Shell disease of rock oyster Crassostrea cucuilata

Abstract

ABSTRACT: A shell disease of Crassostrea cucullata Born. (rock oyster), caused by the fungus Ostracoblabe implexa Bornet et Flahault, is reported from Indian waters for the first time. The fungus causes small dark flecks on the inner surface of the valves. Decalcification of shells revealed that the fungal hyphae grew within the shell matrix. The fungus was cultured in yeast extract peptone seawater medium. Experimental infection of oyster shells in the laboratory was achieved by incubating the valves with fungal mycelia in seawater. Uninfected pieces of shell, placed in direct contact with infected oyster shells, became infected within 2 wk.