SUMMARYIn a simple, routine test developed to detect viableSeptoriaspp. in samples of celery seed, seed washings are inoculated on to celery seedlings. Viable infection was detected in fifty‐four samples between 1960 and 1966. The method can be used to detect viable infection on one seed in several thousand.Spore exudation during ‘blotter’ tests was shown to be associated with lesion production both in the seedling inoculation test and in growing‐on tests. A high incidence of saprophytic fungi indicates that seed has not been treated but a low incidence does not mean that the sample is