Abstract
Efficacy of azoxystrobin, dichlofluanid, imazalil, kresoxim-methyl, propiconazole and triforine (standard) in the control ofDiplocarpon rosae was evaluated in the years 1997-1999. The compounds were applied as a plant spray. First treatment of plants was performed when first disease symptoms occurred on leaves and spraying was repeated 9 times at weekly intervals. In the autumn of 1999 plants not previously treated with fungicides and showing visible disease symptoms were spraye and after one, 7 and 14 days diseased leaves were sampled. Spores from leaves were transferred onto Petri dishes with potato-dextrose agar. Number of germinating spores was counted after 24 h incubation (4 Petri dishes for each compounds). After 9-weeks protection of rose shrubs with the tested compounds the spread of mycelium on new leaves was strongly inhibited. Only bupirimate at concentration 0,05% gave very poor control of D. rosae. All other tested compounds were better or as good as triforine. Reduction of concentrations used resulted in lower effectiveness. After I, 7 or 14 days from the last spraying of plants with dichlofluanid, kresoxim-methyl and triforine germination of fungus spores was below 9% except kresoxim-methyl at concentration O.Ol% after 14 days (12.5%).
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