Effect of novel water-soluble polymeric forms of sorbic acid against Fusarium oxysporum f. sp radicis-cucumerinum

New controlled release water-soluble formulations of sorbic (2,4-hexadienoi c) acid were prepared and their inhibitory activity on mycelium growth of F usarium oxysporum f. sp. radicis-cucumerinum was evaluated. The new product s are epoxidized polymers of polyvinylpyrrolidone (PVP) containing covalent ly bonded sorbic acid (polymeric esters of sorbic acid) and complexes of PV P with hydrogen bonded sorbic acid, characterized by controlled release of sorbic acid. It was shown that the polymeric complexes of sorbic acid with PVP were more effective fungicidal agents than sorbic acid polymeric esters . In all cases the activity of polymeric derivatives (esters and complexes) was increased by lowering the molecular weight of the polymeric carriers. Controlled release formulations of these polymeric derivatives are new prom ising products due to their low toxicity, wide range of efficient concentra tions for application and ability to regulate lyophilicity. Our data contri bute to the understanding of the action mechanism of various polymeric sorb ic acid formulations and can result in products which are particularly suit able for food and feed protection applications.