TAN06004
ActiveRosa L. · Rose
CHRISTIAN EVERS
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.
Rosa L. · Rose
CHRISTIAN EVERS
Rosa L. · Rose
CHRISTIAN EVERS
Vitis vinifera L. · Common grape vine
Bundesrepublik Deutschland vertreten durch Julius Kühn-Institut, Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement (INRAE)
Rosa L. · Rose
Hans Jurgen Evers
Verbena L. · Vervain
Ushio Sakazaki
Rosa L. · Rose
Hans-Juergen Evers
Rosa L. · Rose
UHL JÜRGEN
Phlox paniculata L. · Garden phlox
Verschoor Janus
Rosa L. · Rose
Hans-Juergen Evers
Rosa L. · Rose
CHRISTIAN EVERS
Verbena L. · Vervain
Syngenta Crop Protection AG
Rosa L. · Rose
CHRISTIAN EVERS
Avena sativa L. · Oat
Gesellschaft für goetheanistische Forschung e.V.
Digitalis xvalinii J. D. Arm.
MARTINUS WILLEM VAN DER SAR
Verbena L. · Vervain
Tomoya Misato
Coreopsis verticillata L. · Whorled tickseed
HARINI KORLIPARA
Rosa L. · Rose
CHRISTIAN EVERS
Petunia Juss. · Petunia
Ushio Sakazaki Suntory Flowers Limited
Echinacea purpurea (L.) Moench · Purple coneflower
van Noort Marco
Rosa L. · Rose
CHRISTIAN EVERS
Rosa L. · Rose
Hans Jurgen Evers
Humulus lupulus L. · Common hop
Roger D Jeske
Campsis x tagliabuana (Vis.) Rehder · Hybrid trumpet vine
Sakaue Koichi
Rosa L. · Rose
Hans-Juergen Evers