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.
Cucumis sativus L. · Cucumber
Enza Zaden Beheer B.V.
Begonia L. · Begonia
Rohde-Rieger, Margarete
Solanum lycopersicum L. · Tomato
STEFANO CARLI
Festuca arundinacea Schreb. · Tall fescue
University of Missouri
Lolium multiflorum Lam. var. westerwoldicum Wittm. · Westerwolds Ryegrass
RAGT 2N S.A.S
Hordeum vulgare L. · Barley
SEMILLAS BATLLE, S.A.
Avena sativa L. · Oat
SELGEN A.S
Beta vulgaris Sugar Beet Group · Sugar beet
SESVanderhave NV
Beta vulgaris Fodder Beet Group · Mangelwurzel
Malopolska Hodowla Roslin Spolka z o.o.
Brassica napus var. napus · Rapeseed
LIMAGRAIN EUROPE
Beta vulgaris Sugar Beet Group · Sugar beet
Khoremans Stefan
Populus L. · Poplar
Institute for Forestry and Nature Research (NL)
Solanum lycopersicum L. · Tomato
HAZERA GENETICS
Hordeum vulgare L. · Barley
Limagrain Central Europe Cereals s.r.o.
Capsicum annuum L. · Bell pepper
Yordan Todorov, Stoyka Masheva, Velichka Todorova, Lozina Georgieva
Beta vulgaris Sugar Beet Group · Sugar beet
KUTNOWSKA HODOWLA BURAKA CUKROWEGO Sp.z o.o.
Brassica napus var. napus · Rapeseed
Reinhard Hemker
Trifolium pratense L. · Red clover
PAJBJERG A/S
Brassica napus L. · Rapeseed
LIMAGRAIN EUROPE
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V. (NL)
Beta vulgaris Fodder Beet Group · Mangelwurzel
KWS SAAT SE & CO.KGAA
Beta vulgaris Sugar Beet Group · Sugar beet
KUTNOWSKA HODOWLA BURAKA CUKROWEGO Sp.z o.o.
Prunus cerasus L. · Sour cherry
Lolium multiflorum Lam. ssp. italicum (A. Br.) Volkart · Italian ryegrass
RAGT 2n, FR