Prior to the federal quarantine No. 37, which was a general code governing the importation of plant material into the United States, many millions of small white pines were imported from Europe and planted in this country. It was on these trees that white pine blister rust, a disease of five-leaf pines, was accidentally brought to America. For a time this deadly forest tree disease, white pine blister rust, threatened to wipe out our valuable white pine forests, but simple and effective methods have been developed to bring this rust under control.
Kouba, Theodore F.
"White Pine Blister Rust,"
Ames Forester: Vol. 21
, Article 6.
Available at: https://lib.dr.iastate.edu/amesforester/vol21/iss1/6