IMMUNOFLUORESCENT STAINING OF SCLEROTINIA ASCOSPORES ON CANOLA PETALS

An immunofluorescence technique was used to study the distribution of ascospores of Sclerotinia sclerotiorum on field-collected canola petal s. Ascospores could be readily distinguished from the spores of other fungi and were sometimes observed in groups of more than 50. The quant itative relationships among mean numbers of ascospores per petal, the percentage of petals carrying ascospores as judged by immunofluorescen t staining, and the percentage of petals carrying viable ascospores as judged by a plating technique were studied by regression analysis. Th e multiple infection transformation successfully linearized the relati onships between percentage petals carrying ascospores and the mean num bers of ascospores per petal. About 30% of ascospores on the petals we re viable.