Master Gardener General Plant Pathology Talk

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General Master Gardener Training Plant Diseases
Brian D. Hudelson Department of Plant
Pathology University of Wisconsin-Madison/Extensio
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesThe Disease Triangle
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Susceptible Host
Favorable Environment
Pathogen
? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesCauses of Plant Diseases
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• Fungi
• Bacteria
• Viruses
• Nematodes
• Phytoplasmas
• Abiotic factors

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesFungi
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• Largest pathogen group
• More than 8000 pathogenic species
• Can be seen with the naked eye
• Vegetative growth through production of
  multicellular fungal threads (hyphae)
• Reproduce via spores

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesBacteria
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• About 200 pathogenic species
• Can be seen with a light microscope
• Simple, unicellular
• Reproduce by binary fission

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesViruses
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• Can only be seen using an electron microscope
• Extremely simple - nucleic acid with a protein
  coat
• Reproduce by taking over host reproductive
  machinery
• Often associated with insect vectors

? 1999 by the Board of Regents of the University
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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University of Wisconsin Extension
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University of Wisconsin Extension
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesPhytoplasmas
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• Funky bacteria
• Small, wall-less
• Phloem limited
• Usually seen only with an electron microscope
• Reproduce by binary fission
• Transmitted by insects (leafhoppers)

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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Plant DiseasesNematodes
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• Parasitic worms
• Very complex compared to other pathogens
• Usually seen only with a light microscope
• Reproduce by eggs

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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Plant DiseasesAbiotic Factors
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• Nutritional abnormalities
• Pesticide exposure
• Environmental pollutants
• Adverse weather conditions

? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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University of Wisconsin Extension
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University of Wisconsin Extension
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? 1999 by the Board of Regents of the University
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division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesCultural Control
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• Avoid pathogens
• Buy seed from a reputable source
• Inspect plants prior to purchase for above and
  below ground pathogens/diseases
• Inspect plants for insect pests
• Control alternate hosts
• Use non-contaminated water

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesCultural Control
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• Avoid conducive environmental conditions
• Moderate soil moisture
• Reduce humidity
• Have balanced nutrition
• Prevent water/heat stress
• Be aware of activities surrounding your plants

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesCultural Control
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• Sanitation
• Disinfest tools
• Adequately clean pots and benches
• Pasteurize soil prior to use
• Decontaminate recycled water
• Remove diseased plants promptly
• Remove senescent plant parts promptly

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesChemical Control
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• Protectant fungicides/bactericides
• Systemic fungicides/bactericides
• Fumigants

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesChemical Control
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• Use registered/labeled materials only
• Use products safely
• Get training

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesBiological Control
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• Disease resistance
• Biological pesticides
• Plant extracts
• Antagonistic microorganisms

? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesWhere to Go for Help
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Plant Disease Diagnostics Clinic Department of
Plant Pathology University of Wisconsin-Madison 16
30 Linden Drive Madison, WI 53706-1598 (608)
262-2863 bdh_at_plantpath.wisc.edu http//www.plantpa
th.wisc.edu/pddc
? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension
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Plant DiseasesWhere to Go for Help
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Soil and Plant Analysis Laboratory 5711 Mineral
Point Road Madison, WI 53705 (608)
262-4364 http//uwlab.soils.wisc.edu
? 1999 by the Board of Regents of the University
of Wisconsin System doing business as the
division of Cooperative Extension of the
University of Wisconsin Extension