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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.

Monarda L. · Bee balm

Oudshoorn Hubertus Gerardus

3 records

Rubus L. subg. Rubus · Blackberry

Driscoll Strawberry Associates Inc.

6 records

Phlox paniculata L. · Garden phlox

Geerlings-Meyer

4 records

Rosa L. · Rose

Société Nouvelle Pépinières et Roseraies Georges Delbard S.A.S.

3 records

Hylotelephium telephium (L.) H. Ohba · Orpine

Janet N. Egger

4 records

Lagerstroemia L. · Crape Myrtle

Hansen Hans A

3 records

Rosa L. · Rose

Société Nouvelle Pépinières et Roseraies Georges Delbard S.A.S.

3 records

Hybrid between Astilbe x arendsii and Astilbe japonica

van de Meer Hans

3 records

Ajuga reptans L. · Bugle

Tristram Mike|Arundel, West Sussex BN18 0LL, GB

3 records

Bolton

Active

Hordeum vulgare L. · Barley

Claus Einfeldt

4 records

Tiarella L. · Foamflower

TERRA NOVA NURSERIES INC

3 records

Monarda didyma L. · Bee balm

Trees Scott

4 records

Vicia faba L. · Broad bean

Semillas Fitó S.A.

4 records

CIVRH621

Active

Fragaria x ananassa Duchesne ex Rozier · Garden strawberry

Michelangelo Leis^^^Alessio Martinelli

4 records

Lagerstroemia indica L. · Crape myrtle

Fleming's Flower Fields Inc.

3 records

Ribes nigrum L. · Blackcurrant

V. Kopan c/o Institute of Horticulture Research Centre

6 records

CIVRH612

Active

Fragaria x ananassa Duchesne ex Rozier · Garden strawberry

Michelangelo Leis^^^Alessio Martinelli

4 records

CIVN251

Active

Fragaria x ananassa Duchesne ex Rozier · Garden strawberry

Alessio Martinelli^^^Michelangelo Leis

4 records

Cambrena

Active

Triticum aestivum L. · Bread wheat

Dario Fossati Agroscope

5 records

Coreopsis L. · Tickseed

Winner Blair

3 records

APPOTTPI

Active

Phlox paniculata L. · Garden phlox

van den Haak Jelle

4 records

Anemone hupehensis Lemoine · Japanese anemone

Yoshihiro Kanazawa

3 records

Phlox paniculata L. · Garden phlox

Kievit Christa

3 records

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