FLUORESCENT PSEUDOMONAS SPP. AS BIOCONTROL AGENTS AGAINST FORAGE LEGUME ROOT PATHOGENIC FUNGI

Native fluorescent pseudomonads isolated from the rhizosphere of Lotus corniculatus were screened in vitro for their antagonistic activity a gainst the phytopathogenic fungi Pythium ultimum and Rhizoctonia solan i. About 12% of the bacterial isolates inhibited one or both fungi in vitro. Isolates which exhibited the greatest antagonistic activity wer e assayed in vivo against the pathogens. Three Pseudomonas fluorescens strains were selected from these assays: UP61, UP143 and VP148. These strains produced HCN and siderophores, but addition of iron to the me dium did not affect the antagonistic activity. Lytic enzymes such as c hitinase and beta-1,3-glucanase were not detected. The simultaneous in oculation of Pseudomonas strains and Rhizobium loti B816 did not affec t nitrogen fixation efficiency in L. corniculatus plants. Sterile peal was successful as a carrier for these P. fluorescens strains. (C) 199 8 Elsevier Science Ltd. All rights reserved.