Diseases

Apple Scab

Malus domestica (Suckow) Borkh.

A fungal disease of apple trees caused by the ascomycete fungus Venturia inaequalis, affecting all aerial parts of the plant. The disease manifests as characteristic dark spots with a velvety coating, causing fruit deformation, premature leaf drop, and reduced crop quality.

In the reference 1 949 varieties crop Apple, where this is mentioned in the description.

The pathogen is the highly specialized parasite Venturia inaequalis. The fungus's life cycle includes a teleomorph, which overwinters in fallen leaves, and an anamorph, Fusicladium dendriticum, responsible for secondary infection during the growing season. The disease affects leaves, petioles, pedicels, and fruits, on which spots with an olive-black coating form, leading to cracking and tissue deformation.

Genetic resistance of varieties to the pathogen is associated with Rvi loci. The most well-known is the Rvi6 gene, previously designated as Vf; however, the high variability of the fungal population has led to the emergence of race 6 of the pathogen, which is capable of overcoming this resistance. To ensure long-term immunity, breeding programs are focused on pyramiding several resistance genes, such as Rvi2, Rvi3, Rvi5, and Rvi15.

General information about the subject — on the page Scab.

Sources8

Varieties of Apple 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.