PCA Plant Pathogens Exam | Agricultural Certification & Study Guide
Plant disease - (answer)Abnormal physiological processes caused by a causal pathogen
What is the economical significance of plant disease - (answer)Losses of yields, crops, inputs, and land
Pathogen - (answer)a causal agent of the disease
Disease - (answer)an abnormal condition that causes issues like declined health or death of a plant
Sign - (answer)the presence of a structure of a pathogen (spore, mycelium, or even mold growth)
Symptom - (answer)a plant response to a pathogen infection (decline of growth, vigor, or even death)
What are some abiotic factors that cause plant diseases - (answer)
What are some biotic factors that cause plant diseases - (answer)
Obligate parasite - (answer)Unable to grow outside of a living host (viruses)
Facultative saprophytes - (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 - (answer)a pathogen that prefers dead inorganic material, but can also obtain
nourishment from living organic material (bacteria)
Biotrophic - (answer)Any parasite that cannot survive in a dead host and therefore keeps it alive
Necrotrophic - (answer)parasites that kill the host cells
,PCA Plant Pathogens Exam | Agricultural Certification & Study Guide
Kotch postulates - (answer)A series or guidelines used to identify the microorganism that causes a
specific disease
What are the three components of plant disease triangle - (answer)the environment, the host, and the
causal agent
What is the role of each of the component of the disease triangle - (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 - (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 - (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 - (answer)alter planting dates,
remove alternative host, alter harvest dates
How can you break the host portion of the disease triangle - (answer)alternate crop, plant host
resistance species
How can you break the causal agent portion of the disease triangle - (answer)Pesticide application
How does the disease triangle help in diagnosis - (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 - (answer)Branch of medical science concerned with the incidence, distribution, and
control of disease that affect large numbers of people or hosts
, PCA Plant Pathogens Exam | Agricultural Certification & Study Guide
List the environmental factors that affect epidemics and explain how they do so - (answer)Temperature,
humidity, moisture, soil pH, nutrient availability, and air movement
Describe the importance of time in the development of an epidemic - (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 - (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 - (answer)conditions that increase
dissemination will accelerate development of epidemics
Single (annual) cycle (monocyclic disease - (answer)Diseases that only have a primary infection cycle
multiple cycle (polycyclic) disease - (answer)Disease that produce a secondary inoculum, and has a
secondary infection cycle in addition to the primary infection cycle
Why are single cycle disease less likely to develop into epidemics - (answer)Controlling a primary
inoculum is much easier than controlling primary and secondary inoculum. Once a primary inoculum is
controlled as well as the dissemination, the disease essentially stops developing
How do sanitation practice impact single cycle diseases - (answer)Epidemic may be delayed, but severe
epidemic can still occur if environmental conditions are favorable for disease development
How do sanitation practice impact multiple cycle diseases - (answer)reducing primary inoculum may
reduce the amount of secondary inoculum produced. If the 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
Plant disease - (answer)Abnormal physiological processes caused by a causal pathogen
What is the economical significance of plant disease - (answer)Losses of yields, crops, inputs, and land
Pathogen - (answer)a causal agent of the disease
Disease - (answer)an abnormal condition that causes issues like declined health or death of a plant
Sign - (answer)the presence of a structure of a pathogen (spore, mycelium, or even mold growth)
Symptom - (answer)a plant response to a pathogen infection (decline of growth, vigor, or even death)
What are some abiotic factors that cause plant diseases - (answer)
What are some biotic factors that cause plant diseases - (answer)
Obligate parasite - (answer)Unable to grow outside of a living host (viruses)
Facultative saprophytes - (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 - (answer)a pathogen that prefers dead inorganic material, but can also obtain
nourishment from living organic material (bacteria)
Biotrophic - (answer)Any parasite that cannot survive in a dead host and therefore keeps it alive
Necrotrophic - (answer)parasites that kill the host cells
,PCA Plant Pathogens Exam | Agricultural Certification & Study Guide
Kotch postulates - (answer)A series or guidelines used to identify the microorganism that causes a
specific disease
What are the three components of plant disease triangle - (answer)the environment, the host, and the
causal agent
What is the role of each of the component of the disease triangle - (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 - (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 - (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 - (answer)alter planting dates,
remove alternative host, alter harvest dates
How can you break the host portion of the disease triangle - (answer)alternate crop, plant host
resistance species
How can you break the causal agent portion of the disease triangle - (answer)Pesticide application
How does the disease triangle help in diagnosis - (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 - (answer)Branch of medical science concerned with the incidence, distribution, and
control of disease that affect large numbers of people or hosts
, PCA Plant Pathogens Exam | Agricultural Certification & Study Guide
List the environmental factors that affect epidemics and explain how they do so - (answer)Temperature,
humidity, moisture, soil pH, nutrient availability, and air movement
Describe the importance of time in the development of an epidemic - (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 - (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 - (answer)conditions that increase
dissemination will accelerate development of epidemics
Single (annual) cycle (monocyclic disease - (answer)Diseases that only have a primary infection cycle
multiple cycle (polycyclic) disease - (answer)Disease that produce a secondary inoculum, and has a
secondary infection cycle in addition to the primary infection cycle
Why are single cycle disease less likely to develop into epidemics - (answer)Controlling a primary
inoculum is much easier than controlling primary and secondary inoculum. Once a primary inoculum is
controlled as well as the dissemination, the disease essentially stops developing
How do sanitation practice impact single cycle diseases - (answer)Epidemic may be delayed, but severe
epidemic can still occur if environmental conditions are favorable for disease development
How do sanitation practice impact multiple cycle diseases - (answer)reducing primary inoculum may
reduce the amount of secondary inoculum produced. If the 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
