Use of Interactions of Cultures to Distinguish Monilinia laxa from M. fructicola. R. M. Sonoda, Associate Professor, Institute of Food and Agricultural Sciences, University of Florida, Agricultural Research Center, Fort Pierce 33450. J. M. Ogawa, Professor, and B. T. Manji, Staff Research Associate IV, Department of Plant Pathology, University of California, Davis 95616. Plant Dis. 66:325-326. Accepted for publication 12 June 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-325.

Monilinia laxa and M. fructicola were distinguished by characteristic interactions between isolates when grown on oatmeal agar. Distinct black lines formed between Monilinia fructicola and M. laxa colonies within 10 days and profuse microconidia by 20 days of incubation. Light, double lines were visible between some of the M. laxa isolates after 15–20 days of incubation. The formation of distinct lines within 10 days was used as one of the criteria that a benomyl-resistant Monilinia isolate with scalloped margins on potato-dextrose agar was M. fructicola.

Keyword(s): brown rot.