Culture method. Banana roots were carefully
separated from the soil and lightly shaken to remove
loosely attached soil as bulk soil. The roots with rhizosphere soil were cut into pieces of about 20 mm.
Ten grams of bulk soil or the mixture of root pieces
and rhizosphere soil were separately placed in 90 mL
sterile distilled water, shaken for 30 min and then
kept for 10 min. The number of FOC CFU in the
bulk and rhizosphere soils was determined by serial
dilutions on Komada’s medium (Komada, 1975). The
strains belonging to F. oxysporumwere identified by
their morphological characteristics (Komada, 1975)
and counted.