1. any of several diseases of pines caused by rust fungi of the genus Cronartium and marked by destructive invasion of bark and sapwood and producing blisters externally • Syn: white-pine rust, white pine blister rust • Hypernyms: rust 2. fungus causing white pine blister rust and having a complex life cycle requiring a plant of genus Ribes as alternate host • Syn: Cronartium ribicola • Hypernyms: rust, rust fungus • Member Holonyms: Cronartium, genus Cronartium