C. ribicola

Cronartium ribicola is a species of rust fungus in the family Cronartiaceae that causes the disease white pine blister rust.

Like many other rusts, C. ribicola is heteroecious, meaning it requires two host species to complete its life cycle that includes five spore stages. The aecial hosts are white pines (Pinus subgenus Strobus, family Pinaceae) and the telial hosts include wild and introduced currants and gooseberries (Ribes, family Grossulariaceae), and two genera of the Orobanchaceae, Pedicularis and Castilleja. Species of both telial and aecial hosts have varying levels of resistance or immunity to infection. This rust is believed to be native to Asia or Europe and was subsequently introduced to North America. Some European and Asian white pines (e.g. Macedonian Pine, Swiss Pine, Blue Pine) are mostly resistant to the disease, having co-evolved with the pathogen.