Cytospora or Leucostoma canker, the most common and damaging disease of spruce, is caused by the fungus Leucocytospora kunzei, synonym Cytospora kunzei (teleomorph or sexual state Leucostoma kunzei, synonym Valsa kunzei). This canker occurs on several conifers from New England to the western United States. Colorado or Colorado blue (Picea pungens) and Norway spruce (Picea abies), used for ornament and in wind-breaks, are the species most commonly affected in Illinois. The disease has reached epidemic proportions on Engelmann spruce (Picea engelmannii) and Douglas-fir (Pseudotsuga menziesii) in the eastern Rocky Mountains due to a succession of dry years in the area. Other trees reported as susceptible to the disease are given in Table 1.

Click here to read more about Cytospora of Spruce