First report of verticillium wilt of Ailanthus altissima in Virginia caused by Verticillium nonalfalfae.
A. altissima, commonly known as tree-of-heaven, is an invasive tree species that has spread throughout the United States since its introduction in 1784. During a survey in July 2009, approximately 1 100 A. altissima trees were observed at two locations in western Virginia (a roadside in Montgomery Co. and a wooded area adjacent to a railroad in Bedford Co.) exhibiting foliar wilt symptoms, defoliation, yellowish vascular discoloration, or death at an incidence of ∼77%. Similar symptoms on A. altissima were reported in Roanoke (Virginia) in the early 1930s and after 2005 in Pennsylvania, attributed to a Verticillium sp. Based on morphological characteristics, molecular investigations (PCR assays) and pathogenicity test, the causal agent was identified as V. nonalfalfae. V. nonalfalfae is a recently proposed species that can infect a variety of plant species. This is thought to be the first report of this proposed species on A. altissima in Virginia. New state reports of this pathogen on A. altissima are important for regulatory issues associated with using this pathogen as a potential biological control agent.