photo: fergusonMary Helen Ferguson

Graduate Student
Major Professor: Dr. Christopher Clark


  • Ph.D. student, Plant Health (Plant Pathology), Louisiana State University (2012 - present)
  • M.S., Horticultural Science, North Carolina State University (2006)
  • B.S., Biology (Math minor, Distinction in Leadership Studies, Magna Cum Laude, Phi Beta Kappa), Birmingham-Southern College (2004)

Current Research:

Xylella fastidiosa is best known as the bacterial pathogen that causes Pierce’s disease of grape.  It also causes disease on peach (peach phony disease), almond (almond leaf scorch), citrus (citrus variegated chlorosis), oak (oak leaf scorch), and other plants.  Since 2004, researchers in Georgia and Florida have confirmedX. fastidiosa as the cause of a leaf scorch disease of southern highbush blueberries (Vaccinium corymbosum interspecific hybrids) (Chang et al., 2009; Harmon and Hopkins, 2009).  Inoculation of rabbiteye blueberry plants (Vaccinium ashei Reade) with Xylella fastidiosa resulted either in no detected infection or in local colonization of a limited number of plants (Chang et al., 2009).  However, X. fastidiosa has been detected in samples from rabbiteye blueberry orchards in Louisiana that have experienced plant stunting and/or death. 

I am investigating whether or not Xylella fastidiosa infection is correlated with reduced yield and plant death in rabbiteye blueberry.  I also plan to investigate differences in the susceptibilities of common rabbiteye blueberry cultivars to X. fastidiosa and the degree of similarity between the X. fastidiosa strain in rabbiteye blueberry and that which has been found to cause bacterial leaf scorch in southern highbush blueberry plants. 

Questions that I intend to answer include the following:

  • Does concern about the presence of X. fastidiosa in rabbiteye blueberry appear to be justified by correlations with reduced yield and/or plant survival?
  • Are some rabbiteye blueberry cultivars more resistant or tolerant to X. fastidiosa than others? 
  • Do rabbiteye blueberry plants provide a source of X. fastidiosa inoculum for susceptible Southern highbush blueberry cultivars?

Work Experience:

  • Graduate Assistant, Louisiana State University (2012-present)
  • Associate Extension Agent, Agriculture – Horticulture, North Carolina State University (2012)
  • Assistant Extension Agent, Agriculture – Horticulture, North Carolina State University (2007-2012)
  • Research and Teaching Assistant, North Carolina State University (2004-2006)