CULTURAL CHARACTERISTICS OF SPHACELOMA AMPELINUM, CAUSAL PATHOGEN OF GRAPE ANTHRACNOSE ON DIFFERENT MEDIA

Abstract

Sphaceloma ampelinum, the causal pathogen of grape anthracnose, is the anamorph stage of Elsinoe ampelina. To evaluate its variability, isolates of S. ampelinum were collected from diseased plants from the northeastern, northern, eastern, and western regions of Thailand. The pathogen was isolated by a tissue transplanting method on water agar (WA) and the growing mycelium was subsequently transferred onto cereal agar (CA) and susceptible grape leaves to induce sporulation. Single conidial isolates were obtained and 19 representatives from all regions were cultured on potato dextrose agar (PDA), CA, corn cereal agar (CCA) and Job's tear corn cereal agar (JCCA) for cultural characterization. It was found that the different culture media affected growth, colony color, appearance, and formation of aerial mycelium. The best culture media for surface mycelium growth was CA, while PDA led to the highest aerial mycelium formation. In addition, CA induced the highest morphological variability among isolates. Variation of isolates appeared to be more pronounced among different regions than that within the same regions, except isolates from the eastern region. By using cultural characteristics alone, some isolates within the same region cannot be fully differentiated. These results suggest that diversity exists among isolates of S. ampelinum in Thailand, particularly those from different regions.