Characterizing Xylella fastidiosa, its genetic diversity and virulence in southern highbush blueberries

Known for its wide host range, Xylella fastidiosa (Xf) is an emerging plant pathogenic bacterium of global importance. This pathogen causes bacterial leaf scorch (BLS) on southern highbush blueberry (Vaccinium corymbosum interspecific hybrids), a relatively new disease affecting this important fruit crop in the southeastern United States. In Georgia, USA, few Xf isolates from blueberry have been studied. This thesis investigated 1) the presence of the bacterium through multiple field surveys of blueberry plantings and the genetic diversity of obtained isolates; 2) the capability of such isolates to induce BLS in blueberry after artificial greenhouse inoculations; and 3) the association of observable BLS symptoms with actual pathogen presence in field conditions. Novel Xf genetic types capable of causing significant BLS symptoms were isolated from naturally infected blueberries. However, reliable prediction and management strategies for this disease still need to be devised.