VIEW ARTICLE

Detection and Characterization of Cercospora citrullina Isolates That Sporulate Readily in Culture. M. J. Goode, Professor, Departments of Plant Pathology and Horticulture, University of Arkansas, Fayetteville 72701; G. R. Brown, Research Assistant, Departments of Plant Pathology and Horticulture, University of Arkansas, Fayetteville 72701. Phytopathology 60:1502-1503. Accepted for publication 7 May 1970. DOI: 10.1094/Phyto-60-1502.

Cercospora citrullina, like most species of Cercospora, has not produced conidia in artificial culture. Attempts to induce sporulation by subjecting mycelial isolates to various cultural and nutritional variables were unsuccessful. The genetic variability of C. citrullina was exploited by examining a large number of isolates which had been obtained by streaking conidia from lesions on watermelon, Citrullis vulgaris. Two pathogenic isolates were obtained that sporulated readily on potato-dextrose agar (PDA) under ordinary room conditions. The sporulating and pathogenicity characters remained stable throughout a 2-year study. Conidia could be produced in 72-96 hr on fresh PDA whether initiated from conidia or mycelia from stock cultures. Loss of the ability to sporulate in culture by Cercospora isolates may be explained on the basis of heterokaryosis.