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Diseases

Powdery mildew

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.

Sources10

Breakdown by crop

Found in these crops

Varieties that feature this in their description

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.

Rosa L. · Rose

Poulsen Roser A/S

5 records

Fragaria x ananassa Duchesne ex Rozier · Garden strawberry

WORLDWIDE

4 records

Syringa L. · Lilac

van Nijnatten Andre Franciscus

4 records

Odessa

Active

Spiraea japonica L. f. · Japanese meadowsweet

Herman Geers

5 records

Rosa L. · Rose

PHILIPPE VEYS

4 records

Malus domestica (Suckow) Borkh. · Apple

Luby, James / University of Minnesota

5 records

Rosa L. · Rose

MEILLAND ALAIN ANTOINE

4 records

MINDOUV5

Active

Hibiscus syriacus L. · Rose of Sharon

Pineau Patrick

5 records

Rosa L. · Rose

Reinhard Noack

4 records

Rosa L. · Rose

Meilland International

5 records

Rosa L. · Rose

Meilland International

4 records

Rosa L. · Rose

Meilland Alain A.

5 records

Rosa L. · Rose

Meilland Alain A.

4 records

Rosa L. · Rose

MEILLAND ALAIN ANTOINE

4 records

Rosa L. · Rose

Meilland Alain A.|Antibes, FR

4 records

Malus domestica (Suckow) Borkh. · Apple

5 records

Oenothera lindheimeri (Engelm. & A. Gray) W. L. Wagner & Hoch · Lindheimer's beeblossom

Graham N. Brown

4 records

Mandarin

Active

Lonicera L. · Honeysuckle

University of British Columbia

4 records

Matan

Active

Prunus dulcis (Mill.) D. A. Webb · Almond

The State of Israel Ministry of Agriculture & Rural Development Agricultural Research Organization

6 records

Agastache Clayt. ex Gronov. · Giant hyssop

Janet N. Egger

5 records

Rosa L. · Rose

Wilhelm Kordes,Tim-Hermann Kordes,Margarita Kordes

4 records

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