RESUMO
The pathogenicity of seven strains of Fusarium equiseti isolated from seabed soil was evaluated on different host plants showing pre and post emergence damage. Radial growth of 27 strains was measured on culture media previously adjusted to different osmotic potentials with either KCl or NaCl (-1.50 to - 144.54 bars) at 15º, 25º and 35º C. Significant differences and interactive effects were observed in the response of mycelia to osmotic potential and temperature.
Assuntos
Cloreto de Potássio/análise , Cloreto de Sódio/análise , Microbiologia Ambiental , Fusarium/isolamento & purificação , Fusarium/patogenicidade , Meios de Cultura/isolamento & purificação , Micélio/crescimento & desenvolvimento , Micélio/patogenicidade , Microbiologia do Solo , Solos Salitrosos/análise , Métodos , Pressão Osmótica , Plantas , MétodosRESUMO
The pathogenicity of seven strains of Fusarium equiseti isolated from seabed soil was evaluated on different host plants showing pre and post emergence damage. Radial growth of 27 strains was measured on culture media previously adjusted to different osmotic potentials with either KCl or NaCl (-1.50 to -144.54 bars) at 15°, 25° and 35° C. Significant differences and interactive effects were observed in the response of mycelia to osmotic potential and temperature.
RESUMO
The pathogenicity of seven strains of Fusarium equiseti isolated from seabed soil was evaluated on different host plants showing pre and post emergence damage. Radial growth of 27 strains was measured on culture media previously adjusted to different osmotic potentials with either KCl or NaCl (-1.50 to - 144.54 bars) at 15º, 25º and 35º C. Significant differences and interactive effects were observed in the response of mycelia to osmotic potential and temperature.
RESUMO
Thirty-one soil samples from 14 different fields of Guatemala melon with vine decline symptoms were analyzed for the presence of organisms associated with the disease. With a soil-dilution plating method, only Macrophomina phaseolina was detected in five samples. With a melon bait plant technique, Olpidium bornovanus, often together with Melon necrotic spot virus (MNSV), was found in nearly all the samples, corresponding with all the fields studied. Other pathogens that were detected less frequently included Pythium aphanidermatum, Monosporascus cannonballus, and Rhizoctonia solani. Consequently, O. bornovanus and MNSV were uniquely associated with disease occurrence and thus are the most probable cause of melon vine decline in the fields studied.