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.
Fagopyrum esculentum Moench · Buckwheat
Shevel` Vitalii Ihorevych, Shevel` Ihor Vasyl`ovych, Dykyi Viktor Vasyl`ovych,
Lactuca sativa L. · Lettuce
RIJK ZWAAN Z.Z. B.V.
Triticum aestivum L. subsp. aestivum · Bread wheat
R2n S.A.S. (Societe RAGT 2N)
Cucumis sativus L. · Cucumber
Enza Zaden Beheer B.V.
Vitis L. · Grapevine
INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE, FR
Malus domestica (Suckow) Borkh. · Apple
Gospodarstwo Szkółkarskie Andrzej i Szymon Nowakowscy
Poa pratensis L. · Kentucky bluegrass
PURE SEED TESTING
Cucumis melo L. · Melon
KWS VEGETABLES B.V.
Rosa L. · Rose
Klymenko Zinaida Kostiantynivna
Vitis L. · Grapevine
INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE, FR
Ribes nigrum L. · Blackcurrant
Estonian University of Life Sciences
Solanum lycopersicum L. · Tomato
Kees Reinink
Malus domestica (Suckow) Borkh. · Apple
Information not available - Contact NL authorities
Triticum aestivum L. subsp. aestivum · Bread wheat
BORRIES| W. von Borries-Eckendorf GmbH & Co. Kommanditgesellschaft
Daucus carota L. · Carrot
Hari Besels
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Niwa Hodowla Roślin Jagodowych sp. z o.o.
Cucumis sativus L. · Cucumber
Kees Reinink
Prunus persica (L.) Batsch · Peach
IVASCU ANTONIA
Cucumis sativus L. · Cucumber
Kees Reinink
Cucumis sativus L. · Cucumber
Ger Bimsdeboer
Vitis vinifera L. · Common grape vine
Rubeniia Revazi Klymentiovych
Cucumis melo L. · Melon
RIJK ZWAAN Z.Z. B.V.
Triticum durum Desf. · Durum wheat
Eurodur
Cucumis sativus L. · Cucumber
RIJK ZWAAN Zaadteelt en Zaadhandel B.V.