Abstract Benomyl, methyl-1-(butylcarbamoyl)-2-benzimidazole carbamate, inhibited germination of Fusarium oxysporum. The fungicide was found to be very rapidly absorbed by the conidia. Benomyl decreased the RNA content and at high concentrations the respiration rate was inhibited. Among various respiratory enzymes that have been tested, l-malate:NAD oxidoreductase was the most sensitive to the fungicide. Protein content and amino acid uptake did not appear to be significantly altered by treatment with benomyl.