The effects of pesticides incorporated into PHB-based polymeric matrices on the biodegradability of films and antifungal efficiency of immobilised pesticides to Botrytis cinerea was studied. The mass loss of tested PHB-based films for 2 weeks was 40-50% and after 4 weeks 92-96% of the initial mass. The fungicides Ronilan and Sumilex immobilised into the polymeric matrices did not depress the film degradation rate. PHB-based films caused changes in the soil microorganism association. Fungicides immobilised in PHB-based matrices decreased the count of the phytopathogenic fungus B. cinerca. (C) 2002 Elsevier Science Ltd. All rights reserved.