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PCA - PLANT PATHOGENS EXAM 2025 |
ACTUAL EXAM QUESTIONS & ANSWERS
Plant Disease Definition -correct-answer-Abnormal physiological processes caused
by a causal pathogen
Economic significance of plant diseases -correct-answer-Losses of yield, crops,
inputs, land
Pathogen -correct-answer-Causal agent of disease
Signs of disease -correct-answer-Structures of the pathogen
Symptoms of disease -correct-answer-Plant response to pathogen infection
Abiotic factors of plant disease -correct-answer-Air pollution, temperature,
nutrients
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Biotic factors of plant disease -correct-answer-Living organisms (fungi, bacteria,
viruses)
Obligate parasite -correct-answer-unable to grow outside of a living host
Facultative saprophyte -correct-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 -correct-answer-A pathogen that prefers dead inorganic
material, but can also obtain nourishment from living organic material
Biotroph -correct-answer-Any parasite that cannot survive in a dead host and
therefore keeps it alive
Necrotroph -correct-answer-Parasite that kills host cells
Koch's Postulates -correct-answer-series of guidelines used to identify the
microorganism that causes a specific disease
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Three components of disease triangle -correct-answer-Causal agent, environment,
host
Role of each component of disease triangle -correct-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 -correct-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 -correct-answer-Slows epidemic to a halt.
Disease spread needs all three components interacting
Management strategy to break environment component -correct-answer-Alter
planting dates, remove alternative hosts, alter harvest
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Management strategy to break host component -correct-answer-Alternate crop,
host-plant resistance
Management strategy to break causal agent component -correct-answer-Pesticide
applications
How can knowledge of plant disease triangle be used in diagnosis? -correct-
answer-Can rule out different pathogens based on host and environment.
Epidemiology -correct-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 -correct-answer-Temperature,
humidity, moisture, soil pH, nutrient availability, air movement
Importance of time in the development of an epidemic -correct-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
PCA - PLANT PATHOGENS EXAM 2025 |
ACTUAL EXAM QUESTIONS & ANSWERS
Plant Disease Definition -correct-answer-Abnormal physiological processes caused
by a causal pathogen
Economic significance of plant diseases -correct-answer-Losses of yield, crops,
inputs, land
Pathogen -correct-answer-Causal agent of disease
Signs of disease -correct-answer-Structures of the pathogen
Symptoms of disease -correct-answer-Plant response to pathogen infection
Abiotic factors of plant disease -correct-answer-Air pollution, temperature,
nutrients
,2|Page
Biotic factors of plant disease -correct-answer-Living organisms (fungi, bacteria,
viruses)
Obligate parasite -correct-answer-unable to grow outside of a living host
Facultative saprophyte -correct-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 -correct-answer-A pathogen that prefers dead inorganic
material, but can also obtain nourishment from living organic material
Biotroph -correct-answer-Any parasite that cannot survive in a dead host and
therefore keeps it alive
Necrotroph -correct-answer-Parasite that kills host cells
Koch's Postulates -correct-answer-series of guidelines used to identify the
microorganism that causes a specific disease
,3|Page
Three components of disease triangle -correct-answer-Causal agent, environment,
host
Role of each component of disease triangle -correct-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 -correct-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 -correct-answer-Slows epidemic to a halt.
Disease spread needs all three components interacting
Management strategy to break environment component -correct-answer-Alter
planting dates, remove alternative hosts, alter harvest
, 4|Page
Management strategy to break host component -correct-answer-Alternate crop,
host-plant resistance
Management strategy to break causal agent component -correct-answer-Pesticide
applications
How can knowledge of plant disease triangle be used in diagnosis? -correct-
answer-Can rule out different pathogens based on host and environment.
Epidemiology -correct-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 -correct-answer-Temperature,
humidity, moisture, soil pH, nutrient availability, air movement
Importance of time in the development of an epidemic -correct-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
