Abstract

MONROY CASTRO, Leidi Yunari  and  LIZARAZO FORERO, Luz Marina. Identification of phytopathogenic fungi associated with oak (Quercus humboldtii Bonpl.), in the municipalities of Encino (Santander), Arcabuco and Tipacoque (Boyacá). Colomb. for. [online]. 2010, vol.13, n.2, pp.347-356. ISSN 0120-0739.

The objectives of this study were to isolate and determine the presence of the pathogen Phytophthora ramorum and other potential pathogens of Quercus humboldtii, and evaluate the possibility of using the antagonistic capacity of bacteria isolated from rhizosphere and phyllosphere against them. The study was conducted in the conservation corridor Guantiva – La Rusia – Iguaque, in the municipali ties of Encino (Santander), Arcabuco and Tipacoque (Boyacá). The phytopathogenic fungi were isolated using direct seeding of leaves with symptoms of fungal infection in OGY, Sabouraud, and PDA + Lactic acid at 0.2%. We used the plate counting technique for the isolation of bacteria from rhizospheric and bulk soil. Phytophthora ramorum was not isolated, but phytopathogenic fungi of the genus Fusarium spp., and Pestalotia spp., were obtained in the isolates. Microbial populations of rhizospheric and bulk soil were scarce, exhibited low diversity, and were dominated by few mor photypes. We identified four species of bacteria: Pseudomonas fluorescens, Bacillus macerans, Bacillus subtilis and Staphylococcus epidermidis. The phyllosphere community was dominated by Pseudomonas fluorescens. The species Pseudomonas fluorescens and Bacillus subtilis did not exhibited antagonistic properties against Pestalotia spp. Further studies are required to confirm Fusarium spp., and Pestalotia spp., pathogenic activity against Quercus humboldtii.

Keywords : phyllosphere; antagonistic microorganisms; Quercus humboldtii; rhizosphere; bulk soil.

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