Skip to Main navigation Skip to Left navigation Skip to Main content Skip to Footer

University of Minnesota Extension
www.extension.umn.edu
612-624-1222

Extension > Garden > Diagnose a problem > What's wrong with my plant? > Evergreen Trees and Shrubs > Pine > Woody growth or swelling

Print Icon Email Icon Share Icon

Pine > Trunk/Branches > Woody growth or swelling

1 of 2
  • Image: 1
  • Image: 2
  • Image: 3

Pine-Pine gall rust and Pine-Oak gall rust
Endocronartium harknessii and Cronartium quercuum f.sp. banksii

  • Round to oblong woody galls on branches and stems
  • Bark on galls cracks and releases bright orange to yellow powdery spores in spring
  • Young infected trees can be killed by main stem galls
  • Flagging, branch dieback, poor growth and witches' broom occurs on mature infected trees
  • Most common on Jack pine, but infects many 2 or 3 needled pines
  • Need a lab analysis to distinguish the two diseases
  • More information on Pine-Pine gall rust...
2 of 2
  • Comandra 1
  • Sweetfern rust 2
  • Stalactiform 3

Comandra, Stalactiform or Sweetfern rust
Cronartium comandrae, Cronartium coleosporioides, and Cronartium comptoniae

  • When severe, canopy is thin, has poor growth, needles yellow, turn brown and die
  • On young stems or branches, infection may appear as a swollen, elliptical area
  • Infection develops into a long, flattened, resin soaked canker on the main trunk
  • Sweetfern rust cankers frequently occur near the soil level and grow up to 6 ft. long
  • Stalactiform rust cankers grow up to 25 ft. long along the main trunk
  • Comandra rust cankers occur on the main trunk and rarely grow over 4 ft. long
  • Ridges of wound wood may be present along edges of the canker
  • Pale yellow blisters of powdery spores break through cracks in bark in spring, sticky orange drops form along canker edges in late summer to fall
  • Jack and ponderosa pine most severely affected, but many 2-3 needle pines are susceptible
  • Differentiation between the 3 species is most accurate with a lab analysis

Don't see what you're looking for?

  • © Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer. Privacy