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Root Diseases

Armillaria Mushrooms
Joseph O’Brien, USDA FS,
Armillaria Mushrooms

Root disease increases trees’ susceptibility to other pests, especially bark beetles, fire and windthrow. Stand composition, habitat type, soil conditions and climate all affect root disease incidence and severity. From a management perspective, it is important to consider the root diseases present in a forest stand before beginning fuels reduction thinning or harvesting operations.

Forest Service researchers study many of the fungi that cause root disease, such as Armillaria spp, Heterobasidion spp, and Phellinus spp.

The distribution of precisely identified, root-disease pathogens must be determined before invasive pathogens can be recognized and the influence of changing climate on root diseases can be predicted. DNA-based diagnostic tools have been developed to distinguish among species of Armillaria . An undescribed Armillaria species was found in Mexico that may represent an invasive pathogen risk to other areas with similar climate.

In the first study to assemble and characterize a transcriptome (set of functioning genes) of Armillaria spp., researchers profiled over 20,000 genes functioning in an active Armillaria root disease pathogen, an important step in understanding gene expression and how it relates to disease. To learn more, contact Ned Klopfenstein, a Research Plant Pathologist specializing in molecular diagnostics and evolutionary relationships between forest hosts and pathogens.

Find research publications about root disease on Treesearch.