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.
x Triticosecale Wittm. ex A. Camus · Triticale
Danko Hodowla Roslin Sp.z.o.o.
Hordeum vulgare L. · Barley
Apsovsementi, I
Hordeum vulgare L. · Barley
Apsovsementi S.p.A., CREA-GB
Hordeum vulgare L. · Barley
TIMULE GENOVEFA YaZEPOVNA / STRUMLE ZEL'MA IVANOVNA / VIKSNE VELTA KARLOVNA / KUDE RAISA MIHAJLOVNA
Solanum lycopersicum L. · Tomato
Michael Edwin Kuenh
Zea mays L. subsp. mays (Popcorn Group) · Popcorn
CROOKHAM COMPANY
Solanum lycopersicum L. · Tomato
SAKATA SEED AMERICA INC US
Poa pratensis L. · Kentucky bluegrass
SEED RESEARCH OF OREGON
Lolium perenne L. · Perennial ryegrass
SEED RESEARCH OF OREGON
Lolium perenne L. · Perennial ryegrass
SEED RESEARCH OF OREGON
Lolium perenne L. · Perennial ryegrass
SEED RESEARCH OF OREGON
Lolium perenne L. · Perennial ryegrass
TURF MERCHANTS
Solanum lycopersicum L. · Tomato
HEINZSEED
Nicotiana tabacum L. · Tobacco
NOVARTIS SEEDS
Veronica L. · Speedwell
TULLY NURSERIES
Geranium wallichianum D. Don ex Sweet · Wallich's geranium
SYLVIA MORROW
Nyssa sylvatica Marshall · Black tupelo
Warren Keith S.
Lagerstroemia L. · Crape Myrtle
Kardos Joshua H.
Citrus xtangelo J. W. Ingram & H. E. Moore · Tangelo
Jude W. Grosser^^^William S. Castle^^^Frederick G. Gmitter Jr.
Papaver orientale L. · Oriental poppy
Oudshoorn Hubertus Gerardus
Begonia masoniana Irmsch. · Iron cross begonia
Smit Obed
Lagerstroemia L. · Crape Myrtle
Michael A. Dirr^^^Rhonda Helvick^^^Mark Griffith^^^Oren McBee^^^Jeff Beasley
Lagerstroemia L. · Crape Myrtle
Michael Dirr
Zea mays L. subsp. mays (Popcorn Group) · Popcorn
Crookham Company (US)