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.
Lolium perenne L. · Perennial ryegrass
Pickseed USA, Inc. & Rutgers, The State University of New Jersey
Daucus carota L. · Carrot
BEJO ZADEN
Hordeum vulgare L. · Barley
Syngenta Seeds, UK
Lolium perenne L. · Perennial ryegrass
Rutgers, The State University of New Jersey
Lolium perenne L. · Perennial ryegrass
PEAK PLANTS GENETICS LLC
Spinacia oleracea L. · Spinach
PHILIPS SIMONS
Spinacia oleracea L. · Spinach
Philip Simons
Festuca arundinacea Schreb. · Tall fescue
Lebanon Seaboard Corporation (US)
Rosa L. · Rose
HANS JURGEN EVERS (T)
Malus domestica (Suckow) Borkh. · Apple
KVITSCHAL Marcus Vinicius (BR)/CRESTANI HAWERROTH Maraisa (BR)/DENARDI Frederico (BR)
Lolium perenne L. · Perennial ryegrass
Pickseed USA, Inc. & Rutgers, The State University of New Jersey
Malus domestica (Suckow) Borkh. · Apple
KVITSCHAL Marcus Vinicius (BR)/CRESTANI HAWERROTH Maraisa (BR)/DENARDI Frederico (BR)
Festuca ovina L. · Sheep's fescue
Steve Reid
Phaseolus vulgaris L. · Common bean
W BROTHERTON SEED CO INC
Lolium perenne L. · Perennial ryegrass
Pickseed USA, Inc. & Rutgers, The State University of New Jersey
Festuca rubra L. · Red fescue
JACKLIN SEED
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Michelangelo Leis^^^Alessio Martinelli
Medicago sativa L. · Alfalfa
NEW SOUTH WALES DEP.OF AGRIC.
Coreopsis grandiflora Hogg ex Sweet · Large-flowered tickseed
Tristram, David Ralph|Walberton Nursey, Yapton Lane, Walberton, Arundel, West Sussex,, England, BN18 0AS
Cercis canadensis L. · Eastern redbud
Werner Dennis James|Raleigh, NC, US / Snelling Layne Karlton|Cary, NC, US
Zea mays L. · Maize
PIONEER HI-BRED INTERNATIONAL
Malus domestica (Suckow) Borkh. · Apple
Frederico Denardi c/o EPAGRI
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Fresh Forward Holding B.V., 6851 ET Huissen
Lachenalia Jacq. f. ex Murr. · Cape Cowslip
ricultural Research Council