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SFR 457/557: Topic 4 - Tree Pests and Disease: Infectious Disease page
SFR 457/557 Tree Pests and Disease
Topic 4
Principles for Studying Infectious Diseases
(Edmonds et al. 2011 p. 199-211)
I.
Define
A.
B.
C.
II.
Infection
1.
Parasite
2.
Host
3.
Infection
Microbial parasites
1.
Fungi
2.
Bacteria
3.
Phytoplasmas
4.
Viruses
Infectious disease
The Pathogen Cycle (Disease Cycle).
A.
Latent period.
1.
Infection period a)
Inoculation (i)
Propagules -
(ii)
Portal of entry -
b)
Penetration.
c)
Establishment -
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SFR 457/557: Topic 4 - Tree Pests and Disease: Infectious Disease page
2.
Incubation period – colonization
3.
Symptom expression -
B.
Infectious period -
C.
Dissemination.
1.
III.
Vector.
D.
Virulence (pathogenicity) of microorganisms.
E.
Tree Resistance
1.
Dependent on genes -
2.
Has energy (vigor) -
Disease complex specific to infectious disease.
A.
Components of disease complex (disease triangle).
1.
2.
Pathogen(s):
a)
Latin name.
b)
Life cycle.
(i)
Vegetative -
(ii)
Reproductive -
(iii)
Disease products
Diseased host(s).
a)
Susceptible species:
b)
Symptoms:
(i)
Necrotic (a)
Leaf necrosis.
(b)
Tip dieback.
(c)
Stem cankers.
(d)
Vascular wilts.
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SFR 457/557: Topic 4 - Tree Pests and Disease: Infectious Disease page
(e)
Root diseases.
(f)
Mortality.
(ii)
Hypoplastic (a)
Energy drain.
(b)
Chlorosis.
(iii)
c)
3.
IV.
Hyperplastic - .
(a)
Galls.
(b)
Witch’s broom.
Diseased functions:
Distribution.
Koch's postulates - establish if an organism is a pathogen.
A.
Isolate from diseased tissue only.
B.
Inoculate.
C.
Symptoms.
D.
Re-isolate.
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SFR 457/557: Topic 4 - Tree Pests and Disease: Infectious Disease page
V.
VI.
Control
A.
Pathogen population dynamics
B.
Options
1.
Silvicultural -
2.
Biological -
3.
Breeding -
4.
Legal -
5.
Chemical -
6.
Mechanical - Sanitation - n
7.
Do nothing
Associations Among Organisms - Symbiosis.
A.
Interactions involving two species.
1.
2.
B.
Parasitic a)
Biotrophic -
b)
Necrotrophic -
Saprophytic -
Balance of interaction 1.
Mutualistic
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SFR 457/557: Topic 4 - Tree Pests and Disease: Infectious Disease page
C.
2.
Commensalistic.
3.
Pathogenic.
Facultative or obligate.
1.
2.
VII.
Facultative
a)
Interaction can vary
b)
Sometimes saprophytic
c)
Sometimes pathogenic
Obligate -
Terminology.
Biological control
Biotrophic
Breeding
Chemical Control
Commensalistic
Disease Cycle
Disease Triangle (Pyramid)
Dissemination
Establishment
Etiology
Facultative
Hyperplastic
Hypertrophic
Hypoplastic
Incubation period
Infection period
Infectious period
Inoculation
Inoculum
IPM
Koch's postulates
Latent period
Legal Control
Mechanical Control
Mutualistic
Necrotic
Necrotrophic
Obligate
Parasitic
Pathogen Cycle
Pathogenicity
Penetration
Quarantines
Resistance
Saprophytic
Signs
Silvicultural control
Susceptible
Symbiosis
Symptoms
Vector.
Virulence
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