any of several diseases of pines that are caused by rust fungi (genus Cronartium) in the aecial stage and that affect the sapwood and inner bark and produce blisters externally
blister rust
noun(blister rust)
a destructive disease of white pine caused by a rust fungus (Cronartium ribicola) that passes part of its complex life cycle on currant or gooseberry bushes; also : this fungus