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Diseases

Leaf spot 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.

Sources10

Breakdown by crop

Found in these crops

Varieties that feature this in their description

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.

Xirlero

Active

Eriobotrya japonica (Thunb.) Lindl. · Loquat

Cooperativa Agrícola de Callosa d'en Sarrià - Cooperativa Valenciana

1 record

Tango

Application submitted

Populus x canadensis Moench · Carolina poplar

Laura Rosso^^^Franco Picco^^^Pier Mario Chiarabaglio^^^Massimo Gennaro^^^Sara Bergante^^^Andrea Carra^^^Achille Giorcelli^^^Gianni Allegro^^^Giuseppe Nervo^^^Lorenzo Vietto

1 record

WALBRISTAR

Terminated

Yucca gloriosa L.

Albert Timothy Alan Crowther

1 record

Fragaria x ananassa Duchesne ex Rozier · Garden strawberry

Walther Faedi^^^Gianluca Baruzzi^^^Pierluigi Lucchi

2 records

Hybrids between Echinacea purpurea (L.) Moench and Echinacea paradoxa (Norton) Britton

HARINI KORLIPARA

1 record

Tnsp

Terminated

Hybrids between Echinacea purpurea (L.) Moench and Echinacea paradoxa (Norton) Britton

HARINI KORLIPARA

1 record

Sunpa 796

Application submitted

Mandevilla x amabilis (Backh. & Backh. f.) Dress · Alice du Pont mandevilla

Masahiro Yamada

1 record

Fragaria x ananassa Duchesne ex Rozier · Garden strawberry

ABZ Aardbeien uit Zaad Holding B.V.

2 records

Sunbird

Terminated

Hybrids between Echinacea purpurea (L.) Moench and Echinacea paradoxa (Norton) Britton

HARINI KORLIPARA

1 record

Sir Lancelot

Terminated

Echinacea purpurea (L.) Moench · Purple coneflower

ARIE BLOM

1 record

Sheila

Withdrawn

Hydrangea macrophylla (Thunb.) Ser. · Bigleaf hydrangea

Kwekerij Sidaco B.V.

1 record

Lavandula L. · Lavender

Koning Smit IPR S.A.

1 record

Hybrids between Echinacea purpurea (L.) Moench and Echinacea paradoxa (Norton) Britton

HARINI KORLIPARA

1 record

Secret Pride

Terminated

Hybrids between Echinacea purpurea (L.) Moench and Echinacea paradoxa (Norton) Britton

HARINI KORLIPARA

1 record

Sierra Gold

Terminated

Solanum tuberosum L. · Potato

DR. GREIGHTON MILLER J. JNR.

1 record

Summer Sunset

Withdrawn

Trachelospermum asiaticum Nakai · Asiatic jasmine

Kromhout B.V.

1 record

Royal Mona

Application submitted

Prunus persica (L.) Batsch · Peach

Zaiger's Inc. Genetics

1 record

Satin Nights

Terminated

Hybrids between Echinacea purpurea (L.) Moench and Echinacea paradoxa (Norton) Britton

HARINI KORLIPARA

1 record

Allium cepa L. var. cepa · Onion

The Sweet Onion company Ltd.

1 record

Echinacea Moench. · Coneflower

HARINI KORLIPARA

1 record

Hydrangea aspera Buch.-Ham. ex D. Don · Rough-leaved hydrangea

Maurice C. Foster

1 record

Rondo

Withdrawn

Chaenomeles japonica (Thunb.) Lindl. ex Spach · Japanese quince

Kimmo Rumpunen^^^Darius Kviklys^^^Silvija Ruisa

1 record

Rhododendron

Application submitted

Rhododendron catawbiense Michx. · catawba rhododendron

TYAS VERBRUGGE

1 record

Purple Leia

Withdrawn

Veronica spicata L. · Spiked speedwell

Hans A. Hansen

1 record

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