Epidemiology and Effects of a Leaf Spot Disease in Veratrum viride (Melanthiaceae)

Fungal phytopathogens can cause disease epidemics in crops, weeds, and populations of native plants. To investigate the effects of a foliar phytopathogen on Veratrum viride, a native herbaceous species in Tennessee, a demographic and disease assessment was carried out on two high-elevation, grassy bald populations on Roan Mountain, Carter County, Tennessee. A leaf spot disease affected all plants in both populations, causing widespread premature senescence of leaves and stems. Disease severity increased over the course of the growing season. Based on host identity, disease symptoms, and fungal conidia morphology, a cercosporoid fungus in the Mycospaerellaceae, most likely Mycocentrospora veratri or Pseudocercosporella sublineolata, was the probable causal pathogen. A study of herbarium specimens showed no evidence that the disease was epidemic in the species and no evidence of an increase in disease prevalence over time. However, the disease was more common in the mid-Atlantic and southern Appalachian regions and rarer in New England.