Diseases

Grey Mold of Rose

Rosa L.

A fungal disease of roses caused by Botrytis cinerea, which develops primarily under high humidity conditions and affects flowers, buds, and shoots.

In the reference 17 varieties crop Rose, where this is mentioned in the description.

The causal agent of the disease is the necrotrophic fungus Botrytis cinerea (teleomorph Botryotinia fuckeliana), which survives as mycelium and sclerotia on plant debris. There are no specific races or pathotypes of the fungus adapted exclusively to roses, and the infection mechanisms are common to a number of plants.

Symptoms on flowers appear as small whitish or purple spots on the petals. Buds turn brown, fail to open, and become covered with a smoky-grey sporulation layer. Sunken dark spots occur on the shoots, which can lead to girdling and dieback of the stem from the top down.

The fungus mainly attacks weakened, senescing, or damaged tissues, although it can infect healthy parts of the plant under high humidity. There is no information on specific resistance genes to the pathogen in roses, and cultivar susceptibility is determined by their morphological characteristics.

General information about the subject — on the page Grey mold.

Sources8

Varieties of Rose mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.