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.
Phaseolus vulgaris L. · Common bean
Harris Moran Seed Company (USA) (US)
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Spinacia oleracea L. · Spinach
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Beta vulgaris Sugar Beet Group · Sugar beet
SOYUZSEMSVEKLA
Hordeum vulgare L. · Barley
Nickerson International Research S.N.C.
Brassica napus var. napus · Rapeseed
Hodowla Roslin Strzelce Sp z.o.o. Grupa IHAR
Spinacia oleracea L. · Spinach
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Brassica oleracea L. (Brussels Sprouts Group) · Brussels sprouts
Hazera Seeds B.V.
Phaseolus vulgaris L. · Common bean
Pop Vriend Research B.V.
Beta vulgaris Sugar Beet Group · Sugar beet
Betaseed
Beta vulgaris Sugar Beet Group · Sugar beet
Betaseed
Solanum lycopersicum L. · Tomato
Seminis Vegetable Seeds
Lactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Poa pratensis L. · Kentucky bluegrass
JACKLIN SEED BY SIMPLOT
Beta vulgaris Garden Beet Group · Garden beet
BEJO ZADEN B.V.
Phaseolus vulgaris L. · Common bean
Seminis Vegetable Seeds
Agrostis stolonifera L. · Creeping bentgrass
Peak Plant Genetics, LLC & Rutgers, The State University of New Jersey
Brassica oleracea L. (Red Cabbage Group) · Red cabbage
BEJO ZADEN
Lolium perenne L. · Perennial ryegrass
Cydonia oblonga Mill. · Quince
Festuca trachyphylla (Hack.) Hack. · Hard fescue
Peak Plant Genetics
Festuca ovina L. · Sheep's fescue
PURE SEED TESTING
Hordeum vulgare L. · Barley
CREA- CENTRO DI RICERCA GENOMICA E BIOINFORMATICA (CREA-GB-FIO) / LIMAGRAIN ITALIA SPA