Spruce Rust (Chrysomyxa ledicola) Found on Kuskokwim River Bank

Observation by Rebecca Wilmarth via Meredith Witte:

Orange, rusty colored particulates were in the water, particularly along the banks. If you put your hand in the water, you would get tiny particulates on your hand. Not sure if this is pollen or something else.

Robin Mulvey, Southeast Alaska Forest Pathologist with the U.S. Forest Service, writes:

I feel very confident that that is spruce needle rust, given the appearance, location and timing (sporulation on spruce generally occurs starting the 3rd week of July through late August)! 9/13/2018

Comments from LEO Editors:

Spruce rust (Chrysomyxa ledicola) is caused by a fungus that attacks new black spruce needles and Labrador tea. Infected spruce needles remain green for about a year, before turning a reddish-brown. The fungus doesn't have a long term impact on the health of the tree, and doesn't pose any threat to human or animal health. Source: U.S. Forest Service - Forest and Grassland Health, Spruce Needle Rusts, USDA - Spruce Needle Rust

In 2012, these fungal spores covered the lagoon and mouth of the Wulik River near Kivalina. Although there are no black spruce trees near Kivalina, experts speculated that the spores drifted downstream, or were blown in to the area by wind. Erica Lujan