VIEW ARTICLE

Ecology and Epidemiology

Sources of Inoculum of Phialophora malorum, Causal Agent of Side Rot of Pear. 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, OR. Phytopathology 82:735-738. Accepted for publication 16 April 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/Phyto-82-735.

Phialophora malorum was found in pear orchard soil over a 2-yr period. P. malorum was not a primary colonizer of fallen fruit on orchard soil, but propagule numbers increased subsequent to fruit decay by other organisms. Cankers developed when P. malorum was inoculated into injured bark of pear trees but not when spore suspensions were held in contact with uninjured bark. Cankers were nonperennial, and P. malorum was not recovered from cankered tissue after one season. The fungus was isolated in washings of bark of pear trees, but dispersal of inoculum from artificially infested bark to other areas of bark on the same trees was not observed.