Diseases
Leaf spot diseases are a group of fungal, bacterial, or viral disorders manifesting as tissue necrosis in the form of spots of various shapes and colors. Pathogen development leads to a reduction in photosynthetic leaf area, tissue deformation, and significant yield losses.
Mentioned in descriptions 15 926 varieties reference book.
Leaf spot diseases represent a collective group of conditions caused by fungi, bacteria, or viruses. The primary diagnostic symptom is the formation of spots of various colors—brown, yellow, black, or gray—on the leaf blades, ranging from small dots to extensive necrotic lesions with or without margins. Infection often originates in the lower leaf canopy and, if allowed to develop, leads to premature defoliation and overall plant weakening.
Disease progression depends on a combination of favorable meteorological factors, such as moderately warm temperatures and high humidity, as well as the agrotechnical background. Improper crop rotation and the retention of crop residues in fields contribute to the accumulation of inoculum and intensive infection of crops in subsequent seasons. The severity of disease manifestation correlates directly with pathogen aggressiveness and the degree of cultivar susceptibility, which can lead to a 20–30% or greater reduction in crop productivity.
Cultivar resistance to leaf spots is a genetically determined ability to maintain productivity under disease pressure. It can be specific, targeting particular pathogen races, or non-specific polygenic, providing complex protection. Resistance mechanisms include physical barriers, such as waxy coatings, and biochemical responses. During variety testing, resistance is evaluated under natural and artificial inoculation conditions using scoring scales to record the degree of necrosis and pathogen development.
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.
Apium graveolens L. var. dulce (Mill.) Pers. · Celery
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Brassica napus L. · Rapeseed
DEUTSCHE SAATVEREDELUNG AG
Malus domestica (Suckow) Borkh. · Apple
Hordeum vulgare L. · Barley
Claus Einfeldt
Capsicum annuum L. · Bell pepper
Seminis Vegetable Seeds
Zea mays L. · Maize
Syngenta Crop Protection,CH
Triticum aestivum L. subsp. spelta (L.) Thell. · Spelt
Hodowla Roslin Smolice Sp.z o.o Grupa IHAR
Spinacia oleracea L. · Spinach
RIJK ZWAAN Zaadteelt en Zaadhandel B.V.
Poa pratensis L. · Kentucky bluegrass
TOP GREEN SAS
Triticum aestivum L. · Bread wheat
Sejet Planteforaedling I,S
Brassica napus var. napus · Rapeseed
RAGT 2n, FR
Beta vulgaris Sugar Beet Group · Sugar beet
MARIBO SEED INT. APS
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel BV (NL)
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Hordeum vulgare L. · Barley
Nordic Seed A/S
Beta vulgaris Garden Beet Group · Garden beet
Nunhems Germany GmbH
Hordeum vulgare L. · Barley
Syngenta Participations AG
Beta vulgaris Garden Beet Group · Garden beet
Sakata Vegetables Europe, F
Beta vulgaris Sugar Beet Group · Sugar beet
Strube D&S GMBH
Triticum aestivum L. · Bread wheat
Wiersum Plantbreeding B.V.
Solanum lycopersicum L. · Tomato
Bejo Zaden B.V.
Phleum pratense L. · Timothy grass
Feldsaaten Freudenberger G.m.b.H. & Co Kommanditgesellschaft
Delphinium L. · Larkspur
LEGRO| R.A.H. Legro
Daucus carota L. · Carrot
Ger Beemsterboer