A root rot of bean caused by a species of Aphanomyces was found at Valla, New South Wales. In the field, nine bean cultivars were susceptible but the experimental cultivar H & R no. 1, known to be resistant to A. euteiches f. sp. phaseoli in the United States, was also resistant to the root rot at Valla. The New South Wales isolates of Aphanomyces were highly pathogenic to beans and mildy pathogenic to peas. Fenaminosulf, applied immediately before planting as a spray to an open furrow (0.7–7 g a,i. m−2 of row, 0.2 m wide), controlled the bean root rot to varying degrees depending on soil moisture conditions immediately after sowing. Seed treatment with fenaminosulf (2.5–10 g a.i/100 kg seed) failed to control the bean root rot in the field.