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Individual Highlight

Wood Heat Treatment Reduces the Risk of Spreading of Thousand Cankers Disease

Photo of Forest Service entomologists Bud Mayfield left) and Paul Merten (right) examine the bark of a black walnut branch for evidence of the walnut twig beetle, the vector of the fungus that causes thousand cankers disease. USDA Forest ServiceForest Service entomologists Bud Mayfield left) and Paul Merten (right) examine the bark of a black walnut branch for evidence of the walnut twig beetle, the vector of the fungus that causes thousand cankers disease. USDA Forest ServiceSnapshot : Black walnut, one of the most valuable hardwood timber species in the United States, is being killed by "thousand cankers disease" which is caused by a tiny bark beetle and an associated fungus. The disease organisms can spread to new areas through the movement of infested walnut logs, firewood, or other unprocessed wood products that are commonly transported for commercial trade. Forest Service scientists and their research partners developed a heat treatment schedule that eliminates both the bark beetle and fungus from infested walnut logs to help slow the spread of thousand cankers disease in the U.S. and abroad.

Research Location : University of TN, Knoxville T
Research Station : Southern Research Station (SRS)
Year : 2014
Highlight ID : 724

Summary

Black walnut, one of the most valuable hardwood timber species in the United States, is being killed by "thousand cankers disease" which is caused by a tiny bark beetle (the walnut twig beetle) and an associated fungus. The disease organisms can spread to new areas through the movement of infested walnut logs, firewood, or other unprocessed wood products that are transported for commercial trade. Heat is a common treatment applied to wood products to kill pests in the wood or bark and make them safe for transport. By steam-heating infested walnut logs to various temperatures in a kiln, and then sampling/monitoring those logs after treatment, Forest Service scientsits and their research partners determined that a temperature of at least 56°C in the outer sapwood for 40 minutes is sufficient to kill all live walnut twig beetles and their associated fungus. This heat treatment schedule represents an effective management tool that can be used to reduce the risk of spreading thousand cankers disease through the walnut wood products industry.

Forest Service Partners

External Partners

  • Paul Merten, Entomologist, Forest Health Protection, Region 8
  • Stephen W. Fraedrich, Research Plant Pathologist, Southern Research Station
  • Adam Taylor, University of Tennessee
  • Scott W. Myers, Center for Plant Health Science and Technology, USDA-APHIS

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