Diseases
Lactuca sativa L. var. capitata L.
A fungal disease caused by the obligate oomycete Bremia lactucae, characterized by the appearance of chlorotic spots on leaves, followed by the formation of sporulation and tissue necrosis.
In the reference 18 varieties crop Head lettuce, where this is mentioned in the description.
The pathogen Bremia lactucae is characterized by high genetic variability, forming numerous races capable of overcoming varietal resistance. Symptoms manifest as irregular chlorotic spots on the upper leaf surface, delimited by veins, and a characteristic grayish or purple growth on the underside, consisting of the pathogen's conidiophores. Under severe infection, the tissue becomes necrotic, plants show stunted growth, and lose their marketability.
Breeding for resistance is based on the use of Dm (Downy mildew) genes introduced from wild Lactuca species. Varietal resistance is designated by the Bl index, indicating the spectrum of races (e.g., BI:16–40EU). The IBEB international board regularly updates race standards, which must be considered when selecting seed material, as high resistance (HR) or intermediate resistance (IR) to older pathotypes does not guarantee protection against new, constantly evolving strains.
General information about the subject — on the page Downy mildew.
Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.
Lactuca sativa L. var. capitata L. · Head lettuce
TORSEED - Przedsiebiorstwo Nasiennictwa Ogrodniczego i Szkolkarstwa S.A.
Lactuca sativa L. var. capitata L. · Head lettuce
PLANTICO HODOWLA I NASIENNICTWO OGRODNICZE ZIELONKI SP. Z O.O.
Lactuca sativa L. var. capitata L. · Head lettuce
Ger Beemsterboer
Lactuca sativa L. var. capitata L. · Head lettuce
PLANTICO HODOWLA I NASIENNICTWO OGRODNICZE ZIELONKI SP. Z O.O.
Lactuca sativa L. var. capitata L. · Head lettuce
Kees Reinink
Lactuca sativa L. var. capitata L. · Head lettuce
Rijk Zwaan B.V.
Lactuca sativa L. var. capitata L. · Head lettuce
Kees Reinink
Lactuca sativa L. var. capitata L. · Head lettuce
PLANTICO HODOWLA I NASIENNICTWO OGRODNICZE ZIELONKI SP. Z O.O.
Lactuca sativa L. var. capitata L. · Head lettuce
PLANTICO HODOWLA I NASIENNICTWO OGRODNICZE ZIELONKI SP. Z O.O.
Lactuca sativa L. var. capitata L. · Head lettuce
Przedsiębiorstwo Nasiennictwa Ogrodniczego i Szkółkarstwa Spółka Akcyjna w upadłości likwidacyjnej \Instytut Ogrodnictwa - Państwowy Instytut Badawczy
Lactuca sativa L. var. capitata L. · Head lettuce
Ger Beemsterboer
Lactuca sativa L. var. capitata L. · Head lettuce
CORA SEEDS S.R.L
Lactuca sativa L. var. capitata L. · Head lettuce
PLANTICO HODOWLA I NASIENNICTWO OGRODNICZE ZIELONKI SP. Z O.O.
Lactuca sativa L. var. capitata L. · Head lettuce
HORTAG SEED CO.
Lactuca sativa L. var. capitata L. · Head lettuce
Nunhems B.V.
Lactuca sativa L. var. capitata L. · Head lettuce
Lactuca sativa L. var. capitata L. · Head lettuce
Lactuca sativa L. var. capitata L. · Head lettuce