White pine blister rust, Cronartium ribicola J. C. Fischer, requires a pine (Pinus L.) and a Ribes L. as obligate alternate hosts. The center of diversity for this rust is east of the Ural Mountains, where the organism evolved with P. cembra L and R. nigrum var. sibericum L over several million years. Susceptible Pinus strobus L from North America was imported into England in 1710 and was transplanted throughout eastern Europe. In 1865, rust was first reported on these introduced pines in Eastonia. In the late 1800s, the white pine nursery industry continued to develop in Europe, but was declining in the United States. American foresters began importing white pines from Europe. Rust was found on cultivated currants in New York in 1906 and U.S. inspectors began examining for the disease. In 1910, infected white pines were imported from France into Vancouver, British Columbia; in 1911, infected pines were found in New Hampshire, Vermont, Massachusetts, Connecticut, Pennsylvania, Indiana, Ohio, Ontario, and Quebec. Additional rust-infected imported pines were found in nurseries in Wisconsin in 1913, and Minnesota in 1914. Rust spread to native pines in New York by 1915 and to Idaho by 1927. A summary of the blister rust control program, the recent spread of the disease, and the present state regulations will be presented.