Comparative Studies of Cryptosporiopsis Curvispora and C. Perennans. I. Morphology and Pathogenic Behavior

ABSTRACT

Macroconidia of Cryptosporiopsis curvispora, cause of apple anthracnose, consistently displayed high curvature while those of C. perennans, cause of perennial canker, displayed low curvature when representative isolates of both species were separately and simultaneously inoculated into apple branches. Highly curved macroconidia were occasionally produced on potato dextrose agar by the former species but never by the latter. Conidia produced on V8-oatmeal agar differed significantly between species in regard to lengths, widths and correlation coefficients between lengths and widths. No species differences in conidial wall topography were seen with scanning electron microscopy. Only C. curvispora produced abundant pulvinate conidiomata as cultures aged on potato dextrose agar; only C. perennans produced synnemata without expanded apices on V8-oatmeal agar. On lesions of inoculated apple fruit C. perennans produced significantly more conidia than C. curvispora, but the species did not differ with regard to appressorium formation or lesion size on fruit or canker extension on branches.

Key Words:

• apple anthracnose
• bull's-eye rot
• Cryptosporiopsis curvispora
• C. perennans
• Melanconiales
• perennial canker