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.
Lagerstroemia indica L. · Crape myrtle
Pepinieres DESMARTIS SA (FR)
Capsicum annuum L. · Bell pepper
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Rosa L. · Rose
Pepinieres & Roseraies Dorieux GAEC (FR)
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
SC Darbonne (FR)
Cucurbita moschata Duchesne · Butternut squash
Bidai Ol`ha Valentynivna, Polivoda Lidiia Ivanivna, Zavertaliuk Volodymyr Filimonovych, Kolesnyk Ivan Ivanovych,
Helianthus annuus L. · Sunflower
Tovarystvo z obmezhenoiu vidpovidalnistiu «TK ART-AHRO»
Triticum aestivum L. · Bread wheat
Viichenko Ol`ha Ivanivna, Vasylenko Taisiia Fedorivna, Radchenko Mykola Kyrylovych, Radchenko Ihor Mykolaiovych,
Rosa L. · Rose
Pepinieres et Roseraies Georges Delbard| FR
Rosa L. · Rose
Societe Nouvelle des Pepinieres & Roseraies Georges DELBARD (FR)
Ribes nigrum L. · Blackcurrant
Institut Sadiwnictwa Ukrainska Akademija Agrarnich Nauk Volodymyr Kopan
Rosa L. · Rose
Societe Nouvelle des Pepinieres & Roseraies Georges DELBARD (FR)
Solanum lycopersicum L. · Tomato
Bayer Holland B.V.
Rosa L. · Rose
Pepinieres et Roseraies Georges Delbard| FR
Rosa L. · Rose
Mark Gergely / Mark Gergelyne
Rosa L. · Rose
Dominique Croix (FR)
x Triticosecale Wittm. ex A. Camus · Triticale
NORDSAAT| NORDSAAT Saatzuchtgesellschaft mbH
Malus domestica (Suckow) Borkh. · Apple
Information not available - Contact NL authorities
Vitis vinifera L. · Common grape vine
INCONNU (FR)
Vitis vinifera L. · Common grape vine
FONTAINE-TRANCHANT Maurice (FR)
Cucumis sativus L. · Cucumber
QUEDLING| Saatzucht Quedlinburg GmbH
Ribes uva-crispa L. · Gooseberry
Instytut Ogrodnictwa - Państwowy Instytut Badawczy
Triticum durum Desf. · Durum wheat
FARMERS MARKETING CORPORA
Malus domestica (Suckow) Borkh. · Apple
Sempra Praha a.s., CZ
Vitis vinifera L. · Common grape vine
INCONNU (FR)