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 NaHCO3on mycelial biomass accumulation, fresh spore suspensions were added into100 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 replicatedb three times and the experiment was repeated.