Alternaria alternata causes petal blight and flower drop in harvested Geraldton waxflower

Six isolates of Alternaria alternata were tested and shown to be pathogenic on detached flowers of Geraldton waxflower cv. Alba. The fungus caused petal blight and abscission of the pedicel from inoculated flowers. This finding strengthens the hypothesis that fungal infection of Geraldton waxflower flowers commonly leads to premature flower drop. Furthermore, it shows that, in addition to Botrytis cinerea, which has been shown previously to cause flower abscission, A. alternata can also cause flower abscission