Relationship of pink pigmentation in rose petals and Botrytis cinerea

Abstract

Pink pigmentation on rose (Rosa x hybrida) petals in the form of round spots or irregular-shaped discoloration has been associated with Botrytis cinerea infection, but scientific evidence has been lacking to support this hypothesis. The unfounded association between pink pigmentation and Botrytis blight has been sufficient to warrant rejection of international shipments during inspection at the ports of entry. The objective of this research was to evaluate the relationship between pink pigmentation symptoms on rose petals and B. cinerea infection. Four shipments of 'Vendela' and 'Brighton' roses were received from a commercial grower. Intact rose flowers and detached petals were assessed separately, and symptom development and Botrytis blight incidence were evaluated. In addition, tissue pieces with and without pink pigmentation were placed in culture media to determine the frequency of B. cinerea isolation. Results showed that Botrytis blight incidence in whole flowers and petals of cut roses with and without pink pigmentations was not significantly different. B. cinerea was not isolated more frequently from pink-pigmented tissue compared with tissues lacking pink pigmentation. These results show that pink pigmentation in the form of round spots or irregular-shaped discoloration along the petal margins is not associated with B. cinerea infections.