Sweet corn seedlings of the cultivar Jubilee were stunted and blighted in early spring 1985 plantings in Israel. Penicillium oxalicum was isolated from seedlings and from fungicide-treated seeds. Pathogenicity and seedborne transmission of the fungus were shown with both naturally infected and artificially inoculated seeds. Among seedlings grown from infected seed, the percentage with rotted mesocotyls was higher and the percentage with shoot height was lower at 15 and 20 C than at 25 and 30 C. Inhibition of seedling growth increased and the occurrence of wilt was more frequent as the inoculum concentration increased. Damage to seedlings from infected seeds was expressed more in sterile loess soil than in sand. The fungus lost its viability in seeds after storage at room temperature (20–25 C) for 12 mo. Methods for assessing seed infection and transmission by seed are described.