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
Normarc, Inc.
Beta vulgaris Sugar Beet Group · Sugar beet
Sesvanderhave, B
Lolium perenne L. · Perennial ryegrass
Rutgers, the State University of New Jersey and Novel AG, Inc.
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Daucus carota L. · Carrot
BEJO ZADEN
Hordeum vulgare L. · Barley
Syngenta UK Ltd
Poa pratensis L. · Kentucky bluegrass
PURE SEED TESTING
Beta vulgaris Garden Beet Group · Garden beet
BEJO ZADEN
Cucurbita pepo L. · Field pumpkin
Ralf Kuijpers
Hordeum vulgare L. · Barley
SAATZUCHT STRENG-ENGELEN GMBH&CO. KG
Hordeum vulgare L. · Barley
Syngenta Seeds, F
Festuca rubra L. · Red fescue
Limagrain Genetics Grandes Cultures SA (FR)
Beta vulgaris Sugar Beet Group · Sugar beet
Miroslaw Lakomy
Festuca arundinacea Schreb. · Tall fescue
DLF Seeds A/S
Hordeum vulgare L. · Barley
Graminor AS, N-2322 Ridabu
Helianthus annuus L. · Sunflower
MAY AGRO SEED COPR.
Phaseolus vulgaris L. · Common bean
Rob Gehin
Hordeum vulgare L. · Barley
Carlsberg Research Laboratory
Festuca rubra L. · Red fescue
Euro Grass Breeding GmbH Co. KG
Cydonia oblonga Mill. · Quince
Beta vulgaris Garden Beet Group · Garden beet
Ger Beemsterboer
Beta vulgaris Garden Beet Group · Garden beet
Ger Beemsterboer
Daucus carota L. · Carrot
Robert Prieur
Lolium perenne L. · Perennial ryegrass
Innoseeds B.V. (NL)