Critical Issue

Piece’s disease (PD), a bacterial disease caused by Xylella fastidiosa is an economically significant plant disease that causes rapid decline and death in its hosts. State agencies representing the top wine grape producing nations have made statements, offered guidance,
and issued assistance in efforts to mitigate the damage caused by the pathogen. Between 1994 and 2000, over 1,000 acres of vineyards have been destroyed 1. Presently there is no treatment for Pierce’s disease other than destroying affected plants. The United States
Department of Agriculture (USDA) recognizes Homalodisca vitripennis (Glassy-Winged Sharpshooter, GWSS) as the most significant vector of Pierce’s disease.

The presence of GWSS was identified in California in the early 1990s, however PD is believed to have been the cause of the collapse of viticulture in Los Angeles in the 1880s 2. Due to the insect’s ability to fly further distances, live within a greater number of host plants than other PD vectors, and feeding habits, the GWSS is the primary target for managing the spread of PD. The feeding habits of the GWSS make it the most destructive vector; the ability
of GWSS to feed during winter is speculated to be the cause of chronic infections of PD that spread to adjacent vines more easily in the spring.

Research into methods of control are ongoing and controversial. The development of hybrid wine grape cultivars crossed between Vitis vinifera and V. arizonica have proven to have resistance to PD, however American consumers may resist purchasing wines composed of new varieties3.


  1. California Department of Food and Agriculture. CDFA – PDCP – Pierce’s Disease; [accessed
    2023 Jul 24].’s_Disease.html.
  2. Hopkins, D. L., & Purcell, A. H. (2002). Xylella fastidiosa: cause of Pierce’s disease of
    grapevine and other emergent diseases. Plant disease, 86(10), 1056-1066.
  3. There’s finally hope that California grapevines can be saved from Pierce’s disease. Global Plant Protection News. 2021 Aug 13 [accessed 2023 Aug 28].
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