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.
Trifolium pratense L. · Red clover
DLF Seeds A-S, DK
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Hordeum vulgare L. · Barley
Graminor AS, N-2322 Ridabu
Solanum lycopersicum L. · Tomato
Bernardus van den Bosch
Beta vulgaris Sugar Beet Group · Sugar beet
PETER MADLAINA, HAUER DIETRICH
Cucurbita pepo L. · Field pumpkin
Syngenta Seeds B.V.
Cucumis sativus L. · Cucumber
Zakład Ogrodniczy Przyborów sp. z o.o. \Instytut Ogrodnictwa - Państwowy Instytut Badawczy
Cucumis melo L. · Melon
Ralf Kuijpers
Beta vulgaris Sugar Beet Group · Sugar beet
Betaseed
Triticum aestivum L. · Bread wheat
PZO Pflanzenzucht Oberlimpurg, DE
Citrullus lanatus (Thunb.) Matsum. & Nakai · Watermelon
Syngenta Crop Protection AG
Brassica napus L. · Rapeseed
Meyer, Jan
Cucumis melo L. · Melon
Syngenta Crop Protection AG, CH
Triticum aestivum L. · Bread wheat
KWS Lochow
Trifolium pratense L. · Red clover
Przedsiebiorstwo Hodowlano-Nasienne sp. z o.o.
Cucurbita pepo L. · Field pumpkin
Syngenta Seeds BV (NL)
Rosa L. · Rose
Hans Jurgens Evers (DE)
Lolium multiflorum Lam. · Italian ryegrass
DLF SEEDS A/S
Fragaria L. · Strawberry
Reinhold von Sengbusch
Rosa L. · Rose
Rosen Tantau KG
Malus Mill. · Apple
Murawski en Fischer
Triticum aestivum L. subsp. aestivum · Bread wheat
W. von Borries-Eckendorf GmbH & Co.KG
Triticum aestivum L. · Bread wheat
KWS Lochow
Malus Mill. · Apple
FISCHER MANFRED / MURAWSKI HEINZ / SCHMADLAK JOHANN