Interactions Among Fungi Causing Postharvest Decay of Pear. David Sugar, Oregon State University, Southern Oregon Experiment Station, Medford 97502. Kate Powers, Oregon State University, Southern Oregon Experiment Station, Medford 97502. Plant Dis. 70:1132-1134. Accepted for publication 10 April 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-1132.

Phialophora malorum and Cladosporium herbarum cause decay lesions on pears that are indistinguishable without isolating the causal fungus. Only P. malorum was isolated from lesions on benomyl-treated fruit sampled from a commercial packinghouse, whereas only C. herbarum was found in lesions on untreated fruit. When inoculated simultaneously into pear wounds, both fungi were recovered from decay lesions after 4 mo. When one fungus was inoculated before the other, the first inoculated was more frequently isolated in pure culture from lesions. Benomyl selectively controlled infection by C. herbarum without inhibiting infection by P. malorum. Wounds inoculated with Penicillium expansum and either Phialophora malorum or C. herbarum developed lesions from which only P. expansum was recovered, but sterile filtrate of Penicillium expansum did not inhibit infection by Phialophora malorum or C. herbarum.