A perennial fusoid canker on eastern red cedar producing telia along the bark fissures.

Photograph courtesy Scott Enebak
Auburn University, School of Forestry
Auburn University, School of Forestry, 108 M. White Smith Hall, Auburn, Ala. 36849
E-mail: enebasa@auburn.edu

Background: Unseasonably warm, wet weather in Auburn, Alabama in January, 1999 resulted in the early production of telia of Gymnosporangium clavipes on this eastern red cedar. On close examination of this tree, and other cedar in the area,  23 similar cankers producing telia were found. The pathogen is found throughout North America, but the disease appears to be limited to the eastern US. Of the cedar rusts, G. clavipes has the widest host range and has been reported on over 480 species. While the fungus typically causes perennial cankers which appear as slight swellings on the stem or branches of eastern red cedar, the pathogen can kill smaller branches and weakened trees. The pathogen is more serious on the alternate hosts (apple, pear, quince, and many other rosaceous species) causing defoliation, fruit infection and branch and tree mortality. Management of this fungus on Rosaceous plants require the proper timing of fungicides and/or the elimination of eastern red cedar in the area.