Biological control of blue mould on apple by a strain of Candida sake under several controlled atmosphere conditions

The biocontrol potential of the yeast Candida sake (CPA-1) against Penicill ium expansum decay of apples under several controlled atmosphere conditions was investigated. In a laboratory trial under different commercial cold st orage conditions, increasing concentrations of C. sake improved decay contr ol. A maximum reduction of decay was achieved at 3% O-2-3% CO2 atmosphere. It amounted to a 97% lesion reduction after treatment with a suspension con taining 2.4 x 10(6) CFU/ml of C. sake (CPA-1). In a semi-commercial trial a t 1 degrees C with wounded fruits, the reduction in decay diameter caused b y C. sake exceeded 80% after 60 days at 21% O-2 and 60% after 120 days of s torage under controlled atmosphere conditions. For seven controlled atmosph ere conditions studied, a significant influence by C. sake on the P. expans um decay was observed, and the lesion size was reduced more than 70% by C. sake at 10(7) CFU/ml. The populations of C. sake (CPA-1) on the apple surfa ce followed the same pattern under all controlled atmosphere conditions stu died. They decreased 4-10-fold during the first 2 weeks, followed by an inc rease to the initial level after 45 days, and thereafter the count remained constant for the period of 90 days examined. This indicated the capacity o f C. sake (CPA-1) to colonize the surface of apples under various storage c onditions. The ability to colonize was even higher in apple wounds. (C) 200 0 Elsevier Science B.V. All rights reserved.