Correlation of Lipid Peroxidation in Botrytis cinerea Caused by Dicarboximide Fungicides with Their Fungicidal Activity.

Dicarboximide fungicides iprodione, vinclozolin, and procymidone were examined for their capacity to inhibit mycelial growth, to cause cellular leakage, and to cause lipid peroxidation on Botrytis cinerea isolate BC2. All three fungicides effectively inhibited the mycelial growth of the fungi. The IC(50) values were found to be about 2 µM for all three fungicides, indicating that the fungicidal activity of the individual fungicides was almost the same. The fungicides caused significant cellular leakage and lipid peroxidation on the fungi in a concentration-dependent manner. Fungicidal activity of the three individual fungicides on inhibiting mycelial growth of the fungi correlated positively well with both cellular leakage and lipid peroxidation that were caused by the respective fungicides. Positive correlations were also found between the degree of cellular leakage and lipid peroxidation following treatment with the fungicides. Our results support the view that dicarboximide fungicides exert their fungicidal activity mainly through membrane lipid peroxidation and subsequent cellular leakage from the treated fungi.