Diseases

Grey Mold of Lettuce

Lactuca sativa L.

A fungal disease of lettuce caused by the pathogen Botrytis cinerea, manifested by water-soaked spots, fluffy grey mold, and soft rot of the root neck.

In the reference 11 varieties crop Lettuce, where this is mentioned in the description.

Infection of lettuce typically begins on the lower leaves in contact with the soil or at sites of mechanical damage. Initial symptoms appear as water-soaked spots that eventually turn grayish-brown or yellow-orange; under high humidity, these become covered with a characteristic 'fluffy' grey sporulation layer. The pathogen is capable of penetrating the root neck, triggering the development of soft wet rot, which leads to rapid wilting and plant death, while black flat sclerotia may form within the tissues.

Botrytis cinerea can persist in lettuce tissues in a latent form for long periods, emerging only when favorable conditions arise. Specific races of the pathogen strictly linked to lettuce cultivars have not been identified, and resistance in the crop is quantitative and polygenic in nature. Currently, no generally accepted resistance genes similar to the resistance factors for downy mildew exist, therefore breeding programs searching for QTL loci rely on the use of wild lettuce relatives.

General information about the subject — on the page Grey mold.

Sources8

Varieties of Lettuce mentioned in the description

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.