PCA Exam Plant Pathogens Questions
Complete With Correct Answers
\Q\.Plant disease - ANSWERS✔-Abnormal physiological processes caused by a causal pathogen
\Q\.What is the economical significance of plant disease - ANSWERS✔-Losses of yields, crops,
inputs, and land
\Q\.Pathogen - ANSWERS✔-a causal agent of the disease
\Q\.Disease - ANSWERS✔-an abnormal condition that causes issues like declined health or
death of a plant
\Q\.Sign - ANSWERS✔-the presence of a structure of a pathogen (spore, mycelium, or even
mold growth)
\Q\.Symptom - ANSWERS✔-a plant response to a pathogen infection (decline of growth, vigor,
or even death)
\Q\.Obligate parasite - ANSWERS✔-Unable to grow outside of a living host (viruses)
\Q\.Facultative saprophytes - ANSWERS✔-prefers living organic matter as a source of nutrition
but can adapt to the use of dead organic matter under certain conditions (phytophthora)
,\Q\.Facultative parasites - ANSWERS✔-a pathogen that prefers dead inorganic material, but can
also obtain nourishment from living organic material (bacteria)
\Q\.Biotrophic - ANSWERS✔-Any parasite that cannot survive in a dead host and therefore
keeps it alive
\Q\.Necrotrophic - ANSWERS✔-parasites that kill the host cells
\Q\.Kotch postulates - ANSWERS✔-A series or guidelines used to identify the microorganism
that causes a specific disease
\Q\.What are the three components of plant disease triangle - ANSWERS✔-the environment,
the host, and the causal agent
\Q\.What is the role of each of the component of the disease triangle - ANSWERS✔-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
\Q\.How do humans impact the disease triangle - ANSWERS✔-Humans can manipulate the
environment, plant host resistant varieties, and use preventative/suppressive/eradicative
pesticides all to change a piece of the disease triangle
\Q\.How does one component of the triangle impact a epidemic if it does not come into contact
with the other two - ANSWERS✔-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
\Q\.How can you break the environment portion of the disease triangle - ANSWERS✔-alter
planting dates, remove alternative host, alter harvest dates
, \Q\.How can you break the host portion of the disease triangle - ANSWERS✔-alternate crop,
plant host resistance species
\Q\.How can you break the causal agent portion of the disease triangle - ANSWERS✔-Pesticide
application
\Q\.How does the disease triangle help in diagnosis - ANSWERS✔-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
\Q\.Epidemiology - ANSWERS✔-Branch of medical science concerned with the incidence,
distribution, and control of disease that affect large numbers of people or hosts
\Q\.List the environmental factors that affect epidemics and explain how they do so -
ANSWERS✔-Temperature, humidity, moisture, soil pH, nutrient availability, and air movement
\Q\.Describe the importance of time in the development of an epidemic - ANSWERS✔-
Epidemics develop quickly if conditions are favorable. It is critical to reduce the rate of infection
during susceptible life stages of the plant
\Q\.How does type reproduction affect the development of an epidemic - ANSWERS✔-
polycyclic epidemics can develop much more rapidly than monocyclic epidemics because of
secondary inoculum production
\Q\.How does dissemination affect the development of an epidemic - ANSWERS✔-conditions
that increase dissemination will accelerate development of epidemics
Complete With Correct Answers
\Q\.Plant disease - ANSWERS✔-Abnormal physiological processes caused by a causal pathogen
\Q\.What is the economical significance of plant disease - ANSWERS✔-Losses of yields, crops,
inputs, and land
\Q\.Pathogen - ANSWERS✔-a causal agent of the disease
\Q\.Disease - ANSWERS✔-an abnormal condition that causes issues like declined health or
death of a plant
\Q\.Sign - ANSWERS✔-the presence of a structure of a pathogen (spore, mycelium, or even
mold growth)
\Q\.Symptom - ANSWERS✔-a plant response to a pathogen infection (decline of growth, vigor,
or even death)
\Q\.Obligate parasite - ANSWERS✔-Unable to grow outside of a living host (viruses)
\Q\.Facultative saprophytes - ANSWERS✔-prefers living organic matter as a source of nutrition
but can adapt to the use of dead organic matter under certain conditions (phytophthora)
,\Q\.Facultative parasites - ANSWERS✔-a pathogen that prefers dead inorganic material, but can
also obtain nourishment from living organic material (bacteria)
\Q\.Biotrophic - ANSWERS✔-Any parasite that cannot survive in a dead host and therefore
keeps it alive
\Q\.Necrotrophic - ANSWERS✔-parasites that kill the host cells
\Q\.Kotch postulates - ANSWERS✔-A series or guidelines used to identify the microorganism
that causes a specific disease
\Q\.What are the three components of plant disease triangle - ANSWERS✔-the environment,
the host, and the causal agent
\Q\.What is the role of each of the component of the disease triangle - ANSWERS✔-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
\Q\.How do humans impact the disease triangle - ANSWERS✔-Humans can manipulate the
environment, plant host resistant varieties, and use preventative/suppressive/eradicative
pesticides all to change a piece of the disease triangle
\Q\.How does one component of the triangle impact a epidemic if it does not come into contact
with the other two - ANSWERS✔-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
\Q\.How can you break the environment portion of the disease triangle - ANSWERS✔-alter
planting dates, remove alternative host, alter harvest dates
, \Q\.How can you break the host portion of the disease triangle - ANSWERS✔-alternate crop,
plant host resistance species
\Q\.How can you break the causal agent portion of the disease triangle - ANSWERS✔-Pesticide
application
\Q\.How does the disease triangle help in diagnosis - ANSWERS✔-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
\Q\.Epidemiology - ANSWERS✔-Branch of medical science concerned with the incidence,
distribution, and control of disease that affect large numbers of people or hosts
\Q\.List the environmental factors that affect epidemics and explain how they do so -
ANSWERS✔-Temperature, humidity, moisture, soil pH, nutrient availability, and air movement
\Q\.Describe the importance of time in the development of an epidemic - ANSWERS✔-
Epidemics develop quickly if conditions are favorable. It is critical to reduce the rate of infection
during susceptible life stages of the plant
\Q\.How does type reproduction affect the development of an epidemic - ANSWERS✔-
polycyclic epidemics can develop much more rapidly than monocyclic epidemics because of
secondary inoculum production
\Q\.How does dissemination affect the development of an epidemic - ANSWERS✔-conditions
that increase dissemination will accelerate development of epidemics
