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.
Spinacia oleracea L. · Spinach
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Poa pratensis L. · Kentucky bluegrass
PURE SEED TESTING
Hordeum vulgare L. · Barley
Sejet Planteforaedling I,S
Festuca arundinacea Schreb. · Tall fescue
PROF. DR. DIRK REHEUL /DR. IR. MATHIAS COUGNON
Hordeum vulgare L. · Barley
Dr. Jörg Großer in Fa. KWS LOCHOW GMBH - Zuchtstation Wetze -
Solanum lycopersicum L. · Tomato
Enza Zaden Beheer B.V.
Cucumis melo L. · Melon
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Citrus sinensis (L.) Osbeck · Sweet orange
Linda Grobler
Hordeum vulgare L. · Barley
Landwirtschaftliche Fachschule Edelhof Saatzucht
Hordeum vulgare L. · Barley
Saatzucht Streng-Engelen GmbH & Co. KG^^^Pflanzenzucht SaKa GmbH & Co. KG
Festuca trachyphylla (Hack.) Hack. · Hard fescue
Lebanon Seaboard Corporation (US)
Glycine max (L.) Merr. · Soybean
Poljoprivredni Institut Osijek, HR
Spinacia oleracea L. · Spinach
Syngenta Crop Protection AG
Cucumis sativus L. · Cucumber
Monsanto Vegetable IP Management B.V.
Brassica napus var. napus · Rapeseed
KWS MOMONT RECHERCHE S.A.R.L
hybrids between Solanum lycopersicum L. and S. habrochaites S. Knapp & D.M. Spooner
Syngenta Seeds B.V.
Spinacia oleracea L. · Spinach
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Beta vulgaris Sugar Beet Group · Sugar beet
Sesvanderhave, B
Hydrangea macrophylla (Thunb.) Ser. · Bigleaf hydrangea
Shiobara Shigeo
Brassica napus var. napus · Rapeseed
Monsanto Technology LLC, US
Solanum lycopersicum L. · Tomato
Sakata Vegetables Europe S.A.S
Festuca arundinacea Schreb. · Tall fescue
JACKLIN SEED
Lolium perenne L. · Perennial ryegrass
DLF USA, Inc. and Rutgers, The State University of New Jersey
Brassica oleracea L. (Cauliflower Group) · Cauliflower
BEJO ZADEN