Cronartium ribicola

Cronartium ribicola, commonly known as white pine blister rust, is a fungal pathogen common in Oregon and Washington.

Description:  This pathogen first causes yellow and red spots on pine needles, and then later swellings on the branches.

Identification: 

Hosts: 5-needled pines, specifically Western white pine, sugar pine, whitebark pine, and limber pine.

Distribution:  Common throughout the range of the hosts.

General Information:

Sources: Field Guide to the Common Diseases and Insect Pests of Oregon and Washington Conifers