BIOLOGICAL-CONTROL OF POSTHARVEST DISEASES OF APPLE AND PEAR UNDER SEMI-COMMERCIAL CONDITIONS USING 3 SAPROPHYTIC YEASTS

The yeasts Cryptococcus Laurentii (strain HRA5), Cryptococcus infirmom iniatus (strain YY6), and Rhodotorula glutinis (strain HRB6) were test ed as biocontrol agents of postharvest diseases of apple and pear in s emi-commercial and commercial trials, The yeasts effectively controlle d decay when applied in a drench or line spray. The yeasts were not ad versely affected when treated fruits were stored in a controlled atmos phere consisting of 1% oxygen and 99% nitrogen. In a commercial trial, the most effective treatments for control of blue mold of pear were a combination of C. laurentii and C. infirmo-miniatus (91% control) and the commercially recommended high rate (528 mu g/ml) of thiabendazole (88% control). In the commercial apple trial, the most effective trea tments for blue mold were C. infirmo-miniatus combined with 264 mu g/m l thiabendazole (91% control), C. infirmominiatus combined with C. lau rentii (84% control), and thiabendazole alone at 528 mu g/ml (79% cont rol). The combination of C. laurentii with 264 mu g/ml of thiabendazol e was significantly more effective for control of blue mold on pear th an thiabendazole at 528 mu g/ml whenever any thiabendazole-resistant s pores were present in the inoculum. (C) 1997 Academic Press.