for analysis.