Downy Mildew

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Downy Mildew

• Robert Fairchild
• VWT 35

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Introduction

• Serious grape pest since mid-1800s.
• Prevalent in warm areas with early spring
  rains/high humidity
• Economic impact depends on the grape growing
  region.
• Plasmopara viticola

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Description of Pest/Weakness

• Over-winters as Oospores in moist soil.
• May over-winter as mycelium in buds or leaves
  that persist through winter.
• Requires water for initial spread

Photo from http//stcoemgen.com/2013/06/03/downy
-mildew-2/
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Biology of Pest

• Disease Cycle

Photo courtesy of http//maryam2230.blogfa.com/pos
t-91.aspx
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Damage Caused/Monitoring

• Symptoms

• Signs

Photos of my Cabernet Sauvignon
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Management

• Cultural Control
• sanitation
• Mechanical and Physical
• None identified
• Biological
• None identified
• Chemical
• Bordeaux blend (Cu S blend)

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References

• Bettiga, L.J. (Ed.). (2013). Grape Pest
  Management, (3rd Ed.). Berkeley University of
  California Press.
• Dicklow, M.B., (2013). Downy Mildews of
  Ornamental Plants. Retrieved on 4/22/2014 from
  https//extension.umass.edu/floriculture/fact-shee
  ts/downy-mildews-ornamental-plants
• Evert, R.F. and Eichhorn, S.E., (2013). Raven
  Biology of Plants, (8th Ed.) New York W. H.
  Freeman and Company.
• Hoffman, U., (2008). "Optimization of downy
  mildew (Plasmopara viticola) control "in organic
  viticulture with low copper doses, new copper
  formulations and plant strengtheners, results of
  20 years of on farm research"- In Proceedings of
  Ecosostenible-wine INCAVI - Jornades techniques
  internationals - Villafranca Penedes
• Ontario Ministry of Agriculture and Food staff,
  (2012). Publication 370 - Guide to Greenhouse
  Floriculture Production Chapter 8 - Major
  Greenhouse Diseases. Retrieved on 4/20/2014 from
  http//www.omafra.gov.on.ca/english/crops/pub370/p
  ub370ch8.htmfig84.
• Winkler, A.J., Cook, J.A., Kliewer, W.M.,
  Lider, L.A. (1974). General Viticulture.
  Berkeley University of California Press.

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Questions?