What is verticillium wilt?

Verticillium wilt results from infection by soil fungi (Verticillium dahliae or V. albo-atrum) that enter trees through the root system and colonize the water-conducting tissues. Once established, the fungus blocks water movement within the tree, causing characteristic wilting, yellowing, and branch dieback that often progresses over multiple seasons.

The disease is particularly problematic in Westchester because the fungus persists in soil indefinitely, surviving on plant debris and making affected areas a long-term hazard. Maples, especially sugar and red maples, are highly susceptible. Other common landscape trees including ash, magnolia, and fruit trees are also vulnerable. Symptoms typically appear first on one side of the canopy as leaves wilt during warm weather, even when soil moisture is adequate. Affected branches show discoloration in the sapwood when cut.

Unlike some tree diseases, verticillium wilt has no cure once established in a tree. Management focuses on prevention through proper site management, avoiding transplanting trees to infested soil, and removing infected trees to prevent spread. Professional arborists can assess trees for the disease and recommend whether removal or containment measures are appropriate for your property.