Rhythm and Blues
ActiveAstilbe Buch.-Ham. ex D. Don · False goat's beard
Verduin Harry G. J.|Heemskerk, NL
Diseases
Erysiphales
Powdery mildew is a fungal disease manifesting as a white web-like coating on plant organs, leading to tissue necrosis, fruit deformation, and significant crop losses.
Mentioned in descriptions 33 570 varieties reference book.
Powdery mildew is caused by ectoparasitic fungi of the order Erysiphales, which develop primarily on the surface of leaves, shoots, and fruits. The initial white web-like coating eventually densifies into "powdery" cushions, upon which fungal fruiting bodies may form as dark spots. As a result of the infection, tissues turn yellow and become necrotic, fruits may crack, and leaves drop prematurely.
The intensity of disease development depends on a complex of factors: high relative humidity, moderate temperatures, the presence of dense canopy, and excessive nitrogen nutrition. Risks increase with alternating dry and wet weather. The harmfulness of the disease is expressed in a reduction of the leaf assimilation area, deterioration of crop quality, and a decrease in the general winter hardiness of crops.
Assessment of variety resistance is conducted under field conditions at various stages of vegetation, most often during the full heading phase. To classify the degree of infection, scoring systems or intensity scales in percentages are used, where varieties with up to 10% infection are considered highly resistant (R), 11 to 40% as moderately resistant (M), and more than 41% as susceptible (S). Variety resistance is ensured by genetic mechanisms that prevent colonization by the pathogen or limit the development of its mycelium.
Selection based on the description text, not official resistance ratings: such data is not available in registers. Mention indicates that the trait is discussed in the variety's sources; see the variety's profile for details on what is specifically stated.
Astilbe Buch.-Ham. ex D. Don · False goat's beard
Verduin Harry G. J.|Heemskerk, NL
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Graminor AS, N-2322 Ridabu
Zinnia x marylandica D. M. Spooner et al.
Sakata Seed Corporation
Helenium autumnale L. · Common sneezeweed
Holtmaat Henricus Maria Joseph
Rosa L. · Rose
Poulsen Roser A/S
Agastache Clayt. ex Gronov. · Giant hyssop
Hansen Hans A
Triticum aestivum L. · Bread wheat
RAGT 2N S.A.S
x Triticosecale Wittm. ex A. Camus · Triticale
Aldo Fossati Agroscope
Triticum aestivum L. · Bread wheat
Lantmannen SW Seed AB, SE-268 81 Svalof
Anemone hupehensis Lemoine · Japanese anemone
Yoshihiro Kanazawa
Triticum aestivum L. · Bread wheat
LIMAGRAIN EUROPE
Pulmonaria L. · Lungwort
TERRA NOVA NURSERIES INC
Hydrangea L. · Hydrangea
RAMPP JUNGPFLANZEN GMBH & CO. VERTRIEBS KG
Triticum aestivum L. · Bread wheat
Graminor AS, N-2322 Ridabu
hybrids between Prunus davidiana, Prunus dulcis and Prunus persica
Pinochet Jorge|Barcelona, ES
Penstemon Schmidel. · Beard Tongue
Lubbe Remy
Rosa L. · Rose
Poulsen Roser A/S
Zinnia L. · Zinnia
Sakata Seed Corporation (SCC)
Phlox paniculata L. · Garden phlox
Verschoor Jan|Haarlem, NL
Rosa L. · Rose
Poulsen Roser A/S
Rosa L. · Rose
Poulsen Roser A/S
Coreopsis L. · Tickseed
Probst Darrell R
Hydrangea L. · Hydrangea
PREISIG WALTER
Agastache Clayt. ex Gronov. · Giant hyssop
Hansen Hans A