Laurel wilt study looks at disease impact to sassafras trees

The scent of a crushed sassafras leaf is unforgettable—sweet, pungent, fragrant. The fragrant oil distilled from the rootbark is used in some perfumes, and for scents in soap. In some parts of the South the leaves are used as a condiment in sauces and soups, to flavor beers and brew tea. Insects and wildlife use it as a food source. But the Sassafras tree is under threat from laurel wilt disease.

The disease is caused by a fungus that is introduced into host trees by a nonnative insect, the redbay ambrosia beetle. Once the fungus is unleashed it can kill the tree within a few weeks. Laurel wilt disease affects all members of the laurel family—sassafras, redbay, swamp bay, pondberry and avocado.

“Sassafras is susceptible to laurel wilt disease,” says KaDonna Randolph, Forest Service Southern Research Station research mathematical statistician. “The disease has not reached the heart of the sassafras range, but it is spreading throughout the Southeast.”

Randolph’s study, “Status of Sassafras albidum (Nutt.) Nees in the presence of laurel wilt disease and throughout the eastern United States,” was recently published in the Southeastern Naturalist. The study was based on Forest Inventory and Analysis unit data from 2014, which shows almost two billion sassafras trees and saplings grew in the U.S. across 28 states.

“Landowners and forest managers within the range of sassafras should be diligent,” says Randolph. “Watch for laurel wilt disease and consider the changes that may occur in forests if it becomes established.”

Close-up of sassafras leaves.
Healthy sassafras leaves. Photo courtesy Vern Wilkins, Indiana University, Bugwood.org.
Close-up of staining caused by laurel wilt.
Vascular staining caused by a fungus introduced by Xyleborus glabratus. Note beetle attack site to left of fingernail. Photo courtesy Albert (Bud) Mayfield, USDA Forest Service, Bugwood.org.