Description
Laurel wilt is a fungal disease that kills trees and shrubs in the laurel family, including sassafras and spicebush. Despite its name, mountain-laurel is not in this family and is not impacted by the disease. Laurel wilt is caused by the invasive fungus Harringtonia lauricola and is spread by the invasive redbay ambrosia beetle, a tiny insect.
Once the fungus is introduced inside a tree, it spreads quickly, blocking water flow and causing death within weeks. Signs and symptoms to watch for include:
Leaves that suddenly wilt and turn brown;
Dark streaking of the sapwood beneath the bark; and
Small entry holes on the branches, trunk, or roots, which are sometimes surrounded by fine sawdust-like “toothpicks” pushed out from the bark that are created by the redbay ambrosia beetle.
Distribution
Laurel wilt was first found in Georgia in 2002 and has spread through much of the Southeast. Until recently, the farthest north it had been confirmed was in Virginia and Kentucky. In August 2025, the disease was confirmed for the first time in New York State on Long Island, marking the northernmost occurrence in the United States.
Habitat
In New York State, laurel wilt threatens two native plant species: sassafras, a small tree scattered across the state but especially common on Long Island and the lower Hudson Valley; and spicebush, a widespread native shrub found in moist forests, wetlands, and along streams. Both are key understory species that support wildlife and add diversity to New York’s forests.
Impacts
The arrival of laurel wilt in New York State poses significant risks to forests, wildlife, and ecosystems. Species at risk from laurel wilt, including sassafras and spicebush, typically die quickly after infection. Their loss would reduce forest diversity and change understory habitats across much of the state. Spicebush berries are a critical food source for migratory birds in the fall, while the leaves of both sassafras and spicebush support the caterpillars of many butterflies and moths, including the spicebush swallowtail and imperial moth. Declines in these insect species would negatively impact the food web as they are eaten by other insects and wildlife. Note that laurel wilt does not impact mountain-laurel, which is in the unrelated heath family.
Management
There is no known treatment for laurel wilt. Management focuses on slowing its spread to new areas.
How You Can Help
- Follow the NYS Firewood Regulation and do not move untreated firewood more than 50 miles.
- Leave dead trees in place. Don’t move trunks, branches, or bark from wilting sassafras or spicebush.
- Chip on site. If you remove affected trees, mulch them on your property.
- Report it. If you see sassafras or spicebush wilting or dying suddenly, report it through iMapInvasives or to DEC Forest Health.
