PCA - Plant Pathogens Exam Ques ons and answers
Newest Rated A+ 2025/2026 NEW!! UPDATED
Plant Disease Defini on - CORRECT ANSWERS Abnormal physiological processes caused by a
causal pathogen
Economic significance of plant diseases - CORRECT ANSWERS Losses of yield, crops, inputs,
land
Pathogen - CORRECT ANSWERS Causal agent of disease
Signs of disease - CORRECT ANSWERS Structures of the pathogen
Symptoms of disease - CORRECT ANSWERS Plant response to pathogen infec on
Abio c factors of plant disease - CORRECT ANSWERS Air pollu on, temperature, nutrients
Bio c factors of plant disease - CORRECT ANSWERS Living organisms (fungi, bacteria, viruses)
Obligate parasite - CORRECT ANSWERS unable to grow outside of a living host
Faculta ve saprophyte - CORRECT ANSWERS prefers living organic ma+er as a source of
nutri on but can adapt to the use of dead organic ma+er under certain condi ons
Faculta ve parasite - CORRECT ANSWERS A pathogen that prefers dead inorganic material,
but can also obtain nourishment from living organic material
, Biotroph - CORRECT ANSWERS Any parasite that cannot survive in a dead host and therefore
keeps it alive
Necrotroph - CORRECT ANSWERS Parasite that kills host cells
Koch's Postulates - CORRECT ANSWERS series of guidelines used to iden fy the
microorganism that causes a specific disease
Three components of disease triangle - CORRECT ANSWERS Causal agent, environment, host
Role of each component of disease triangle - CORRECT ANSWERS 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 ANSWERS Manipulate
the environment, host-plant resistance, preventa ve/suppressive/erradica ve pes cides
Impact of epidemic when one component of disease triangle does not come into contact with
the other two components - CORRECT ANSWERS Slows epidemic to a halt. Disease spread
needs all three components interac ng
Management strategy to break environment component - CORRECT ANSWERS Alter plan ng
dates, remove alterna ve hosts, alter harvest
Management strategy to break host component - CORRECT ANSWERS Alternate crop, host-
plant resistance
Management strategy to break causal agent component - CORRECT ANSWERS Pes cide
applica ons
, How can knowledge of plant disease triangle be used in diagnosis? - CORRECT ANSWERS Can
rule out different pathogens based on host and environment.
Epidemiology - CORRECT ANSWERS Branch of medical science concerned with the incidence,
distribu on, and control of diseases that affect large numbers of people.
Environmental factors that affect epidemics - CORRECT ANSWERS Temperature, humidity,
moisture, soil pH, nutrient availability, air movement
Importance of me in the development of an epidemic - CORRECT ANSWERS Epidemics
develop very quickly if condi ons are favorable. It is cri cal to reduce the rate of infec on
during suscep ble life stages of the plant
How does type of reproduc on cycle affect development of an epidemic - CORRECT ANSWERS
Polycyclic epidemics can develop much more rapidly than monocyclic epidemics because of
secondary inoculum produc on.
How does dissemina on affect development of an epidemic - CORRECT ANSWERS Condi ons
that increase dissemina on will accelerate development of epidemics
Monocyclic disease - CORRECT ANSWERS Disease that only has a primary infec on cycle
Polycyclic disease - CORRECT ANSWERS Disease that produces a secondary inoculum, and has
a secondary infec on cycle in addi on to a primary infec on cycle
Why are monocyclic diseases less likely to result in serious epidemics? - CORRECT ANSWERS
Controlling primary inoculum is much easier than controlling primary and secondary inoculum.
Once primary inoculum is controlled and dissemina on is controlled, the disease essen ally
stops developing.
