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Postharvest Pathology and Mycotoxins

The Importance of Wounds in Infection of Pear Fruit by Phialophora malorum and the Role of Hydrostatic Pressure in Spore Penetration of Wounds. David Sugar, Oregon State University, Southern Oregon Experiment Station, 569 Hanley Road, Medford 97502; R. A. Spotts, Mid-Columbia Agricultural Research and Extension Center, Hood River 97031. Phytopathology 83:1083-1086. Accepted for publication 11 May 1993. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/Phyto-83-1083.

Pear fruits (cv. Bosc) were not infected by Phialophora malorum via lenticels under conditions of bruising, hydrostatic pressure, or 6 mo of exposure to a range of spore concentrations without puncture wounding. Methylene blue solution penetrated approximately 2% of fruit lenticels examined. Dye penetration into fruit was facilitated by artificial bruising of lenticels. Hydrostatic pressure from immersion of fruit in aqueous suspensions of P. malorum spores at depths from 10 to 100 cm influenced the frequency of infection in fruit puncture wounds <2 mm in diameter. Larger wounds were infected independently of immersion depth. Germination of spores of P. malorum was stimulated in water in which wounded fruit or fruit with epicuticular wax removed had been soaked, as compared to water in which whole fruit had been soaked.

Additional keywords: blue mold, Penicillium expansum, postharvest decay, Pyrus communis.