page_title: Verticillium nonalfalfae
section_title: Disease Cycle
hierarchical_section_title: Verticillium nonalfalfae / Disease Cycle
caption_attribution_description: English: Common hop plants showing foliar symptoms of Verticillium wilt caused by Verticillium albo-atrum on a field at Oregon, USA.
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 is a fast-killing soilborn fungus native to America. Its disease cycle is similar to Verticillium spp. cycle with minor differences. V. nonalfalfae overwinters by producing resting structure of mycelium in soil, unlike V. dahliae producing microsclerotia.
  Conidia is the major infecting agent for Verticillium nonalfalfae. V. nonalfalfae produces conidia in the soil in the spring from conidiophores. It has been found that intraspecific grafting enhances V. nonalfalfae’s dispersal of conidia, meaning that conidia from disease root can be transported to healthy root tissues of host intraspecifically. One way of conidia transmission in V. nonalfalfae is through mechanical dispersal where the conidia attaches to cutting tools and spread to another plant grafting and transporting. For dispersal of hops, V. nonalfalfae is spread in hop yards during soil cultivation, in hop trash, in planting materials from infested yards, and in soil moved on equipment and workers. Long-range transportation of conidia involves insects including ambrosia beetles, which are thought to be critical in creating regional epidemics of wilting on Ailanthus.
  It is not possible to differentiate V. nonalfalfae and V. alfalfae from V. albo-atrum consistently, just using morphological features. Verticillium albo-atrum may be found in co-infections with V. nonalfalfae on some hosts. The hyphae penetrate the root epidermal cells of hosts and enter xylem and the fungus spreads by producing large amount of spores.
caption: Common hop plants showing foliar symptoms of Verticillium wilt caused by Verticillium albo-atrum on a field at Oregon, USA.
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