page_title: Verticillium nonalfalfae
section_title: Host and Symptoms
hierarchical_section_title: Verticillium nonalfalfae / Host and Symptoms
caption_attribution_description: Joanne Rebbeck, a Research Scientist and Timothy Fox, a Biological Research Technician, both from the USDA Forest Service Northern Research Station inoculated Ailanthus trees with Verticillium nonalfalfae (V. nonalfalfae) to evaluate how effective it might be in controlling Ailanthus. (Photo courtesy of USDA Forest Service, Wayne National Forest)
context_page_description: Verticillium nonalfalfae is a soilborne fungus in the order Hyppocreales. It causes verticillium wilt in some plant species, particularly Ailanthus altissima. It produces yellow-pigmented hyphae, while producing resting mycelium. It is most closely related to V. albo-atrum and V. alfalfae.
context_section_description: Verticillium nonalfalfae has a wide host range including hops, kiwifruit, spinach, solanaceous plants like eggplants and potatoes, and tree of heaven (A. altissima). Systemic infections appear on most hosts showing vascular wilts caused by xylem blockage. Additional symptoms including vascular discoloration and defoliation show almost exclusively on A. altissima. V. nonalfalae tends not to infect non-target plants. Unlike V. alfafae, it does not infect alfalfa.
  The symptoms of V. nonalfalfae include vascular wilting due to the blockage of vascular system and defoliation and these symptoms may occur at the same time. V. nonalfalfae is a soilborne fungus whose infecting structures can be pulled up by plants’ vascular system and plug up xylem tissues of hosts.
  One important host of V. nonalfalfae is hops. The symptoms of hosts infected by V. nonalfalfae on hops are categorized into two pathotypes: mild and lethal. Mild pathotypes primarily cause symptoms of curling and leaf tissue death.  Hops infected by V. nonalfalfae with the mild pathotype generally can survive the infection. For the lethal pathotype of V. nonalfalfae on hops, hosts suffer from rapid weakening that ultimately leads to death. The lethal form was discovered in hops in the 1940s in the United Kingdom and elsewhere in Europe later. Two pathotypes share similar peroxidase, which are thought to be contribute to their pathogenicity.
  Another important host of V. nonalfalfae is Ailanthus altissima, also known as tree of heaven. This species of Ailanthus was introduced in the northeastern United States from the 1790s.  Spreading widely and quickly, it is considered to be an Invasive species.  V. nonalfalfae is being studied as a biological control of A. altissima. Symptoms of verticillium wilt on tree of heaven appear quickly after inoculation, according to studies.
caption: Joanne Rebbeck, a Research Scientist and Timothy Fox, a Biological Research Technician, both from the USDA Forest Service Northern Research Station inoculated Ailanthus trees with Verticillium nonalfalfae (V. nonalfalfae) to evaluate how effective it might be in controlling Ailanthus. (Photo courtesy of USDA Forest Service, Wayne National Forest)
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