SMNSHSO
ActiveSyringa x hyacinthiflora Rehder
Wood Timothy D
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.
Syringa x hyacinthiflora Rehder
Wood Timothy D
Helenium autumnale L. · Common sneezeweed
ARIE BLOM
Pulmonaria L. · Lungwort
TERRA NOVA NURSERIES INC
Malus domestica (Suckow) Borkh. · Apple
RUP «BRESTSKAYA OBLASTNAYA SELSKOXOZYAJSTVENNAYA OPYTNAYA STANCZIYA NAN BELARUSI»
Geranium pratense L. · Meadow crane's-bill
Warrington Helen
Rosa L. · Rose
De Ruiter Intellectual Property B.V.
Hydrangea serrata (Thunb.) Ser. var. serrata · Tea-of-heaven
Wood Timothy D
Hydrangea macrophylla (Thunb.) Ser. · Bigleaf hydrangea
Takanori Kawaguchi
Paeonia L. · Peony
Smith Donald R.
Paeonia L. · Peony
Smith Donald R.
Zinnia x marylandica D. M. Spooner et al.
Sakata Seed Corporation (SCC)
Zinnia x marylandica D. M. Spooner et al.
Sakata Seed Corporation (SCC)
Coreopsis L. · Tickseed
IT Saul Plants LLC
Phlox paniculata L. · Garden phlox
Van Gaalen Irenaeus Antonius Maria
Verbascum L. · Mullein
Korlipara Harini|Canby, OR, US
Populus x canadensis Moench · Carolina poplar
Giuseppe Nervo^^^Gianni Allegro^^^Gianni Facciotto^^^Achille Giorcelli^^^Lorenzo Vietto^^^Gaetano Castro^^^Stefano Bisoffi^^^Maria de los Angeles Gras
Monarda L. · Bee balm
Hubertus Gerardus Oudshoorn
Zinnia x marylandica D. M. Spooner et al.
Sakata Seed Corporation (SCC)
Zinnia x marylandica D. M. Spooner et al.
Sakata Ornamentals Europe A/S
Petunia Juss. · Petunia
Ui Akinobu
Vitis vinifera L. · Common grape vine
Gabriele Di Gaspero^^^Guido Cipriani^^^Michele Morgante^^^Enrico Peterlunger^^^Simone Diego Castellarin^^^Raffaele Testolin
Ribes L. · Currants
THE KENT INCORPORATED SOCIETY
Phlox x procumbens Lehm.
Akiko Kitahara
Phlox L. · Phlox
A. VERSCHOOR HORTICULTURE IMPORT-EXPORT B.V