EFFECTS OF GROUP, CULTIVAR, AND CLIMATE ON THE ESTABLISHMENT AND PERSISTENCE OF XYLELLA FASTIDIOSA INFECTIONS CAUSING ALMOND LEAF SCORCH

• Author(s): Daane, Kent; Purcell, Alexander; Kirkpatrick, Bruce; Wistrom, Christina;
• Abstract: Almonds are one of the most widely-grown crops that can host Xylella fastidiosa (Xf), so it is useful to assess the potential for almonds to serve as a source of Xf infections in grapes, and to explain why Xf dispersal between almond orchards and vineyards is uncommon. We are comparing infection establishment and survival at two field sites and in a controlled test with potted plants, varying three factors that may influence almond leaf scorch in almonds: cultivar, genetics of the pathogenic bacteria, and winter severity. In spring and summer 2005, we inoculated grape type and two almond types of Xf into highly susceptible Peerless and less-susceptible Butte almond trees. After vector inoculation, Xf must survive multiple winters in an almond tree to reach sufficient populations for sharpshooter acquisition and economic impact disease levels. Therefore, field sites were selected with moderate and severe winter temperatures. We also initiated a controlled dormancy test with potted plants and cold storage rooms at Kearny Agricultural Center, Parlier, California. Almond trees in the field were inoculated with buffer or Xf belonging to the grape type or two almond types, and will be held at different chill temperatures for varying lengths of time.
• Publication Date: Dec 2005
• Journal: 2005 Pierce's Disease Research Symposium