Cronartiaceae

Cronartiaceae is a family of rust fungi in the order Pucciniales (Basidiomycota). The family includes several genera, the best known of which is Cronartium. Members are obligate plant pathogens that infect woody hosts, particularly conifers in the Pinaceae, and they often produce complex rust life cycles.

Life cycle and hosts: Many Cronartiaceae species are heteroecious, requiring two different host plants to complete their development. On the primary hosts, typically pines, the fungus forms pustules and produces spores that disseminate to secondary, alternating hosts, which are often dicot plants such as currants and gooseberries (Ribes) or related genera. Through this two-host cycle, they can cause diseases commonly referred to as blister rusts, cankers, or stem lesions.

Ecology and impact: Cronartiaceae fungi are usually restricted to regions with suitable climates and can have substantial economic impacts in forestry by slowing growth, causing branch and stem lesions, and increasing susceptibility to other stresses. White pine blister rust, caused by Cronartium ribicola, is among the best-known diseases attributed to this family and has been the subject of extensive management efforts in North America and Europe.

Distribution and taxonomy: The group has a temperate to boreal distribution in the Northern Hemisphere, with species described across North America, Europe, and Asia. Taxonomic revisions have refined Cronartiaceae, but Cronartium remains the central, best-characterized genus.

Notable species: Cronartium ribicola, the causative agent of white pine blister rust, exemplifies the agricultural and ecological significance of Cronartiaceae.