Diseases

Apple Root Rots

Malus domestica (Suckow) Borkh.

A complex of diseases affecting the apple root system, caused by oomycetes of the genus Phytophthora, fungi of the genera Fusarium and Armillaria, as well as bacteria involved in apple replant disease (ARD).

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

The primary pathogen of collar and root rot is Phytophthora cactorum; P. syringae, P. cambivora, and P. citricola also exhibit pathogenicity. Fusarium infections are incited by F. proliferatum, F. oxysporum, F. solani, F. sporotrichioides, F. avenaceum, F. sambucinum, and F. poae. Armillaria mellea causes shoestring root rot, while members of the genus Streptomyces play a significant role in the development of apple replant disease.

Symptoms include stunted growth, premature leaf drop, chlorosis, and sudden spring wilt of trees. In the case of Phytophthora rot, dark brown cankers appear on the root collar, and the cambium beneath the bark turns orange-brown. The root system gradually darkens, decays, and dies, which is particularly pronounced under conditions of excessive moisture and poor soil aeration.

A specific classification into races and pathotypes for these pathogens on apple trees has practically not been developed. Resistance issues are addressed through the selection of rootstocks, as cultivars exhibit varying degrees of susceptibility to pathogens. The use of genetic resistance, similar to that against scab or powdery mildew, is not applied in breeding programs against root rots.

General information about the subject — on the page Root rots.

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.