Occurrence of leaf spot caused by Cristulariella depraedans on Acer ginnala

Abstract

The occurrence of previously unknown leaf spots on Amur maples ( Acer ginnala) has consistently been noticed during disease surveys in Korea since 2004. The symptoms included circular or irregular leaf spots that were greyish-green to brownish-grey in colour, which led to leaf senescence and premature defoliation. The morphological and cultural characteristics confirmed the identity of the causal agent as Cristulariella depraedans. This identification was supported by sequence comparisons based on ITS and LSU regions. The monospore isolate proved to be pathogenic when inoculated to the host plant under artificial conditions. This is the first report of C. depraedans infecting Amur maples in the world.