Causal organism is xylem inhabiting bacteria: Xylella fastidiosa (Xf). Sharpshooter: (BGSS) Graphocephala atropunctata (GWSS) Homalodisca vitripennis  (Cicadellidae: Homoptera) PD symptoms Disease cycle/Mode of transmission

1. PIERCE’S DISEASE OF
GRAPEVINES
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Muhammad Kamran M.Sc(Hons) Agri.Entomology
University College of Agriculture,
University of Sargodha
Pakistan

2. Pierce’s disease of grapevines
o First described in California in 1892.
o Pierce’s disease (PD) of grapevines is a lethal disease.
severely limits areas where grapevines can be grown.
o Causal organism is Xylella fastidiosa (Xf).
o Xf is a gram-negative bacterium, specific strains are capable
of infecting grapevines.
o The Xf bacterium resides in the xylem of the grapevine.
o PD is transmitted to the grapevine by:
• Sharpshooter: (BGSS) Graphocephala atropunctata
(GWSS) Homalodisca vitripennis
(Cicadellidae: Homoptera)
• Spittlebugs
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3. ENT-710
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(courtesy A.C. Goheen; reproduced from Compendium
of Grape Diseases, 1988, American Phytopathological
Society, St. Paul, MN).
The glassy-winged
sharpshooter leafhopper
o Typical PD symptoms begin to appear in hot and dry weather.
o Reliable diagnosis is dependent upon
• Bacterial culturing
• Enzyme-linked immunosorbent assay (ELISA)
• Polymerase chain reaction (PCR).
Photos by Damon Smith, Oklahoma State University
Symptoms consisting of marginal leaf
necrosis, leaf blade drop, leaf scorch,
shriveled berries, dieback, and death
(courtesy B. Bextine, Fletcher and Wayadande, 2002, The Plant
Health Instructor).

4. Disease cycle/Mode of transmission
• Acquisition efficiency is directly proportional to the
population of the bacteria from the infected hosts and the
sharpshooter feeding site.
• Attachment or retention of the acquired bacteria into the
vector foregut forming a biofilm.
• Pathogen must be detached and introduced into a new
host during vector feeding.
• Bacterial cells attach to the xylem vessel and multiply
forming biofilm-like colonies that occlude the xylem.
• Disrupts water transport throughout different parts of the
plant exacerbated by gum deposits, tyloses or deposition of
other bacterial- or plant-derived compounds.
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5. Management
• Winter temperatures at or below 10ºF for two to three
days is required for a vineyard to be considered at low-
risk for Pierce’s disease. Otherwise, vineyards are
considered at medium- to high-risk (Anas et al., 2008).
• Purchasing clean stock from a reliable source.
• Use systemic insecticides to control insect pests in
vineyards.
• No chemical management options currently exist for
Pierce’s disease.
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