Envionmental and consumer concerns have focused interest on the development of biological control
as an alternative, environmentally-friendly strategy for the protection of agricultural and horticultural
crops against phytopathogens. Biological control agents. producing a variety of secondary metabolites
and hydrolytic enzymes, have been identified among fungi, actinomyceles and bacteria. Pseudomonas
fluorescens FII3 and Stenotrophomonas maltophilia W81 inhibit growth of the phytopathogenic
fungus Pythium ultimum in vitro and are capable of protecting sugar beet against the effects of
damping-off under soil conditions. Transposon mutagenesis of strains FIl3 and W81 has
demonstrated that the biocontrol abilities of these strains are mediated by 2,4-diacetylphloroglucinol
(pm...) or lytic enzyme production, respectively. Globodera roslochiensis is a phytopathogenic cyst
neml1.tode of major agronomic importance. Purified PHL, lytic enzymes, and chitinolytic or
phloroglucinol-producing bacterial inoculants negatively influence hatch of G. rostochiensis eggs and
decrease subsequent viability of juvenile cyst nematodes in vitro. Similar results were obtained under
soil conditions