PCA Exam: Plant Pathogens Latest 2026 Actual
Complete Questions and Verified Answers|
Graded A+( 100% Guaranteed Pass)
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
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
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
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 -
Complete Questions and Verified Answers|
Graded A+( 100% Guaranteed Pass)
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
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
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
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 -
