"White pine blister rust, caused by the rust fungus Cronartium ribicola, is a textbook example of a heteroecious rust fungus. Its life cycle, symptoms, and climatic requirements are typical of most native western rust fungi.

"Hosts -- C. ribicola can infect nearly all white pines and is restricted to this group. Its native North American hosts are eastern white pine (Pinus strobus), western white pine (P. monticola), sugar pine (P. lambertiana), limber pine (P. flexilis), whitebark pine (P. albicaulis), bristlecone pine (P. aristata and P. longaeva), foxtail pine (P. balfouriana), and Mexican white pine (P. strobiformis). In addition, it infects all species of the genus Ribes, its alternate host.

"Distribution and damage -- The disease was introduced into North America in the early 1900's on seedlings of eastern white pine grown in Europe. It was not native to Europe, however, but is believed to have been introduced into that continent from Asia. Its introduction to North America resulted in one of our most serious outbreaks on conifers. White pine blister rust is now widely found in northeastern United States, the Lake States, and the West. In was introduced into British Columbia in 1910 and has spread from there throughout most white pine regions of Washington, Idaho, Montana, Wyoming, Oregon, and California.

"In North America, white pine blister rust has caused more damage and costs more to control than any other conifer disease. Since the 1920's, millions of dollars have been spent on the eradication of the alternate host, Ribes, and thousands of white pine stands have been severely damaged. In the western United States and Canada, some stands have been completely destroyed. When the main stem of a tree is invaded, death is only a question of time."

Citation

This page is from the Gymnosperm Database
URL: http://www.geocities.com/~earlecj/pi/pin/blstrust.htm
Edited by Christopher J. Earle
E-mail:earlecj@earthlink.net
Last modified on 29-Jun-1997