Turkish Journal of Agriculture and Forestry




The effects of various fungicides on spore germination, mycelial growth, seed transmission, and infection by Septoria petroselini Desm., the causal agent of Septoria blight of parsley, were determined in this study. Eleven fungicides (azoxystrobin, benomyl, captan, copper oxychloride, kresoxim-methyl mancozeb, maneb, propineb, tebuconazole, thiram, and trifloxystrobin) were tested at various concentrations ranging from 0.025 to 50 mg l^{-1} in spore germination and mycelial growth assays. Tebuconazole was the most effective fungicide in all the experiments, with an EC_{50} value < 0.052 mg l^{-1}, followed by azoxystrobin, captan, and trifloxystrobin, with EC_{50} values of 0.053, 0.06, and 0.066 mg l^{-1}, respectively. Many of the fungicides were effective on spore germination in PDA medium at concentrations ranging from 0.052 mg l^{-1} (Tebuconazole) to 23.032 mg l^{-1} (copper oxychloride). Captan, mancozeb, maneb, and thiram were very effective at reducing spore germination, but were less effective at reducing mycelial growth, for which their EC_{50} values were up to 735-, 192-, 192-, and 191-fold higher, respectively. Seed transmission of Septoria blight of parsley was controlled by tebuconazole, benomyl, azoxystrobin, kresoxim-methyl, and captan, which had inhibition rates of up to 95%, 93%, 93%, and 66%, respectively. Azoxystrobin, benomyl, kresoxim-methyl, trifloxystrobin, and tebuconazole inhibited Septoria blight in vivo, but captan, mancozeb, and maneb were effective at reducing the number of lesions only when they were applied before inoculation. Copper oxychloride, the most extensively used fungicide for controlling Septoria blight by parsley growers, was surprisingly the least effective in all the experiments.

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