Black Rot of Cranberry Caused by Strasseria oxycocci. M. R. Schwarz, Research Assistant, Department of Plant Pathology, University of Wisconsin, Madison 53706. D. M. Boone, Professor, Department of Plant Pathology, University of Wisconsin, Madison 53706. Plant Dis. 67:31-32. Accepted for publication 4 May 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-31.

An examination of cranberries from New Jersey revealed that Strasseria oxycocci can cause a storage rot indistinguishable from black rot caused by Ceuthospora lunata, S. oxycocci was isolated from 30% and C. lunata from 70% of black-rotted cranberries selected from New Jersey samples. The two fungi (S. oxycocci and C. lunata) were never isolated from the same cranberry. The pathogenicity of S. oxycocci was assessed by inoculating sound Searles cranberries with single-spore isolates. Symptoms identical to black rot caused by C. lunata developed within 3 wk. The berry tissues softened and turned black in 90% of the berries incubated at 12 C and 55% of the berries at 24 C. Only S. oxycocci was reisolated from these inoculated cranberries with black rot symptoms.