SMPOTW
ActivePhysocarpus opulifolius (L.) Maxim. · Ninebark
Wood Timothy D
Diseases
Powdery mildew of ninebark
Physocarpus opulifolius (L.) Maxim.
A fungal disease of ninebark caused by the obligate pathogen Podosphaera physocarpi, manifested as a powdery coating, shoot deformation, and premature defoliation.
In the reference 3 varieties crop Ninebark, where this is mentioned in the description.
The causative agent of powdery mildew in Physocarpus opulifolius is the highly specialized obligate parasite Podosphaera physocarpi. The disease affects both young and old leaves, as well as stems, inflorescences, and fruit clusters, covering them with a characteristic white coating consisting of fungal mycelium and conidia.
The infection causes significant deformation: leaves curl and become stunted, while affected stems thicken, often leading to the formation of "witches' brooms" and subsequent dieback of shoots. Severe infection triggers premature leaf drop, which significantly reduces the ornamental value of the plant.
Intraspecific diversity among ninebark cultivars is characterized by varying degrees of susceptibility to the pathogen. Studies show that cultivars such as 'Nanus' and 'Seward' exhibit relative resistance to the infection compared to more susceptible varieties, such as 'Monlo'.
General information about the subject — on the page Powdery mildew.
Varieties of Ninebark 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.