Abstract
A. japonica is a seed-borne pathogen of plants in the Brassicaceae. No sexual state is known for the fungus, and identification based on conidial and cultural morphology is difficult. The production of chlamydospores, structures that should allow it to survive in soil or plant debris, does distinguish it from similar species. It is known to occur in certain regions on all continents, but is generally a minor pathogen compared to other species on the same hosts. Its major impact consists of reduced germination of contaminated seeds and disease and death of seedlings. It is not listed as being of concern by phytosanitary agencies, but imported seed lots can be and are rejected due to its presence, because once introduced, it can persist and then spread by means of airborne conidia.