Jounia
ActiveCucumis sativus L. · Cucumber
Nunhems, B.V.
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
Nunhems, B.V.
Pisum sativum L. · Pea
W BROTHERTON SEED CO INC
Cucurbita pepo L. · Field pumpkin
Syngenta Seeds B.V.
Triticum aestivum L. · Bread wheat
SAATZUCHT JOSEF BREUN GMBH and CO.KG
Cucumis sativus L. · Cucumber
ZKI, H
Poa pratensis L. · Kentucky bluegrass
JACKLIN SEED
Triticum durum Desf. · Durum wheat
GYULA ZALABAI / TIBOR CSEMY
Rosa L. · Rose
STICHTING DLO-CENTRUM VOOR PLANTENVEREDELINGS-EN
Vitis vinifera L. · Common grape vine
Manuel Tornell, Juan Carreno, Investigacion y Tecnologia de Uva de Mesa
Linum usitatissimum L. · Common flax
Linéa Semences de Lin G.I.E.
Pisum sativum L. · Pea
MARIBO SEED INT. APS
Triticum aestivum L. · Bread wheat
Danko Hodowla Roslin Sp. Zo.o., Pl- 64-000 Koscian
Malus Mill. · Apple
Luby, Jim|St. Paul, MN / Bedford, David S.|Delano, MN
x Triticosecale Wittm. ex A. Camus · Triticale
INAKTIV HegeSaat GmbH & Co. KG Herrn Dr. Elmar Weißmann
Hordeum vulgare L. · Barley
SECOBRA RECHERCHES S.A.S
Triticum aestivum L. subsp. spelta (L.) Thell. · Spelt
F. Weilenmann Agroscope / Hans Winzeler Agroscope / Michael Winzeler Agroscope / W. Saurer Agroscope
Pisum sativum L. · Pea
CRITES SEEDS
Hydrangea macrophylla (Thunb.) Ser. · Bigleaf hydrangea
Jacobus Gerardus Hofstede|Wilhelmus Jacobus Gerardus Hofstede
Pisum sativum L. · Pea
ROGERS SEED CO
Vitis vinifera L. · Common grape vine
Juan Carreño Espín^^^Manuel Tornel Martinez
Triticum aestivum L. subsp. spelta (L.) Thell. · Spelt
Peter Franck^^^Norbert Starck
Brassica napus L. var. napobrassica (L.) Rchb. · Rutabaga
JAMES HUTTON LTD
Cucumis sativus L. · Cucumber
NUNHEMS
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.