Diseases

Gray Mold of Poinsettia

Euphorbia pulcherrima Willd. ex Klotzsch

A fungal disease caused by Botrytis cinerea that affects all above-ground parts of the plant. Bracts and cyathia are particularly susceptible, with damage leading to browning and premature abscission.

In the reference 8 varieties crop Poinsettia, where this is mentioned in the description.

The causal agent of gray mold on poinsettia is the fungus Botrytis cinerea Pers. The infection manifests on leaves and stems as brown, water-soaked spots, on the surface of which a characteristic fuzzy, grayish-brown layer of conidial sporulation forms under high humidity.

The most vulnerable parts of the poinsettia are the flowers and bracts, where the development of the disease causes browning and tissue abscission. In severe cases, the pathogen penetrates the stem or crown, causing the wilting of individual shoots and the death of the entire plant.

In poinsettia breeding practice, there are no specific resistance genes to this pathogen. Breeding efforts are primarily conducted through selection for an increased level of tolerance, as monogenic resistance to Botrytis cinerea has not been identified.

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

Sources8

Varieties of Poinsettia 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.