Diseases

Late blight

Phytophthora infestans

Late blight is a dangerous disease of solanaceous crops caused by an oomycete, which manifests as the appearance of spots on leaves, stems, and tubers. The development of the disease is triggered by high humidity and moderate temperatures, which can lead to significant crop losses.

Mentioned in descriptions 6 798 varieties reference book.

Affected plants develop dirty-brown spots, often accompanied by a whitish mold on the underside of the leaf, while elongated dark-brown spots appear on the stems. Tubers show hard, sunken brown spots, and the internal tissue exhibits a characteristic rust-brown discoloration upon cutting.

Epiphytotics develop under conditions of high air humidity around 90% and alternating warm days with cool nights. The presence of free moisture, such as dew or fog, is a critical factor for rapid spore germination, which allows the infection to spread across the field in 10–15 days.

In breeding, a distinction is made between specific vertical resistance, controlled by R-genes, and field horizontal resistance, which is considered more reliable due to its polygenic nature and ability to slow down pathogen development. Varieties are evaluated using a 9-point scale; however, the resistance level of the foliage does not always coincide with that of the tubers, requiring comprehensive analysis during variety testing.

Sources10

Breakdown by crop

Found in these crops

Potato 1 394 Tomato 276 Garden strawberry 124 Soybean 64 Bell pepper 56 Alfalfa 41 Red raspberry 34 Apple 26 Sweet chestnut 25 Citrus 22 Apple 19 Tomato 16

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.

Mariannka

Active

Solanum tuberosum L. · Potato

Vesa Velhartice a.s.

4 records

Lolita

Terminated

Solanum tuberosum L. · Potato

JOHANNA BERGER ^^^Stephan Berger

3 records

Marissard

Active

Castanea sativa Mill. · Sweet chestnut

INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE, FR

2 records

Luisa

Terminated

Solanum lycopersicum L. · Tomato

Hazera Genetics Ltd (IL)/Yissum Research dev of the Hebrew University of Jerusalem (IL)

2 records

Martiño

Active

Capsicum annuum L. · Bell pepper

JUNTA DE GALICIA (CIAM)

2 records

Marlhac

Active

Castanea sativa Mill. · Sweet chestnut

INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE, FR

2 records

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Diseases

Powdery mildew 33 570
Fusarium wilt and blight 29 887
Viral mosaic diseases 22 022
Downy mildew 16 384
Leaf spot diseases 15 926
Rust 14 859
Verticillium wilt 12 175
Scab 12 064

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.