, How do sanita on prac ces impact monocyclic diseases? - CORRECT ANSWERS Epidemic may
be delayed, but severe epidemic can s ll occur if environmental condi ons are favorable for
disease development
How do sanita on prac ces impact polycyclic diseases? - CORRECT ANSWERS Reducing
primary inoculum may reduce the amount of secondary inoculum produced. If rate of infec on
is high, there is li+le effect. But if rate of infec on is low, it may reduce an epidemic
Formae specialis - CORRECT ANSWERS Indicates a fungus is adapted to a specific host
Incuba on period - CORRECT ANSWERS interval between ini al infec on and first signs and
symptoms
Infec on - CORRECT ANSWERS Invasion of a plant by a pathogen
Infesta on - CORRECT ANSWERS Large numbers of pathogen present causing damage
Inoculum - CORRECT ANSWERS Infec ng agent of a pathogen
Latent infec on - CORRECT ANSWERS infec on in which the infec ous agent is present but
not causing symptoms
Mummy - CORRECT ANSWERS Dead, shriveled fruit that a pathogen may overwinter in
Overwintering - CORRECT ANSWERS the process by which some organisms pass through or
wait out the winter season
Newest Rated A+ 2025/2026 NEW!! UPDATED
Plant Disease Defini on - CORRECT ANSWERS Abnormal physiological processes caused by a
causal pathogen
Economic significance of plant diseases - CORRECT ANSWERS Losses of yield, crops, inputs,
land
Pathogen - CORRECT ANSWERS Causal agent of disease
Signs of disease - CORRECT ANSWERS Structures of the pathogen
Symptoms of disease - CORRECT ANSWERS Plant response to pathogen infec on
Abio c factors of plant disease - CORRECT ANSWERS Air pollu on, temperature, nutrients
Bio c factors of plant disease - CORRECT ANSWERS Living organisms (fungi, bacteria, viruses)
Obligate parasite - CORRECT ANSWERS unable to grow outside of a living host
Faculta ve saprophyte - CORRECT ANSWERS prefers living organic ma+er as a source of
nutri on but can adapt to the use of dead organic ma+er under certain condi ons
Faculta ve parasite - CORRECT ANSWERS A pathogen that prefers dead inorganic material,
but can also obtain nourishment from living organic material
, Biotroph - CORRECT ANSWERS Any parasite that cannot survive in a dead host and therefore
keeps it alive
Necrotroph - CORRECT ANSWERS Parasite that kills host cells
Koch's Postulates - CORRECT ANSWERS series of guidelines used to iden fy the
microorganism that causes a specific disease
Three components of disease triangle - CORRECT ANSWERS Causal agent, environment, host
Role of each component of disease triangle - CORRECT ANSWERS 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 ANSWERS Manipulate
the environment, host-plant resistance, preventa ve/suppressive/erradica ve pes cides
Impact of epidemic when one component of disease triangle does not come into contact with
the other two components - CORRECT ANSWERS Slows epidemic to a halt. Disease spread
needs all three components interac ng
Management strategy to break environment component - CORRECT ANSWERS Alter plan ng
dates, remove alterna ve hosts, alter harvest
Management strategy to break host component - CORRECT ANSWERS Alternate crop, host-
plant resistance
Management strategy to break causal agent component - CORRECT ANSWERS Pes cide
applica ons
, How can knowledge of plant disease triangle be used in diagnosis? - CORRECT ANSWERS Can
rule out different pathogens based on host and environment.
Epidemiology - CORRECT ANSWERS Branch of medical science concerned with the incidence,
distribu on, and control of diseases that affect large numbers of people.
Environmental factors that affect epidemics - CORRECT ANSWERS Temperature, humidity,
moisture, soil pH, nutrient availability, air movement
Importance of me in the development of an epidemic - CORRECT ANSWERS Epidemics
develop very quickly if condi ons are favorable. It is cri cal to reduce the rate of infec on
during suscep ble life stages of the plant
How does type of reproduc on cycle affect development of an epidemic - CORRECT ANSWERS
Polycyclic epidemics can develop much more rapidly than monocyclic epidemics because of
secondary inoculum produc on.
How does dissemina on affect development of an epidemic - CORRECT ANSWERS Condi ons
that increase dissemina on will accelerate development of epidemics
Monocyclic disease - CORRECT ANSWERS Disease that only has a primary infec on cycle
Polycyclic disease - CORRECT ANSWERS Disease that produces a secondary inoculum, and has
a secondary infec on cycle in addi on to a primary infec on cycle
Why are monocyclic diseases less likely to result in serious epidemics? - CORRECT ANSWERS
Controlling primary inoculum is much easier than controlling primary and secondary inoculum.
Once primary inoculum is controlled and dissemina on is controlled, the disease essen ally
stops developing.
, How do sanita on prac ces impact monocyclic diseases? - CORRECT ANSWERS Epidemic may
be delayed, but severe epidemic can s ll occur if environmental condi ons are favorable for
disease development
How do sanita on prac ces impact polycyclic diseases? - CORRECT ANSWERS Reducing
primary inoculum may reduce the amount of secondary inoculum produced. If rate of infec on
is high, there is li+le effect. But if rate of infec on is low, it may reduce an epidemic
Formae specialis - CORRECT ANSWERS Indicates a fungus is adapted to a specific host
Incuba on period - CORRECT ANSWERS interval between ini al infec on and first signs and
symptoms
Infec on - CORRECT ANSWERS Invasion of a plant by a pathogen
Infesta on - CORRECT ANSWERS Large numbers of pathogen present causing damage
Inoculum - CORRECT ANSWERS Infec ng agent of a pathogen
Latent infec on - CORRECT ANSWERS infec on in which the infec ous agent is present but
not causing symptoms
Mummy - CORRECT ANSWERS Dead, shriveled fruit that a pathogen may overwinter in
Overwintering - CORRECT ANSWERS the process by which some organisms pass through or
wait out the winter season
