In accordance with, the present invention, there is provided an antimicrobial composition comprising an aqueous solution containing copper and/or zinc ions, optionally a hydroxide salt, and phosphorous acid. The composition, is additionally sporicidal and scleroticidal when combined with a salt of nitrous acid such as sodium nitrite. The present invention may also include chemicals containing the phosphite or phosphonaie group (PO/l which can inhibit the formation of scierotia at concentrations that are readily achievable for agricultural applications. Compositions of the present invention, inhibit, scierotia formation by fungi and may therefore be used in the field to prevent the continuation and advancement of pathogenie fungi.