A ROT OF PEARS IN COLD STORAGE CAUSED BY MUCOR PIRIFORMIS

Abstract

Mucor piriformis Fischer was isolated from a stem-end rot of Anjou pears (Pyrus communis L.) held in cold storage. The fungus isolate proved highly pathogenic to Anjou pears and McIntosh apples, less so to Jonathan and Golden Delicious apples. It was concluded that rot of fruit in storage followed infection of the abscission layer of the stem by spores that probably originated from orchard soil. In laboratory tests, spore germination and mycelial growth of M. piriformis were very strongly inhibited by the Geigy fungicide 20072 and progressively less by thiram, sodium orthophenylphenate, and thiabendazole. M. piriformis has not been recorded previously from Canada.