La Diva
ActiveCucumis sativus L. · Cucumber
Johnny's Selected Seeds
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.
Cucumis sativus L. · Cucumber
Johnny's Selected Seeds
Triticum aestivum L. · Bread wheat
KWS MOMONT RECHERCHE SARL, FR
Avena sativa L. · Oat
KWS MOMONT RECHERCHE SARL, FR
Triticum aestivum L. · Bread wheat
KWS Lochow
Avena sativa L. · Oat
BERTHOLD BAUER
Capsicum annuum L. · Bell pepper
Syngenta Seeds B.V.
Avena sativa L. · Oat
KWS MOMONT RECHERCHE SARL, FR
Lactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis melo L. · Melon
Nunhems B.V.
Lactuca sativa L. · Lettuce
RIJK ZWAAN ZAADTEELT EN ZAADHANDEL BV
x Triticosecale Wittm. ex A. Camus · Triticale
Elmar A. Weissmann
Hordeum vulgare L. · Barley
Danko Hodowla Roslin Sp.z.o.o.
Triticum aestivum L. · Bread wheat
Danko Hodowla Roslin Sp.z.o.o.
Triticum aestivum L. · Bread wheat
SEMILLAS BATLLE, S.A.
Cucumis melo L. · Melon
Enza Zaden Beheer B.V.
Pisum sativum L. · Pea
BROTHERTON SEED COMPANY INC
Avena sativa L. · Oat
Selgen
Rosa L. · Rose
Wilhem Kordes
Hordeum vulgare L. · Barley
DE Agrártudományi Centrum Kutató Központja, Karcag
Pisum sativum L. · Pea
Danko Hodowla Roslin Sp.z.o.o.
Symphoricarpos Duham. · Snowberry
Leyssen
Hordeum vulgare L. · Barley
Danko Hodowla Roslin Sp.z.o.o.
Rosa L. · Rose
David Austin Roses
Cucumis sativus L. · Cucumber
Ikasido Global Group B.V