Date of Graduation
Davis College of Agriculture, Natural Resources and Design
Ailanthus altissima is a highly invasive exotic tree species entrenched throughout the United States. Since the discovery of a vascular wilt disease of Ailanthus in 2002, caused by the fungus Verticillium nonalfalfae, many studies are investigating its potential as a biocontrol focusing on efficacy, host specificity and disease transmission. This study addresses: the reproductive potential of Ailanthus; if V. dahliae alters Verticillium wilt progression; if hardiness zones influence the individual contributions of two Verticillium spp.; can a unique habitat affect biocontrol efficacy; and can the fungal proteome of V. nonalfalfae allow us to explain differences in host specificity? Cumulative seed production in individual Ailanthus reached ca. 10 and 52 million seeds over a 40-year and 100-year period, respectively. Forested sites inoculated with both Ailanthus pathogenic species of Verticillium experienced the same mortality rates as sites with just V. nonalfalfae alone. When comparing mortality caused by Verticillium wilt in three hardiness zones, it was found that there was no difference in disease progression. Ailanthus established on previous strip mine sites displayed resistance to the pathogen. Tree ring observations and X-ray fluorescence mineral assays indicated high concentrations of iron which inhibited Verticillium infection. Isolates of Verticillium species and strains from different plant hosts displayed differences in pathogenicity to Ailanthus seedlings and had distinct proteomes from each other when analyzed with MALDI-TOF-MS, indicating Verticillium isolates from different sources respond to their host environment differently.
Wickert, Kristen L., "Elucidating disease dynamics in the biocontrol of Ailanthus altissima while confirming the host specificity of the vascular wilt pathogen Verticillium nonalfalfae" (2019). Graduate Theses, Dissertations, and Problem Reports. 3854.