[Phytopathogenicity of Pythium spp.from the irrigation water of the Poniente Almeriense (south-eastern Spain)].

Phytopathogenicity was assessed of 55 isolates of Pythium spp. from the irrigation water of the district of the Poniente Almeriense (Almería, south-eastern Spain). The isolates were 16 of Pythium catenulatum, two of Pythium diclinum, two of Pythium paroecandrum and 35 of asexual forms with filamentous sporanges. Each Pythium isolate was tested with three types of damping-off phytopathogenicity tests with cucumber var. Ashley, in pots at 25 degrees C, varying the inoculation time (pre-seeding, pre-emergence and post-emergence). 83.64% of the isolates were found to be phytopathogenic. Phytopathogenic isolates were detected in all of the identified species. Mortality rates (%) decreased with the delay in inoculation time after the seeding. The isolates showing most growth in vitro were the most phytopathogenic.