San Marcos
WithdrawnCucumis melo L. · Melon
Sakata Vegetables Europe SARL (FR)
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 melo L. · Melon
Sakata Vegetables Europe SARL (FR)
Cucumis melo L. · Melon
Syngenta Seeds B.V.
Cucumis melo L. · Melon
Syngenta Seeds BV (NL)
Cucumis melo L. · Melon
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Vitis vinifera L. · Common grape vine
Valentin Blattner
Cucumis melo L. · Melon
De Ruiter Zonen (HR)
Cucumis melo L. · Melon
Nunhems B.V./Laboratioire ASL S.N.C.
Triticum aestivum L. · Bread wheat
University of Georgia Research Foundation
Vitis L. · Grapevine
GUIDO CIPRIANI / ENRICO PETERLUNGER / GABRIELE DI GASPERO / MICHELE MORGANTE / SIMONE DIEGO CASTELLARIN / RAFFAELE TESTOLIN
Cucumis melo L. · Melon
HM.Clause S.A.S.
Triticum aestivum L. · Bread wheat
ERHARD EBMEYER
Phaseolus vulgaris L. · Common bean
Krakowska Hodowla i Nasiennictwo Ogrodnicze POLAN sp. z o.o.
Malus domestica (Suckow) Borkh. · Apple
Sempra Praha a.s., CZ
Solanum lycopersicum L. · Tomato
GOLDEN VALLEY SEED
Capsicum annuum L. · Bell pepper
Clause Semences SA (FR)
Hordeum vulgare L. · Barley
Posviatenko Natalia Stepanivna, Tsykalenko Mykola Ivanovych, Romanenko Vasyl` Ivanovych,
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Capsicum annuum L. · Bell pepper
Enza Zaden Beheer B.V.
Lactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
Cucumis sativus L. · Cucumber
Seminis Vegetable Seeds
Cucumis melo L. · Melon
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Rosa L. · Rose
KORDES' SOEHNE| W. Kordes' Soehne Rosenschulen GmbH & Co KG
Cucumis sativus L. · Cucumber
Unbekannt, Keine Angabe
Cucurbita pepo L. · Field pumpkin
UNITED GENETICS SEEDS CO