|Lodgepole pine with multiple galls.|
|Old stem gall. Note rough surface of bark.|
|Symptoms resulting from complete girdling.|
|Infections on stems of young trees often result in hip cankers as the trees grow.|
Do any of these images look familiar to you? You may have pine trees invested with Western Gall Rust. Kathy Wyse contacted the Ministry of Forests to ask about this problem, and was advised that this is a common health issue in young pine. Galls on the main stem will girdle the tree and kill it.
What can you do about it?
- Cut off and burn all galls that are on branches. This will reduce the spread on your own trees, but keep in mind that spores travel several kilometres.
- Cut off the main stem below the gall and burn the tops. The tree will then grow like a bush, but it will live.
If we all check the trees in our yards and do what is recommended, it could save some of our young trees.
From the Ministry of Forests and Range website:
Distribution: Throughout B.C. Host
Susceptibility: Highly susceptible species are lodgepole and ponderosa pine.
Signs & Symptoms: Western gall rust produces round woody swellings on stems and branches. Orange spores are produced on galls in late spring. These spores directly infect other pines through elongating leaders and branch shoots. Suitable climatic conditions that occur every few years result in "wave years" of infection. The fungus is an obligate parasite and remains alive as long as the host branch or stem. However, infections stop releasing spores after about age 10. Most stem infections occur below a height of 3 m. Hip cankers result in distorted growth from partial stem girdling. Infected bark can be fed upon by squirrels.
Damage: Western gall rust is very common throughout the range of lodgepole pine. Stem galls often lead to mortality either through girdling or through stem breakage. Branch galls do not cause serious harm. The disease is usually more evenly distributed throughout stands than blister rusts, which require an alternate host.
Can Be Confused With: Small galls can be confused with Comandra infections, particularly when spores are present. Gall rust produces distinct woody swellings while blister rusts do not.Thank you, Kathy Wyse, for looking into this!
Photos from Forest Practices Branch, Ministry of Forests and Range.