Dispersal of Inoculum of Phialophora malorum in Pear Orchards and Inoculum Redistribution in Pear Immersion Tanks. David Sugar, Oregon State University, Southern Oregon Experiment Station, Medford 97502. R. A. Spotts, Oregon State Univerity, Mid-Columbia Agricultural Research and Extension Center, Hood River 97031. Plant Dis. 77:47-49. Accepted for publication 17 September 1992. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/PD-77-0047.

Phialophora malorum was recovered from orchard air during fruit harvest and from surfaces of harvested fruit in orchard bins but not from orchard air or fruit surfaces during the growing season. Propagules of P. malorum were recovered from immersion dump tank solutions in a commercial packinghouse but not from packinghouse air. Redistribution of inoculum from infested to previously uninfested fruit was demonstrated in a research-scale immersion tank system. Side rot did not develop in surface-sterilized fruit sampled during commercial packing operations, but it did occur in samples that were not surface-sterilized. Results support the hypothesis that soilborne or deposited airborne spores may be brought into packinghouses on fruit surfaces or harvest bins and be redistributed to uninfested fruit in immersion tank solutions.

Keyword(s): postharvest decay, Pyrus communis.