Postharvest biological control of gray mold rot of pear with Cryptococcus laurentii

Cryptococcus laurentii was evaluated for its activity in reducing postharvest gray mold decay of pear caused by Botrytis cinerea. Washed cell suspensions of yeast controlled gray mold better than yeast in culture broth. Treatment of wounds with autoclaved cell cultures or cell-free culture filtrate did not prevent decay. The interval between inoculation with the pathogen and application of the antagonist significantly influenced the efficacy of biocontrol. Efficacy was maintained when C. laurentii was applied simultaneously or prior to inoculation with B. cinerea but reduced if applied after inoculation with B. cinerea. The concentrations of antagonist had significant effects on biocontrol effectiveness: the higher the concentrations of the antagonist, the lower the disease incidence and the smaller the lesion diameter regardless of whether the fruit was stored at 25 °C for 7 days or 2 °C for 30 days followed by 20 °C for 7 days. The efficacy of C. laurentii was enhanced by the addition of 2% CaCl2. C. laurentii significantly reduced the natural development of decay and did not impair quality parameters of fruit following storage at 2 °C for 60 days followed by 20 °C for 15 days.