The infestation of tomato seed by Fusarium oxysporum f.sp. radicis‐lycopersici

The infestation of seed by Fusarium oxysporum f.sp. radicis‐lycopersici occurred at rates of 0‐1 to 0‐01 % in fruit on stem‐infected plants. Direct infection of fruit in the flower or young developing fruit stage resulted in a grayish‐brown lesion on the stylar end of the fruit or mummification. F. oxysporum f.sp. radicis‐lycopersici was isolated from all seeds in such fruit. Picked fruit inoculated on the stem scar also became infected but 96 h after inoculation of the fruit, the seed was not infested or infected. The contact of clean seed with hands that had previously handled F. oxysporum f.sp. radicis‐lycoperisid‐infesied sawdust resulted in a high level of seed infestation. The fungus survived on seed sent across Canada and stored for up to 12 weeks. Treatment with NaOCl or 0·1 N HCl did not completely disinfest infested seed.