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Possible Biocontrol Agent for the Invasive Ailanthus Tree Is Tested

Photo of Inoculation of ailanthus tree with fungal spores by a researcher in Wayne National Forest. USDA Forest ServiceInoculation of ailanthus tree with fungal spores by a researcher in Wayne National Forest. USDA Forest ServiceSnapshot : Forest Service scientists from the agency’s Northern Research Station are studying a native fungus and find that it kills ailanthus (tree-of-heaven) while sparing native tree species. Inoculations in research trials that began in Ohio appear to be successful.

Principal Investigators(s) :
Rebbeck, Joanne 
Research Location : Five forested sites in Ohio - 1. Marietta Unit, Wayne National Forest; 2. The Wilds, Cumberland Ohio; 3. Tar Hollow State Forest; 4. Perry State Forest; 5. Blue Rock State Forest
Research Station : Northern Research Station (NRS)
Year : 2015
Highlight ID : 851


Ailanthus (tree-of-heaven), a nonnative invasive tree from Asia, is a prolific seeder and sprouter that is difficult to control with herbicides or cutting and is increasing in northeastern forests, but, there may be an alternative biocontrol in the near future. In 2002, researchers at Pennsylvania State University isolated the fungus Verticillium nonalfalfae from dead and dying ailanthus trees within forested areas of Pennsylvania. After rigorous testing and numerous trials, this soil-borne fungus was found to be very specific and deadly to ailanthus. In 2012, the fungus was isolated in Ohio by Forest Service scientists at the agency’s Northern Research Station who began greenhouse tests in 2013 to verify that native tree species in Ohio are not susceptible. After two growing seasons, no signs of wilt have been observed in seedlings from native Ohio sources of ash, beech, elm, and oak (black, chestnut, northern red oak, and white). In May 2015, fungal inoculations began in research plots in Ohio forests with trials testing the effectiveness of the fungus in killing ailanthus and also monitoring subsequent regeneration following eradication of ailanthus. Within 2 weeks of stem-inoculations with fungal spores, ailanthus trees began yellowing, wilting, and losing leaves; disease symptoms progressed and trees began to die over the summer.

Forest Service Partners

External Partners

  • Donald Davis and Eric O’Neal, Pennsylvania State University
  • Matthew Kasson, West Virginia University
  • Rachael Glover, The Wilds, Cotton Randall, Ohio Department of Natural Resources Division of Forestry, and Sierra Patterson, Wayne National Forest

Program Areas