Transcript Plant Diseases

Plant Pathology
David R. Drake
Pathology
The study of disease.
Disease
Anything that causes abnormal growth
Plant Disease
Any disturbance of a plant that interferes with its
normal growth and development, economic
value, and aesthetic quality;
a continuously, often progressively affected
condition in contrast to injury, which results
from momentary damage.
Source: Plant Diseases: Their Biology and
Social Impact. Gail L. Schumann APS Press
Historical Plant Diseases

Irish Potato Famine
 American Chestnut Blight
 Dutch Elm Disease.
 St. Anthony’s Fire
 Tulip Virus
St. Anthony’s Fire

Ergot
 Prevalent in Rye
Tulip Virus

Tulips introduced to Europe circa 1550
 Virus infected bulbs created Tulipmania
from 1634-37.
PRICE BARTERED FOR 1 BULB
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4 Tons Wheat
8 Tons Rye
4 Fat Oxen
8 Fat Pigs
12 Fat Sheep
2 Hogsheads Wine
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4 Barrels Beer
2 Barrels Butter
1000 Lbs Cheese
1 Bed with Accessories
1 Full-dress Suit
1 Silver Goblet
Types of Pathogens
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Parasitic
 Non-parasitic (abiotic)
Factors in Disease:
Disease Triangle
Environment
Pathogen
Host
Parasitic

Fungi
 Bacteria
 Virus
 Nematodes
 protoplasma
 Parasitic plants
Fungi

Lack cholorphyll
 100,100 – beneficial
 Most microscopic
 Spores
 Fungicides
Bacteria

Single-celled
 Binary fission
 Rapid multiplication
 Free moisture
 Bactericides
Virus

Protein and nucleic acid
 Sub-microscopic
 Insect vectored
 Mechanical transmission
Nematodes

Microscopic eel worms
 Eggs
 Stylet
 Virus vectors
 Nematicide
Protoplasma
(mycoplasma)

Similar to bacteria
 No cell wall
 Vectored by leafhoppers
 Controlled with antibiotics
Parasitic Plants
Dodder
Non-parasitic

Iron chlorosis
 Powdery mildew
 Cytospora
 Fire blight
Iron Chlorosis
Powdery Mildew

Halt (thiophanate methyl)
 Benlate
 Funginex
 Bayleton
 Sulfur
 Tilt
Funginex
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Roses
– Powdery mildew
– Rust (rare)
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Fruit
– Powdery mildew
– Brown rot (rare)
Cytospora
Canker
Fire Blight
Fire Blight Control
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Avoid excess nitrogen
 Prune out cankers
 Treat with fixed copper or streptomycin
Cuitlachoche
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Safflower oil
Onion chopped
Garlic chopped
Chilies
Cuitalchoche
Saute’ until translucent
3T
2T
2
4
4 Cups
Verticillium Wilt
Chlorothalonil
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Disease control with Daconil
 Daconil lawn and garden fungicide
 Daconil 2787
 Multi-purpose fungicide
White Mold
Slime Flux
Wet Wood