Watching over the sassafras trees: Federal and state forestry agencies monitor deadly tree disease together
Laurel wilt is a tree disease that rapidly kills sassafras and other trees in the Laurel family. The impact of laurel wilt on sassafras trees in the Appalachian Mountains and the Piedmont is likely to be severe, as a collaborative three-year monitoring project recently showed. The partners include the USDA Forest Service and eight state forestry agencies.
Laurel wilt is a deadly vascular disease of trees in the Laurel family. It is caused by a nonnative insect-pathogen complex. The USDA Forest Service and eight state forestry agency partners recently completed a three-year project to assess the occurrence and impact of laurel wilt spreading into sassafras trees in the Piedmont and in the Appalachian Mountains of the eastern U.S.
Sassafras grows in more than 28 states and reaches its largest form in the Appalachian Mountains. Sassafras is valued for its ecological functions and durable wood. There are also long cultural and culinary traditions around the tree’s fragrant leaves and roots.
As the monitoring effort showed, sassafras mortality due to laurel wilt increased rapidly from 2018 to 2020. Death occurred in small and large trees alike. Trapping for the redbay ambrosia beetle, which spreads the disease, did not improve early detection of latent laurel wilt infections. Seasonal flight activity of the redbay ambrosia beetle in the Piedmont and Mountains suggests two generations per year with little to no flight from December through March.
The results suggest that laurel wilt will continue to spread, killing sassafras trees wherever it goes. However, a georeferenced network of plots was established during the project. This network can provide baseline data for future monitoring efforts and can be revisited to look for evidence of sassafras resistance to laurel wilt.
- Principal Investigators
- Albert E. Mayfield III, Research Entomologist
- Rabiu Olatinwo, Research Plant Pathologist
- Bryan Mudder, Biological Science Technician
- Stephen W. Fraedrich, Plant Pathologist (Retired)
- 4552 - Insects, Diseases, and Invasive Plants
- Spread, vector flight behavior, and impact of Laurel Wilt in Sassafras beyond the Gulf-Atlantic coastal plain
- Research Partners
- Jaesoon Hwang, State and Private Forestry, Forest Health Protection
- Wood Johnson, State and Private Forestry, Forest Health Protection
- Jessica McKenney, State and Private Forestry, Forest Health Protection
- Paul Merten, State and Private Forestry, Forest Health Protection
- Robert Rabaglia, State and Private Forestry, Forest Health Protection
- Marc Digirolomo, State and Private Forestry, Forest Health Protection
- Karen Reed, Southern Research Station
- Matt Cloud, Southern Research Station
- Susan Best, Southern Research Station
- Ashleigh Hillen, Southern Research Station
- Deanna Tipton, Southern Research Station
- External Partners
- Alabama Forestry Commission: Dana Stone, Mary Claire Smith, Kacey Gordon
- Arkansas Forestry Commission: Chandler Barton, Brady Bradley, Brayden Fisher
- Georgia Forestry Commission: Chris Barnes, Mark McClure, Lynne Womack, Greg Klett, Chip Bates
- Kentucky Division of Forestry: Alexandra Blevins, James Morris, Abe Nielsen
- North Carolina Forest Service: Jim Slye, Wayne Langston, Brian Heath, Craig Lawing, Kelly Oten, Rob Trickel
- North Carolina State University: Cavell Brownie
- South Carolina Forestry Commission: David Jenkins
- Tennessee Department of Agriculture, Forestry: Nathan Hoover, John Henderson, Sam Gildiner
- Virginia Department of Forestry: Lori Chamberlin, Katlin DeWitt, M. Mulroy-Goldman
- Virginia Department of Conservation and Recreation: Erik Molleen, Nathan Curtis, M. Fulford