PCA - Plant Pathogens Exam 2026 Question
and Answer | Final Review Pack | Grade A+
• Pathogen. CORRECT ANSWER: a causal agent of the disease
• Disease. CORRECT ANSWER: an abnormal condition that causes
issues like declined health or death of a plant
• Sign. CORRECT ANSWER: the presence of a structure of a pathogen
(spore, mycelium, or even mold growth)
• Symptom. CORRECT ANSWER: a plant response to a pathogen
infection (decline of growth, vigor, or even death)
• What are some abiotic factors that cause plant diseases. CORRECT
ANSWER:
• What are some biotic factors that cause plant diseases. CORRECT
ANSWER:
• Obligate parasite. CORRECT ANSWER: Unable to grow outside of a
living host (viruses)
• Facultative saprophytes. CORRECT ANSWER: prefers living organic
matter as a source of nutrition but can adapt to the use of dead organic
matter under certain conditions (phytophthora)
• Facultative parasites. CORRECT ANSWER: a pathogen that prefers
dead inorganic material, but can also obtain nourishment from living
organic material (bacteria)
• Biotrophic. CORRECT ANSWER: Any parasite that cannot survive in
a dead host and therefore keeps it alive
,• Necrotrophic. CORRECT ANSWER: parasites that kill the host cells
• Kotch postulates. CORRECT ANSWER: A series or guidelines used to
identify the microorganism that causes a specific disease
• What are the three components of plant disease triangle. CORRECT
ANSWER: the environment, the host, and the causal agent
• What is the role of each of the component of the disease triangle.
CORRECT ANSWER: All three must be present in order for infection
to take place, the environment must favor the causal agent and the host
must be susceptible to the causal agent
• How do humans impact the disease triangle. CORRECT ANSWER:
Humans can manipulate the environment, plant host resistant varieties,
and use preventative/suppressive/eradicative pesticides all to change a
piece of the disease triangle
• How does one component of the triangle impact a epidemic if it does
not come into contact with the other two. CORRECT ANSWER: If one
component of the plant disease triangle is missing the epidemic will
slow to a halt, in order for the disease to spread it must have all three
parts of the triangle
• How can you break the environment portion of the disease triangle.
CORRECT ANSWER: alter planting dates, remove alternative host,
alter harvest dates
• How can you break the host portion of the disease triangle. CORRECT
ANSWER: alternate crop, plant host resistance species
• How can you break the causal agent portion of the disease triangle.
CORRECT ANSWER: Pesticide application
, • How does the disease triangle help in diagnosis. CORRECT
ANSWER: If you understand the plant disease triangle you can use the
host species and environment of a area where the crop is planted to rule
out different pathogens
• Epidemiology. CORRECT ANSWER: Branch of medical science
concerned with the incidence, distribution, and control of disease that
affect large numbers of people or hosts
• List the environmental factors that affect epidemics and explain how
they do so. CORRECT ANSWER: Temperature, humidity, moisture,
soil pH, nutrient availability, and air movement
• Describe the importance of time in the development of an epidemic.
CORRECT ANSWER: Epidemics develop quickly if conditions are
favorable. It is critical to reduce the rate of infection during susceptible
life stages of the plant
• How does type reproduction affect the development of an epidemic.
CORRECT ANSWER: polycyclic epidemics can develop much more
rapidly than monocyclic epidemics because of secondary inoculum
production
• How does dissemination affect the development of an epidemic.
CORRECT ANSWER: conditions that increase dissemination will
accelerate development of epidemics
• Single (annual) cycle (monocyclic disease. CORRECT ANSWER:
Diseases that only have a primary infection cycle
• multiple cycle (polycyclic) disease. CORRECT ANSWER: Disease
that produce a secondary inoculum, and has a secondary infection cycle
in addition to the primary infection cycle
and Answer | Final Review Pack | Grade A+
• Pathogen. CORRECT ANSWER: a causal agent of the disease
• Disease. CORRECT ANSWER: an abnormal condition that causes
issues like declined health or death of a plant
• Sign. CORRECT ANSWER: the presence of a structure of a pathogen
(spore, mycelium, or even mold growth)
• Symptom. CORRECT ANSWER: a plant response to a pathogen
infection (decline of growth, vigor, or even death)
• What are some abiotic factors that cause plant diseases. CORRECT
ANSWER:
• What are some biotic factors that cause plant diseases. CORRECT
ANSWER:
• Obligate parasite. CORRECT ANSWER: Unable to grow outside of a
living host (viruses)
• Facultative saprophytes. CORRECT ANSWER: prefers living organic
matter as a source of nutrition but can adapt to the use of dead organic
matter under certain conditions (phytophthora)
• Facultative parasites. CORRECT ANSWER: a pathogen that prefers
dead inorganic material, but can also obtain nourishment from living
organic material (bacteria)
• Biotrophic. CORRECT ANSWER: Any parasite that cannot survive in
a dead host and therefore keeps it alive
,• Necrotrophic. CORRECT ANSWER: parasites that kill the host cells
• Kotch postulates. CORRECT ANSWER: A series or guidelines used to
identify the microorganism that causes a specific disease
• What are the three components of plant disease triangle. CORRECT
ANSWER: the environment, the host, and the causal agent
• What is the role of each of the component of the disease triangle.
CORRECT ANSWER: All three must be present in order for infection
to take place, the environment must favor the causal agent and the host
must be susceptible to the causal agent
• How do humans impact the disease triangle. CORRECT ANSWER:
Humans can manipulate the environment, plant host resistant varieties,
and use preventative/suppressive/eradicative pesticides all to change a
piece of the disease triangle
• How does one component of the triangle impact a epidemic if it does
not come into contact with the other two. CORRECT ANSWER: If one
component of the plant disease triangle is missing the epidemic will
slow to a halt, in order for the disease to spread it must have all three
parts of the triangle
• How can you break the environment portion of the disease triangle.
CORRECT ANSWER: alter planting dates, remove alternative host,
alter harvest dates
• How can you break the host portion of the disease triangle. CORRECT
ANSWER: alternate crop, plant host resistance species
• How can you break the causal agent portion of the disease triangle.
CORRECT ANSWER: Pesticide application
, • How does the disease triangle help in diagnosis. CORRECT
ANSWER: If you understand the plant disease triangle you can use the
host species and environment of a area where the crop is planted to rule
out different pathogens
• Epidemiology. CORRECT ANSWER: Branch of medical science
concerned with the incidence, distribution, and control of disease that
affect large numbers of people or hosts
• List the environmental factors that affect epidemics and explain how
they do so. CORRECT ANSWER: Temperature, humidity, moisture,
soil pH, nutrient availability, and air movement
• Describe the importance of time in the development of an epidemic.
CORRECT ANSWER: Epidemics develop quickly if conditions are
favorable. It is critical to reduce the rate of infection during susceptible
life stages of the plant
• How does type reproduction affect the development of an epidemic.
CORRECT ANSWER: polycyclic epidemics can develop much more
rapidly than monocyclic epidemics because of secondary inoculum
production
• How does dissemination affect the development of an epidemic.
CORRECT ANSWER: conditions that increase dissemination will
accelerate development of epidemics
• Single (annual) cycle (monocyclic disease. CORRECT ANSWER:
Diseases that only have a primary infection cycle
• multiple cycle (polycyclic) disease. CORRECT ANSWER: Disease
that produce a secondary inoculum, and has a secondary infection cycle
in addition to the primary infection cycle
