PCA PLANT PATHOGENS EXAM NEWEST 2025
COMPLETE 100 QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED
A+
Plant Disease Definition - answer..Abnormal physiological processes caused by a
causal pathogen
Economic significance of plant diseases - answer..Losses of yield, crops, inputs, land
Pathogen - answer..Causal agent of disease
Signs of disease - answer..Structures of the pathogen
Symptoms of disease - answer..Plant response to pathogen infection
Abiotic factors of plant disease - answer..Air pollution, temperature, nutrients
Biotic factors of plant disease - answer..Living organisms (fungi, bacteria, viruses)
Obligate parasite - answer..unable to grow outside of a living host
Facultative saprophyte - answer..prefers living organic matter as a source of nutrition
but can adapt to the use of dead organic matter under certain conditions
Facultative parasite - answer..A pathogen that prefers dead inorganic material, but can
also obtain nourishment from living organic material
Biotroph - answer..Any parasite that cannot survive in a dead host and therefore keeps
it alive
Necrotroph - answer..Parasite that kills host cells
Koch's Postulates - answer..series of guidelines used to identify the microorganism that
causes a specific disease
Three components of disease triangle - answer..Causal agent, environment, host
,Role of each component of disease triangle - answer..All three must be present for
disease to occur. Environment must favor causal agent. Host must favor causal agent.
How humans impact each component of disease triangle - answer..Manipulate the
environment, host-plant resistance, preventative/suppressive/erradicative pesticides
Impact of epidemic when one component of disease triangle does not come into contact
with the other two components - answer..Slows epidemic to a halt. Disease spread
needs all three components interacting
Management strategy to break environment component - answer..Alter planting dates,
remove alternative hosts, alter harvest
Management strategy to break host component - answer..Alternate crop, host-plant
resistance
Management strategy to break causal agent component - answer..Pesticide applications
How can knowledge of plant disease triangle be used in diagnosis? - answer..Can rule
out different pathogens based on host and environment.
Epidemiology - answer..Branch of medical science concerned with the incidence,
distribution, and control of diseases that affect large numbers of people.
Environmental factors that affect epidemics - answer..Temperature, humidity, moisture,
soil pH, nutrient availability, air movement
Importance of time in the development of an epidemic - answer..Epidemics develop very
quickly if conditions are favorable. It is critical to reduce the rate of infection during
susceptible life stages of the plant
How does type of reproduction cycle affect development of an epidemic -
answer..Polycyclic epidemics can develop much more rapidly than monocyclic
epidemics because of secondary inoculum production.
How does dissemination affect development of an epidemic - answer..Conditions that
increase dissemination will accelerate development of epidemics
Monocyclic disease - answer..Disease that only has a primary infection cycle
Polycyclic disease - answer..Disease that produces a secondary inoculum, and has a
secondary infection cycle in addition to a primary infection cycle
, Why are monocyclic diseases less likely to result in serious epidemics? -
answer..Controlling primary inoculum is much easier than controlling primary and
secondary inoculum. Once primary inoculum is controlled and dissemination is
controlled, the disease essentially stops developing.
