Diseases
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.
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.
Solanum tuberosum L. · Potato
RADDATZ (DE)
Solanum tuberosum L. · Potato
IRPT.ZAMARTE
Solanum lycopersicum L. · Tomato
Syngenta Crop Protection AG
Solanum tuberosum L. · Potato
Kweekbedrijf-Zpc (NL)
Gerbera L. · Gerbera
ROZENOORD| Rozenoord PVBA
Solanum lycopersicum L. · Tomato
Harris Moran Seed (US)
Allium cepa L. · Onion
Martin Slot, John Pieter Schipper,
Solanum lycopersicum L. · Tomato
Pro-Veg Seeds Ltd. Unit N Peek House, Dales Manor Business Park
Solanum tuberosum L. · Potato
UNION TEMPORAL EMPRESAS
Solanum lycopersicum L. · Tomato
Les Graines Caillard Sa (FR)
Solanum tuberosum L. · Potato
Kweekbedrijf-Zpc (NL)
Gerbera jamesonii Bolus ex Hook. f. · Barberton daisy
FLORIST DE KWAKEL BV (NL)
Streptocarpus x hybridus Voss · Cape primrose
Gerhard Fleischle
Lavandula angustifolia Mill. · English lavender
Radoslav Georgiev
Prunus persica (L.) Batsch · Peach
HANSEN CARL J.
Solanum tuberosum L. · Potato
MEYER WILHELM| Wilhelm Meyer in Fa. Golden Geest Kartoffel Erzeuger-gesellschaft mbH
Solanum lycopersicum L. · Tomato
Nunhems BV (NL)
Solanum tuberosum L. · Potato
Kmetijski inštitut Slovenije (SI)
Solanum tuberosum L. · Potato
Kartoffelzucht Böhm GmbH & Co. KG
Solanum tuberosum L. · Potato
Przedsiębiorstwo Państwowe Stacja Hodowli Roślin Lotyń
Solanum lycopersicum L. · Tomato
Vreugdenhil Breeding & Seeds B.V.
Allium porrum L. · Leek
Rijk Zwaan B.V.
Solanum lycopersicum L. · Tomato
Syngenta Crop Protection AG
Solanum tuberosum L. · Potato
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