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Comandra blister rust

Comandra blister rust - A jack pine stem with matures spores of <em>Cronartium comandrae</em>, the causal agent of comandra blister rust.
  • Latin name: Cronartium comandrae Peck
  • French name: Rouille - tumeur oblongue
  • Division: Basidiomycota
  • Class: Uredinales
  • Synonym(s): Cronartium asclepiadeum (Willd.) Fr. var. thesii Berk.,
    Cronartium pyriforme Hedgc. & W.H. Long





Damage, symptoms and biology

Trees of all sizes and ages are affected, and the presence of cankers can result in growth defects and mortality. Outbreaks of this disease are sporadic, due to variations in the distribution of the alternate host and the periodicity of environmental conditions necessary for infection. The most serious damage has been observed in nurseries and plantations where rapid stem girdling results in high mortality.

A large numbers of galls reduces the aesthetic appearance and value of ornamentals and Christmas trees.

Other information

The aecial cankers of comandra blister rust are very similar in appearance to those of sweet-fern and stalactiform rusts. However, examination of the uniquely shaped aeciospores with a microscope or even a hand-lens will distinguish this rust from others. Swellings on seedlings might be confused with pre-sporulating gall of Endocronartium harknessii; however, C. comandrae swellings result from swollen bark, while E. harknessii galls have normal bark over abnormally thickened xylem tissue.

Canadian Forest Service Publications

Comandra blister rust

Information on host(s)

Main host(s)

, jack pine, Northern comandre, ponderosa pine, shore pine

Secondary host(s)

Mugho pine, pitch pine, scots pine


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