Eleven chemicals that inhibit biosynthesis of ergosterol in fungi were compared as fungicides against Phymatotrichum omnivorum (PO) in poison agar tests. Propiconazole and DPXH6573, triazole derivatives, and fenarimol and nuarimol, pyrimidine derivatives, were active in inhibiting growth of PO in the parts per billion range. The imidazole derivatives were less active against PO. Slow release formulations of triazole fungicides reduced phytotoxicity while retaining excellent fungicidal properties.