Pilot tests of Candida sake (CPA-1) applications to control postharvest blue mold on apple fruit

The yeast Candida sake (strain CPA-1) was tested as a biocontrol agent of p ostharvest diseases, primarily blue mold, caused by Penicillium expansum on apple fruits. In a semi-commercial trial with non-injured fruits stored in air at 1 degreesC, a concentration of 1.6 x 10(6) colony forming units/ml (CFU/ml) of C. sake reduced the incidence of decayed fruits by more than 70 %. Over a period of three seasons, in commercial trials the efficacy of CPA -1 applied in a drench was evaluated and compared with the fungicides imaza lil and thiabendazole + folpet. The application of C. sake at 10(7) CFU/ml resulted in a reduction in the incidence of decay to a level equal to that with imazalil (375 ppm) and higher than that with thiabendazole (425 ppm) folpet (1000 ppm). Population of the biocontrol agent increased on the sur face of wounded fruits 5-fold and decreased on the surface of non-wounded f ruits more than 10-fold in the first 60 days in storage at 1 degreesC. The viability of C. sake was not reduced after 30 min immersion in benomyl, sul fur, flusilazol, ziram, thiabendazole or diphenylamine. Conversely, captan, imazalil, and ethoxyquin decreased C. sake viability and would not be comp atible with it used at commercial rates. The yeast was able to grow in cult ure at temperatures from 1 to 34 degreesC. (C) 2001 Elsevier Science B.V. A ll rights reserved.