Wednesday, September 6, 2017

Pierce's Diease...What is it and Why It's important to fight it



Pierce's Disease is a deadly disease of grapevines. It is caused by the bacterium Xylella fastidiosa, which is spread by xylem feeding leafhoppers known as sharpshooters. There's no way to stop it right now. Scientists are conducting volumes of research to fight this insect and reduce disease infection on vines. Moreover, scientists are studying methods to prevent the spread of Pierce's Disease on wine grapes entirely.

Pierce's Disease is known to be prevalent within the USA from Florida to California, and outside the USA in Central and South America. Xylella fastidiosa works by blocking the xylem, which conducts the water around the plant. 

Symptoms include chlorosis and scorching of leaves, and entire vines will die after 1-5 years. Pierce's Disease is less prevalent where winter temperatures are cold, such as more northern areas, high altitudes and inland areas.

Basically in grapevines, unlike some other fruits it gets detected too late; it is too late fight it when that signal comes; the plant is already dead. So heavy research is being done in modifying the rootstock of vines to automatically generate that same protein for when the bacteria enters the plant, the bacteria can shut down. It is hard work finding success.

Pierce’s disease has been the limiting factor in bunch grape production in Florida. Symptoms include a general loss in plant strength, followed by death of the vine. Different species of grapes have a range of tolerance to Pierce’s disease. High vulnerability of premium wine grapes has practically eliminated the possibility of a wine industry in Florida.


DISEASE SYMPTOMS
  • Delayed leafing in the spring
  • Shoot dwarfing
  • Marginal scalding of leaves
  • Leaf mottling and interveinal chlorosis and necrosis
  • Wilting and premature coloring of fruit
  • Uneven maturity of canes
  • Eventual death of the root system
  • From IFAS Database (EDIS)
CAUSAL AGENT
  • A fastidious bacterium, Xyllella fastidiosa
HOST RANGE
  • Grape
GEOGRAPHIC DISTRIBUTION
  • Southeastern United States
  • California
  • Southern Ontario
SPREAD OF THE PATHOGEN AND CONTROL OPTIONS
  • Spread by leafhoppers known as sharpshooters
  • Control options: none
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