Sensitivities of various Oomycetes to hymexazol and metalaxyl

The effect of hymexazol on the linear extension of hyphae of a range of Oomycetes was examined. Twenty-five species were compared using four fungicide concentrations. Cluster analysis was used to look for similarities between species. The response of each taxon to the different concentrations of hymexazol was modelled. The parameters of these curves were then subjected to multivariate analysis. Both analyses revealed close relationships between the sensitivity to the fungicide and the current classification of the Oomycetes. Comparisons were made with the effect of metalaxyl on the same isolates.