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Individual Highlight

Thousand-Cankers Disease Fungus Found in Indiana

Photo of Dorsal and lateral views of the bark-colonizing weevil found to carry the Thousand Cankers Disease fungus in Indiana. Janet C. Ciegler Dorsal and lateral views of the bark-colonizing weevil found to carry the Thousand Cankers Disease fungus in Indiana. Janet C. Ciegler Snapshot : Thousand-cankers disease (TCD) is caused by the canker-causing fungus Geosmithia morbida when carried by the walnut twig beetle. In an Indiana-wide trap tree survey of ambrosia beetles, bark beetles, and weevils colonizing stressed eastern black walnut, scientists detected the fungus on three bark-colonizing weevils from two trees on one site. This is the first report of the pathogen in Indiana and the first report of the fungus from an insect species other than the walnut twig beetle.

Principal Investigators(s) :
Juzwik, Jennifer 
Research Location : Indiana
Research Station : Northern Research Station (NRS)
Year : 2014
Highlight ID : 642


Thousand-cankers disease, characterized by decline and dieback in tree crowns, can lead to the death of the high-value eastern black walnut. The disease was first found in 2010 within the native range of eastern black walnut in Knoxville, Tenn.. The disease is caused by numerous infections of the fungus Geosmithia morbida transmitted by walnut twig beetles during their mass attack of susceptible trees. Forest Service scientists, with partners at the University of Missouri and Purdue University, used stem-girdled "trap trees" to detect the walnut twig beetle and to determine what other insect pests and fungal pathogens colonize stressed walnut in Indiana and Missouri. No walnut twig beetles were obtained from either state. However, the canker fungus was detected on three adults of the bark-colonizing weevil Stenomimus pallidus obtained from two forest plantation trees on a site in Brown County, Ind. This site yielded 21 of the total 435 weevils obtained from 12 sites within the state. G. morbida detection also was attempted, but not found, from weevils from the other sites specimens of four ambrosia beetle species and one bark beetle species obtained from the Brown County trees. A state-issued quarantine has been imposed on this site.

Forest Service Partners

External Partners

  • Bruce Moltzan, WO-FHP, provided Special Projects Funding for this research.
  • Jim English, University of Missouri-Columbia
  • Matt Ginzel, Dept. of Entomology, Purdue University
  • and Harlan Palm, Walnut Council. Missouri Department of Conservation and Indiana private landowners and public land managers provided study trees. The Walnut Council assisted with contacting landowners.