How do sanitation practices impact monocyclic diseases? - answer..Epidemic may be
delayed, but severe epidemic can still occur if environmental conditions are favorable
for disease development
How do sanitation practices impact polycyclic diseases? - answer..Reducing primary
inoculum may reduce the amount of secondary inoculum produced. If rate of infection is
high, there is little effect. But if rate of infection is low, it may reduce an epidemic
Formae specialis - answer..Indicates a fungus is adapted to a specific host
Incubation period - answer..interval between initial infection and first signs and
symptoms
Infection - answer..Invasion of a plant by a pathogen
Infestation - answer..Large numbers of pathogen present causing damage
Inoculum - answer..Infecting agent of a pathogen
Latent infection - answer..infection in which the infectious agent is present but not
causing symptoms
Mummy - answer..Dead, shriveled fruit that a pathogen may overwinter in
Overwintering - answer..the process by which some organisms pass through or wait out
the winter season
Armillaria sp. - answer..Oak root fungus
Oak root fungus class - answer..Basidiomycetes
Oak root fungus biology - answer..biotroph
Oak root fungus life cycle - answer..Sexual structure: basidiospores from mushrooms
Asexual structure: n/a
Survival stage: mycelium
Host: grapes, walnuts, pears
COMPLETE 100 QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED
A+
Plant Disease Definition - answer..Abnormal physiological processes caused by a
causal pathogen
Economic significance of plant diseases - answer..Losses of yield, crops, inputs, land
Pathogen - answer..Causal agent of disease
Signs of disease - answer..Structures of the pathogen
Symptoms of disease - answer..Plant response to pathogen infection
Abiotic factors of plant disease - answer..Air pollution, temperature, nutrients
Biotic factors of plant disease - answer..Living organisms (fungi, bacteria, viruses)
Obligate parasite - answer..unable to grow outside of a living host
Facultative saprophyte - answer..prefers living organic matter as a source of nutrition
but can adapt to the use of dead organic matter under certain conditions
Facultative parasite - answer..A pathogen that prefers dead inorganic material, but can
also obtain nourishment from living organic material
Biotroph - answer..Any parasite that cannot survive in a dead host and therefore keeps
it alive
Necrotroph - answer..Parasite that kills host cells
Koch's Postulates - answer..series of guidelines used to identify the microorganism that
causes a specific disease
Three components of disease triangle - answer..Causal agent, environment, host
,Role of each component of disease triangle - answer..All three must be present for
disease to occur. Environment must favor causal agent. Host must favor causal agent.
How humans impact each component of disease triangle - answer..Manipulate the
environment, host-plant resistance, preventative/suppressive/erradicative pesticides
Impact of epidemic when one component of disease triangle does not come into contact
with the other two components - answer..Slows epidemic to a halt. Disease spread
needs all three components interacting
Management strategy to break environment component - answer..Alter planting dates,
remove alternative hosts, alter harvest
Management strategy to break host component - answer..Alternate crop, host-plant
resistance
Management strategy to break causal agent component - answer..Pesticide applications
How can knowledge of plant disease triangle be used in diagnosis? - answer..Can rule
out different pathogens based on host and environment.
Epidemiology - answer..Branch of medical science concerned with the incidence,
distribution, and control of diseases that affect large numbers of people.
Environmental factors that affect epidemics - answer..Temperature, humidity, moisture,
soil pH, nutrient availability, air movement
Importance of time in the development of an epidemic - answer..Epidemics develop very
quickly if conditions are favorable. It is critical to reduce the rate of infection during
susceptible life stages of the plant
How does type of reproduction cycle affect development of an epidemic -
answer..Polycyclic epidemics can develop much more rapidly than monocyclic
epidemics because of secondary inoculum production.
How does dissemination affect development of an epidemic - answer..Conditions that
increase dissemination will accelerate development of epidemics
Monocyclic disease - answer..Disease that only has a primary infection cycle
Polycyclic disease - answer..Disease that produces a secondary inoculum, and has a
secondary infection cycle in addition to a primary infection cycle
, Why are monocyclic diseases less likely to result in serious epidemics? -
answer..Controlling primary inoculum is much easier than controlling primary and
secondary inoculum. Once primary inoculum is controlled and dissemination is
controlled, the disease essentially stops developing.
How do sanitation practices impact monocyclic diseases? - answer..Epidemic may be
delayed, but severe epidemic can still occur if environmental conditions are favorable
for disease development
How do sanitation practices impact polycyclic diseases? - answer..Reducing primary
inoculum may reduce the amount of secondary inoculum produced. If rate of infection is
high, there is little effect. But if rate of infection is low, it may reduce an epidemic
Formae specialis - answer..Indicates a fungus is adapted to a specific host
Incubation period - answer..interval between initial infection and first signs and
symptoms
Infection - answer..Invasion of a plant by a pathogen
Infestation - answer..Large numbers of pathogen present causing damage
Inoculum - answer..Infecting agent of a pathogen
Latent infection - answer..infection in which the infectious agent is present but not
causing symptoms
Mummy - answer..Dead, shriveled fruit that a pathogen may overwinter in
Overwintering - answer..the process by which some organisms pass through or wait out
the winter season
Armillaria sp. - answer..Oak root fungus
Oak root fungus class - answer..Basidiomycetes
Oak root fungus biology - answer..biotroph
Oak root fungus life cycle - answer..Sexual structure: basidiospores from mushrooms
Asexual structure: n/a
Survival stage: mycelium
Host: grapes, walnuts, pears
