Diseases

Rust of Populus × canadensis

Populus x canadensis Moench

A fungal disease caused by pathogens of the genus Melampsora, primarily affecting the foliage of Canadian poplar. It manifests as yellow pustules on the underside of leaves, leading to premature defoliation and reduced wood increment.

In the reference 15 varieties crop Carolina poplar, where this is mentioned in the description.

The pathogens causing rust on Populus × canadensis are the fungal species Melampsora larici-populina, Melampsora medusae, and their interspecific hybrid Melampsora medusae-populina. Infection typically occurs in spring, with characteristic symptoms in the form of orange-yellow pustules becoming widespread by mid-summer.

Severe infection is accompanied by necrotic spots, curling, and premature leaf drop. These pathogens are characterized by the presence of various pathotypes with differing degrees of virulence, which can lead to a decrease in the resistance of specific clones upon the emergence of new aggressive fungal races.

The crop's resistance to rust is predominantly polygenic and is described as a quantitative trait associated with the use of specific parental pairs. Breeding for pathogen resistance is complicated by the high dynamics of fungal races, making field trials of clones for susceptibility to local fungal populations the primary assessment method.

General information about the subject — on the page Rust.

Sources8

Varieties of Carolina poplar 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.