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Pierce's Disease
Research Updates

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What is Pierce's Disease?

Pierce's Disease is a bacterial infection, which is spread by bugs that feed on grapevines, particularly the "glassy winged sharpshooter." Grapevines that become infected with PD can quickly become sick and die.

glassy-winged sharpshooter

DOCUMENTATION AND CHARACTERIZATION OF XYLELLA FASTIDIOSA STRAINS IN LANDSCAPE HOSTS

  • Author(s): Cooksey, Donald; Costa, Heather; Hernandez, Rufina; Wong, Frank;
  • Abstract: To document the incidence of Xylella. fastidiosa (Xf) in landscape ornamental hosts, in 2003 and 2004 a survey of plants showing symptoms of scorch or dieback in urban locations in southern California was done. A total of 1,670 samples, representing 161 plant species were taken and analyzed at five locations: Fillmore, San Diego, Redlands, Riverside, and Tustin. From the total, 35% of plants tested (591), representing 102 identified species, gave positive results by Xf-specific enzyme linked immunosorbent assay (ELISA). Isolation of bacteria from ELISA-positive plants provided 39 isolates form 14 non-previously reported as Xf-hosts species: almond, crapemyrtle, daylily, gingko, jacaranda, grapevine (both labrusca and vinifera), magnolia, mulberry, oleander, cherry, purple-leaved plum, heavenly bamboo, olive, sweetgum, plum and western redbud. Random amplified polymorphic (RAPD)- polymerase chain reaction (PCR) and sequence analysis of the 16S-23S rDNA intergenic spacer regions (ISR) was used to genetically characterize the strains. Strains isolated from daylily, jacaranda and magnolia grouped with members of Xf subsp. sandyi. Some strains isolated from cherry, and one strain isolated from western redbud, grouped with Xf subsp. fastidiosa members and strains isolated from purple-leaved plum, olive, peach, plum, sweet gum, maidenhair tree, crape myrtle and another western redbud strain, clustered with members of the Xf subsp multiplex. All strains isolated from mulberry and one from heavenly bamboo formed a cluster that has not yet been defined as a subspecies. Kochs postulates were successfully tested for the strains isolated from sweet gum, purple-leaved plum, western redbud and mulberry. Cross-infectivity of those strains to grapevine, almond and oleander was also tested. This information contributed to better understand the role of these different strains in causing disease on plants in urban landscapes. However, the impact of Xf infections in landscape hosts and the diversity of strains still are far from being fully understood.
  • Publication Date: Nov 2006
  • Journal: 2006 Pierce's Disease Research Symposium

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