Home Archived April 13, 2016

Blister Rust Wars in Western National Parks


When it was discovered in the 1920’s that white pine blister rust fungus had invaded North America from Eurasia, a massive national campaign was launched to save five-needled pines. In the plant equivalent of controlling predators to protect more
favored animals, blister rust’s alternate host, all species in the genus Ribes, were targeted for eradication within identified control areas. Between 1930 and 1971, 14.3 million plants of native ribes were removed from Glacier, Yellowstone, Grand Teton, Rocky Mountain, and Mount Rainier NP’s. While ribes eradication was accomplished by hand-pulling in most areas, chemical control was employed in some areas. This involved
"decapitating" the Ribes and spraying the root stock with a herbicide. During chemical Ribes removal, 536,000 gallons of 2-4-5T were sprayed in these national parks. The ineffectiveness of ribes removal in keeping trees rust free ended control efforts in 1971. However, larger issues, such as whether national parks should try to save one native species at the expense of another or at the risk of environmental contamination, remain difficult questions.



Content Information Contact: kckendall@usgs.gov