Diseases

St. John's Wort Rust

Hypericum L.

A fungal disease of St. John's wort caused by the autoecious pathogen Melampsora hypericorum. It manifests as colored spots and pustules on leaves, leading to tissue necrosis and a reduction in the quality of plant raw materials.

In the reference 17 varieties crop St. John's wort, where this is mentioned in the description.

The causal agent of St. John's wort rust is the fungus Melampsora hypericorum, which is characterized by a narrow specialization on members of the genus Hypericum. This pathogen belongs to autoecious species, allowing it to complete its full life cycle without alternating hosts and to cause recurring infections of plants within a population.

Symptoms of the disease are characterized by the appearance of yellow, orange, or reddish-brown spots on the underside of leaves, as well as the formation of characteristic pustules containing orange spore powder. Severe infection causes yellowing, premature leaf drop, and tissue necrosis, which significantly diminishes the ornamental properties and the value of the harvest.

Data regarding the division of the pathogen into pathotypes, as well as the presence of mapped resistance genes in St. John's wort breeding, are absent. Given the lack of specific genetic markers, breeding efforts for the crop are focused on increasing the general tolerance of plants to the infection.

General information about the subject — on the page Rust.

Sources8

Varieties of St. John's wort 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.