PCA PLANT PATHOGENS FINAL EXAM UPDATED
QUESTIONS AND ANSWERS RATED A+
✔✔Why are monocyclic diseases less likely to result in serious epidemics? -
✔✔Controlling primary inoculum is much easier than controlling primary and secondary
inoculum. Once primary inoculum is controlled and dissemination is controlled, the
disease essentially stops developing.
✔✔How do sanitation practices impact monocyclic diseases? - ✔✔Epidemic may be
delayed, but severe epidemic can still occur if environmental conditions are favorable
for disease development
✔✔How do sanitation practices impact polycyclic diseases? - ✔✔Reducing primary
inoculum may reduce the amount of secondary inoculum produced. If rate of infection is
high, there is little effect. But if rate of infection is low, it may reduce an epidemic
✔✔Formae specialis - ✔✔Indicates a fungus is adapted to a specific host
✔✔Incubation period - ✔✔interval between initial infection and first signs and symptoms
✔✔Infection - ✔✔Invasion of a plant by a pathogen
✔✔Infestation - ✔✔Large numbers of pathogen present causing damage
✔✔Inoculum - ✔✔Infecting agent of a pathogen
✔✔Latent infection - ✔✔infection in which the infectious agent is present but not
causing symptoms
✔✔Mummy - ✔✔Dead, shriveled fruit that a pathogen may overwinter in
✔✔Overwintering - ✔✔the process by which some organisms pass through or wait out
the winter season
✔✔Pathovar - ✔✔subdivision of a plant pathogenic bacterial species defined by host
range
✔✔Propagule - ✔✔Portion of a plant which is used to generate a new plant
✔✔Race - ✔✔Strain of a virus adapted to a specific host
✔✔Soil inhabitant/soil resident - ✔✔Pathogen that can survive in the soil for long
periods of time
,✔✔Soil transient/soil invader - ✔✔Pathogen that can survive in the soil for a short
period of time
✔✔Vector - ✔✔An organism that can transport and transmit a disease
✔✔Apothecium - ✔✔cup-shaped ascocarp
✔✔Ascocarp - ✔✔Fruiting body of an ascomycete
✔✔Ascospore - ✔✔sexual spores of ascomycete fungi that develop within an ascus
✔✔Basidiospore - ✔✔A sexual fungal spore produced in a basidium, characteristic of
the basidiomycetes
✔✔Chlamydospore - ✔✔a thick-walled, asexual, resistant spore; a survival spore
✔✔Cleistothecium - ✔✔Closed ascocarp, typical of powdery mildews, also known as
the Chasmothecium
✔✔Conidium - ✔✔an asexually produced fungal spore formed on a conidiophore,
produced in ascomycetes
✔✔Fungi Imperfecti - ✔✔large and heterogeneous form division of fungi comprising
forms for which no sexually reproductive stage is known, also known as
Deuteromycetes
✔✔Fungus - ✔✔Saprophytic and parasitic spore-producing eukaryotic organisms that
lack chlorophyll and include molds, rusts, mildews, smuts, mushrooms, and yeasts.
✔✔Haustorium (Haustoria) - ✔✔specialized hypha of parasitic fungi that grows into a
host's tissues and absorbs its nutrients
✔✔Hypha - ✔✔one of many long, slender filaments that makes up the body of a fungus
✔✔Mycelium - ✔✔densely branched network of the hyphae of a fungus
✔✔Oospore - ✔✔thick-walled, sexually derived resting spore of oomycetes
✔✔Perithecium - ✔✔flask-shaped ascocarp
✔✔Pycnidium - ✔✔An asexual hollow fruiting body lined inside with conidiophores.
✔✔Sclerotium - ✔✔Modified fungal hyphae that form a compact and hard vegetative
resting structure with a thick pigmented outer rind.
, ✔✔Spore - ✔✔A reproductive cell of fungi with a hard, protective coating
✔✔teliospore - ✔✔a spore found in rusts and smuts, produced in a telium; functions as
a resting spore, and then undergoes nuclear fusion, found in basidiomycetes
✔✔Zoospore - ✔✔Asexual spores of Oomycetes with flagella that can swim
✔✔Characteristics of Fungi - ✔✔Eukaryotic, have sexual and/or asexual reproduction,
do NOT photosynthesize, have resistant survival stages, have a vegetative mycelium
state, propagules are spores, need free moisture and high humidity for infection
✔✔How are fungi isolated and identified? - ✔✔Grown on pure culture media and
identified by their fruiting bodies and spores
✔✔Plasmodiophora brassicae - ✔✔Clubroot
✔✔Clubroot class - ✔✔Plasmodiophoromycetes
✔✔Clubroot life cycle - ✔✔Sexual structure: oospores from antheridium
Asexual structure: Zoospores from sporangium
Survival structure: Oospores
Host range: Most common brassica crops
✔✔Clubroot symptoms and signs - ✔✔Stunted and wilted plants, galls on roots,
Oospores can be observed
✔✔Clubroot Management - ✔✔Destroy infected roots, soil pH 7.2 or higher inhibits
spore germination, rotate crops, genetic resistance
✔✔Rhizopus sp. - ✔✔Soft rot
✔✔Soft rot class - ✔✔Zygomycetes
✔✔Clubroot biology - ✔✔Obligate parasite
✔✔Soft rot biology - ✔✔Saprophyte
✔✔Soft rot life cycle - ✔✔Sexual structure: zygospores from compatible hyphae
Asexual structure: sporangiospores from sporangium
Resistant survival stage: mycelium or spores on organic matter
Host range: Broad, notably strawberries, sugarbeet, peach, nectarine
QUESTIONS AND ANSWERS RATED A+
✔✔Why are monocyclic diseases less likely to result in serious epidemics? -
✔✔Controlling primary inoculum is much easier than controlling primary and secondary
inoculum. Once primary inoculum is controlled and dissemination is controlled, the
disease essentially stops developing.
