Esprit
ActivePisum sativum L. · Pea
Van Waveren, D
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.
Pisum sativum L. · Pea
Van Waveren, D
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Silvertand, B. C. H. J.
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SYNGENTA SEEDS B.V.
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Pisum sativum L. · Pea
CRITES SEED INC
Malus domestica (Suckow) Borkh. · Apple
HM the King in Right of Canada a.r.b the Minister of Agriculture and Agri-Food
Coreopsis grandiflora Hogg ex Sweet · Large-flowered tickseed
Tristram, David Ralph|Walberton Nursey, Yapton Lane, Walberton, Arundel, West Sussex,, England, BN18 0AS
Rosa L. · Rose
HANS JURGEN EVERS (T)
Vitis L. · Grapevine
VI¥A DEL DEPARTAMENTO DE AGRICULTURA DE LOS EEUU DE ACA. EN EL SERVICIO DE INV. AGRICOLA
Cercis canadensis L. · Eastern redbud
Werner Dennis James|Raleigh, NC, US / Snelling Layne Karlton|Cary, NC, US
Rosa L. · Rose
William RADLER
Rosa L. · Rose
Peter Joseph James
Rosa L. · Rose
Meilland Alain A.|Antibes, FR
Rosa L. · Rose
Meilland Alain A.|Antibes, FR
Rosa L. · Rose
Meilland International
Rosa L. · Rose
Meilland International
Rosa L. · Rose
Wilhelm Kordes,Tim-Hermann Kordes,Margarita Kordes
Rosa L. · Rose
Wilhelm-Alexander Kordes, Tim-Hermann Kordes, John-Vincent Kordes
Rosa L. · Rose
Wilhelm Kordes,Tim-Hermann Kordes,Margarita Kordes
Vitis vinifera L. · Common grape vine
David W. Cain, PhD.
Vitis vinifera L. · Common grape vine
NO DECLARADOS