In Calabria (S. Italy) Slerotium cepivorum is the most important disease of red onion ‘Tropea’ (Agosteo & Davino, 2009). Leaves of plants infected with the white rot pathogen show yellowing, leaf dieback and wilting. A semi-watery decay of the bulb scales results. Roots also rot and the plant can be easily pulled from the ground. Associated with the rot is a fluffy white mycelium, which develops around the base of the bulb with numerous small spherical sclerotia.