The mycelial expansion rate of P. expansum was measured on PDA plate as follows. A 5 mm diameter plug of mycelial agar was placed on the center of a 9 cm diameter petri dish containing 25 mLPDA supplemented with 0 or 0.6% NaHCO3. The petri dishes were incubated at 25◦C and the colony diameter was measured by decussation method daily. To evaluate the effect of NaHCO3 on mycelial biomass accumulation, fresh spore suspensions were added in to100 mL PDB medium with 0 or 0.6% NaHCO3 to obtain a final concentration of 1.0 × 106 spores/mL. After incubation of 12, 24, 36 and 48 h, the dry weight of hypha was measured after repeated washing of mycelial pellets with distilled water and during at 70◦C in hot-air oven to a constant weight. Each treatment was replicated three times and the experiment was repeated.