STRUCTURE-ACTIVITY-RELATIONSHIPS OF EFFECT OF ARYLTIN COMPOUNDS ON CERATOCYSTIS-ULMI

The effect of aryltin compounds (Ar4Sn and Ar3SnCl) on the growth of C eratocystis ulmi, the causative agent of Dutch elm disease, was studie d in shake culture. In all cases, the triaryltins were more effective than the tetra-aryltins as inhibitors of C. ulmi in vitro. Furthermore , substitution on the phenyl ring at the meta- and para- positions in the triaryltins did not have a major effect on the biocidal activity f or the substituted triaryltins. Quantitative structure-activity relati onships (QSARs) gave support to the idea that the species responsible for the inhibition of the fungus is the triaryltin cation. The QSARs f urther suggest that the interaction of the triaryltin cation with the fungal cell wall of C. ulmi is by a non-specific mechanism.