Diseases

Downy mildew

Peronosporaceae

Downy mildew is a dangerous plant disease caused by oomycetes under high humidity conditions. It manifests as a characteristic growth on the underside of leaves and spotting, which leads to rapid death of vegetative mass and yield reduction.

Mentioned in descriptions 16 384 varieties reference book.

Downy mildew is a group of diseases caused by specialized oomycetes. The disease manifests as the appearance of yellowish or brown angular spots on the upper side of the leaves, delimited by veins. On the underside of the leaf, under humid conditions, a characteristic grey-violet, white, or bluish fuzzy growth forms. Pathogen development leads to yellowing and drying of leaves, stunting of plants, and deformation of fruits, which, in the case of high pathogen aggressiveness, can lead to crop death in a short period.

Disease development depends directly on meteorological conditions and agronomic practices. The pathogen prefers a cool, humid environment, with critical risk factors being heavy dew, fog, prolonged rain, high air humidity, and crop density. Optimal conditions for infection include nighttime temperatures in the range of +13…+20°C and the presence of droplet moisture on the leaf surface for more than 6 hours.

Assessment of variety resistance during variety testing is based on phytopathological recording of the degree of leaf damage, specialized screening of collection samples, and molecular analysis methods using DNA markers to find genetic donors of resistance. In production, a distinction is made between genetically resistant varieties possessing specific Dm-genes and tolerant forms capable of maintaining yield under infection due to active vegetative mass formation. Since new pathogen races can overcome genetic resistance, varieties require regular monitoring and renewal.

Sources10

Breakdown by crop

Downy mildew of lettuce 2 007 Downy mildew of sunflower 905 Downy Mildew of Cucumber 394 Downy mildew of spinach 387 Downy Mildew of Pea 159 Downy Mildew (Peronospora) — Soybean 65 Downy Mildew of Hops 60 Downy mildew — Onion 59 Downy Mildew of Grapevine 58 Downy Mildew of Melon 48 Downy mildew — bulb onion 48 Downy mildew of radish 47 Downy mildew of basil 46 Downy mildew — broccoli 43 Downy Mildew of Grapevine 33 Downy mildew — New Guinea impatiens 32 Downy mildew of rapeseed 24 Downy mildew of zucchini 20 Downy mildew of wall rocket 19 Downy mildew — cauliflower 18 Downy mildew — lettuce 18 Downy mildew — head lettuce 18 Downy Mildew — Impatiens walleriana 18 Downy mildew — cabbage 17

Found in these crops

Lettuce 2 054 Grapevine 1 066 Sunflower 920 Common grape vine 514 Cucumber 414 Spinach 405 Pea 168 Common hop 77 Soybean 71 Onion 61 Onion 51 Melon 51

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.

SAKIMP033

Active

Impatiens New Guinea Group · New Guinea Impatiens

SATO CHIHIRO|MINEMURA SHINJI

4 records

SAKIMP061

Active

Impatiens New Guinea Group · New Guinea Impatiens

SATO CHIHIRO

4 records

SAKIMP039

Active

Impatiens New Guinea Group · New Guinea Impatiens

SATO CHIHIRO

4 records

Marroo Seedless

Active

Vitis L. · Grapevine

Commonwealth Scientific and Industrial Research Organisation

5 records

Itumone

Active

Vitis L. · Grapevine

Juan Carreño Manuel Tornel

4 records

Itasca

Active

Vitis L. · Grapevine

Peter Hempstad

4 records

Daytona

Active

Pisum sativum L. · Pea

Syngenta Participations AG

5 records

Bravo

Active

Humulus lupulus L. · Common hop

Roger D Jeske, Joe Brulotte

4 records

Apollo

Active

Humulus lupulus L. · Common hop

Roger D Jeske and Joe Brulotte

4 records

P64HH123

Active

Helianthus annuus L. · Sunflower

PIONEER OVERSEAS CORPORATION

SK UA

6 records

LG50609 SX

Active

Helianthus annuus L. · Sunflower

Remy ROUANET

SK UA

5 records

P64LE145

Active

Helianthus annuus L. · Sunflower

PIONEER OVERSEAS CORPORATION

ES UA

7 records

N4H205 E

Active

Helianthus annuus L. · Sunflower

NuSeed Americas

IT UA

6 records

Traveller

Active

Helianthus annuus L. · Sunflower

RAGT 2N S.A.S

IT UA

5 records

RGT Bellus

Active

Helianthus annuus L. · Sunflower

Sebastien Chatre

IT UA

5 records

LG50554 CLP

Active

Helianthus annuus L. · Sunflower

Remy ROUANET

SK UA

5 records

1018L CLP

Active

Helianthus annuus L. · Sunflower

Jean Pierre Dufourcq

IT UA

5 records

MAS 801A

Active

Helianthus annuus L. · Sunflower

MAS SEEDS

IT RO

4 records

Aiace SU

Active

Helianthus annuus L. · Sunflower

Maurizio Lottari

IT UA

5 records

Vulsini

Active

Lactuca sativa L. · Lettuce

Seminis Vegetable Seeds

5 records

Villana

Active

Vicia villosa Roth · Hairy vetch

SEMILLAS BATLLE, S.A.

ES SI

4 records

N4H337 E

Active

Helianthus annuus L. · Sunflower

NuSeed Americas

IT UA

4 records

N4h161 Cl

Active

Helianthus annuus L. · Sunflower

NuSeed Americas

FR IT

5 records

N4hm354

Active

Helianthus annuus L. · Sunflower

NUSEED EUROPE

IT RO

6 records

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Diseases

Powdery mildew 33 570
Fusarium wilt and blight 29 887
Viral mosaic diseases 22 022
Leaf spot diseases 15 926
Rust 14 859
Verticillium wilt 12 175
Scab 12 064
Grey mold 7 316

All terms →

Text source

This summary is compiled from the publications listed in the sources and verified by an editor. It contains no legally significant information; it provides agronomic context for registry data rather than the registry data itself.