✔✔How do sanitation practices impact monocyclic diseases? - ✔✔Epidemic may be
delayed, but severe epidemic can still occur if environmental conditions are favorable
for disease development
✔✔How do sanitation practices impact polycyclic diseases? - ✔✔Reducing primary
inoculum may reduce the amount of secondary inoculum produced. If rate of infection is
high, there is little effect. But if rate of infection is low, it may reduce an epidemic
✔✔Formae specialis - ✔✔Indicates a fungus is adapted to a specific host
✔✔Incubation period - ✔✔interval between initial infection and first signs and symptoms
✔✔Infection - ✔✔Invasion of a plant by a pathogen
✔✔Infestation - ✔✔Large numbers of pathogen present causing damage
✔✔Inoculum - ✔✔Infecting agent of a pathogen
✔✔Latent infection - ✔✔infection in which the infectious agent is present but not
causing symptoms
✔✔Mummy - ✔✔Dead, shriveled fruit that a pathogen may overwinter in
✔✔Overwintering - ✔✔the process by which some organisms pass through or wait out
the winter season
✔✔Pathovar - ✔✔subdivision of a plant pathogenic bacterial species defined by host
range
✔✔Propagule - ✔✔Portion of a plant which is used to generate a new plant
✔✔Race - ✔✔Strain of a virus adapted to a specific host
✔✔Soil inhabitant/soil resident - ✔✔Pathogen that can survive in the soil for long
periods of time
,✔✔Soil transient/soil invader - ✔✔Pathogen that can survive in the soil for a short
period of time
✔✔Vector - ✔✔An organism that can transport and transmit a disease
✔✔Apothecium - ✔✔cup-shaped ascocarp
✔✔Ascocarp - ✔✔Fruiting body of an ascomycete
✔✔Ascospore - ✔✔sexual spores of ascomycete fungi that develop within an ascus
✔✔Basidiospore - ✔✔A sexual fungal spore produced in a basidium, characteristic of
the basidiomycetes
✔✔Chlamydospore - ✔✔a thick-walled, asexual, resistant spore; a survival spore
✔✔Cleistothecium - ✔✔Closed ascocarp, typical of powdery mildews, also known as
the Chasmothecium
✔✔Conidium - ✔✔an asexually produced fungal spore formed on a conidiophore,
produced in ascomycetes
✔✔Fungi Imperfecti - ✔✔large and heterogeneous form division of fungi comprising
forms for which no sexually reproductive stage is known, also known as
Deuteromycetes
✔✔Fungus - ✔✔Saprophytic and parasitic spore-producing eukaryotic organisms that
lack chlorophyll and include molds, rusts, mildews, smuts, mushrooms, and yeasts.
✔✔Haustorium (Haustoria) - ✔✔specialized hypha of parasitic fungi that grows into a
host's tissues and absorbs its nutrients
✔✔Hypha - ✔✔one of many long, slender filaments that makes up the body of a fungus
✔✔Mycelium - ✔✔densely branched network of the hyphae of a fungus
✔✔Oospore - ✔✔thick-walled, sexually derived resting spore of oomycetes
✔✔Perithecium - ✔✔flask-shaped ascocarp
✔✔Pycnidium - ✔✔An asexual hollow fruiting body lined inside with conidiophores.
✔✔Sclerotium - ✔✔Modified fungal hyphae that form a compact and hard vegetative
resting structure with a thick pigmented outer rind.
, ✔✔Spore - ✔✔A reproductive cell of fungi with a hard, protective coating
✔✔teliospore - ✔✔a spore found in rusts and smuts, produced in a telium; functions as
a resting spore, and then undergoes nuclear fusion, found in basidiomycetes
✔✔Zoospore - ✔✔Asexual spores of Oomycetes with flagella that can swim
✔✔Characteristics of Fungi - ✔✔Eukaryotic, have sexual and/or asexual reproduction,
do NOT photosynthesize, have resistant survival stages, have a vegetative mycelium
state, propagules are spores, need free moisture and high humidity for infection
✔✔How are fungi isolated and identified? - ✔✔Grown on pure culture media and
identified by their fruiting bodies and spores
✔✔Plasmodiophora brassicae - ✔✔Clubroot
✔✔Clubroot class - ✔✔Plasmodiophoromycetes
✔✔Clubroot life cycle - ✔✔Sexual structure: oospores from antheridium
Asexual structure: Zoospores from sporangium
Survival structure: Oospores
Host range: Most common brassica crops
✔✔Clubroot symptoms and signs - ✔✔Stunted and wilted plants, galls on roots,
Oospores can be observed
✔✔Clubroot Management - ✔✔Destroy infected roots, soil pH 7.2 or higher inhibits
spore germination, rotate crops, genetic resistance
✔✔Rhizopus sp. - ✔✔Soft rot
✔✔Soft rot class - ✔✔Zygomycetes
✔✔Clubroot biology - ✔✔Obligate parasite
✔✔Soft rot biology - ✔✔Saprophyte
✔✔Soft rot life cycle - ✔✔Sexual structure: zygospores from compatible hyphae
Asexual structure: sporangiospores from sporangium
Resistant survival stage: mycelium or spores on organic matter
Host range: Broad, notably strawberries, sugarbeet, peach, nectarine
