NASHVILLE (AP) — A fungal disease that kills sassafras trees is spreading in Tennessee, and the state Agriculture Department is seeking the public’s help to stop it.

Earlier this year, laurel wilt disease was detected in trees in Montgomery, Cheatham, Dickson and Williamson Counties. More recently, it has been detected in Robertson and Hamblen counties, according to a news release from the Tennessee Department of Agriculture.

“These new detections of this invasive disease show a significant geographic jump across the state,” State Forester David Arnold said in the statement. “This is yet another unfortunate example of an invasive pest impacting our forests.”

Laurel wilt is most likely in Tennessee due to human movement of contaminated wood, according to the department, and the best way to prevent its spread is to avoid moving firewood or untreated timber around the state.

Infected trees should be cut down and chipped with the chips either burned on site or covered with a tarp, according to the department.

Laurel wilt is transmitted by the wood-boring redbay ambrosia beetle and can affect a range of plants, including sassafras and spicebush. Signs of laurel wilt include browning leaves, leaf loss and staining of the inner bark. Those who suspect their trees might be diseased should contact the state Division of Forestry.