Abstract:

The aim of this research was to isolate a strain of potential antagonistic yeast from soil samples collected from
unsprayed orchards, and to test the control efficacy against postharvest decay of strawberries. By molecular biological
identification and biochemical examination, the antagonistic strain was identified as Pichia caribbica. The antagonist showed
significant biological control efficacy against postharvest decay of strawberries caused by gray mold and Rhizopus which
was significantly affected by its concentration: the higher the concentration of the antagonist, the lower the disease incidence.
P. caribbica at 1× 109 cells /mL was able to inhibit completely gray mold decay and Rhizopus decay of strawberries after
3 d incubation at 20 ℃, while the control fruit showed 92.5% decay incidence when challenged with B.cinerea spores
suspension of 1 × 105 spores/mL, and 100% decay incidence when challenged with R. stolonifer spores suspension of 5 × 104
spores/mL, respectively. Rapid growth of the antagonist in wounds was observed during the first day at 20 ℃, and during the
first 5 d at 4 ℃. P. caribbica significantly reduced the natural development of decay and did not impair the fruit quality when
stored at 20 ℃ for 5 d.

Key words: screening, identification, Pichia caribbica, postharvest decay, strawberries, biocontrol