Date of Award
Master of Science (MS)
Plant and Environmental Science
Dr. Julia Kerrigan
Dr. Guido Schnabel
Dr. Jane Stewart
In 2016, a survey was conducted into the causes of twig blight on peach (Prunus persica) in five orchards across South Carolina. From this survey, isolates from the fungal genus of Cytospora (Sordariomycetes, Diaporthales) were reported on peach, for the first time, within the state. Cytospora species are known to cause oozing cankers on a wide range of woody hosts leading to dieback, loss of limbs, and reduction in yield, prompting concern for important economic crops. Past methods of identification of Cytospora species have been confounded by indistinguishable morphology, overlapping host preference among species, and genetic sequencing of barcoding regions lacking species-level delineation capabilities. Therefore, for identification to species, the combined use of morphology and genetic sequencing using multiple gene loci are required. In this study a combination of morphological descriptions of asexual structures and sequencing data from four loci, actin (ACT), beta tubulin (TUB), calmodulin (CAL), and translocation elongation factor (EF1α), were used to reach a species-level description of Cytospora isolates from South Carolina. Sequencing data combined from three gene regions, ACT, TUB, and EF1α, show that all but two isolates shared a 99% similarity to Cytospora plurivora, a recently described species on peach in California. Morphological measurements of conidia and conidiophores on detached twigs from selected isolates are consistent with that of C. plurivora. The remaining two isolates were found to have a 95% similarity to C. erumpens, but further study is needed to strengthen this species identification.
Baker, Stephen T., "Identification of Cytospora Species Isolated from Canker in Peach Trees in South Carolina" (2022). All Theses. 3738.