noun
also white-pine rust
: a disease of 5-leaved pine (as Swiss pine or various No. American white pines) that is prob. of Asiatic origin but widely established in Europe and No. America, is caused by a rust fungus ( Cronartium ribicola ) with a complex life cycle requiring a plant of the genus Ribes (as a currant or gooseberry) as alternate host, and is marked by destructive invasion of the bark and underlying tissues with swelling and girdling of the infected branch or tree leading to death of the parts above the lesion — compare felt rust