Final Flashcards
Coenocytic-
another name for a nonseptate hyphae.
Incubation period-
Time period from infection to appearance of symptoms
Necrotroph-
an organism that can live on living or dead hosts
Mycelium-
a tangled mass of hyphae
Latent period-
time from infection to production of secondary inoculum
Teleomorph-
term for the sexual or perfect stage of a fungus
Dikaryotic-
having two haploid cells
Inoculation-
transfer of inoculum onto the host plant
Necrosis-
death of plant tissue
anamorph-
term for the asexual or imperfect stage of a fungus
infection court-
initial site of contact between pathogen and surface of host plant
Hypotrophy-
reduction in cell size
Infection-
establishment of a pathogen within host; pathogen begins using nutrients from host.
Hyperplasia-
increase in cell number
Biotroph-
an organism that can grow and reproduce only on living hosts(obligate parasite)
List 3 ways that inoculum can be dispersed:
wind ,water, vectors
Symptom-
a physical responce of a plant to disease.
Sign-
when the physical pathogen is visible on its host
Infectious disease-
a disease that can be transmited to a healthy plant
Plant pathology-
the study of plant disease
Pathogen-
Biotic or abiotic factor that harms a plant or organism.
Biotroph-
an organism that can grow and reproduce only on living hosts(obligate parasite)
does not kill cells in advance, gets nutrients from living cells, are well adapted to one or a few related species. can invade plants at any stage.
3 factors of the disease triangle and a method of control for each-
Pathogen- chemical or cultural practices
Host- use resistant cultivars
Environment-Plant in areas where diseases are not located.
4 steps of Kochs Postulates for proof of pathogenicity-
- Pathogen must be consistent.
- Must be isolated and noted
- Must be able to infect a healthy plant w/ pathogen
- Must be able to isolate pathogen from infected plant.
Name 3 environmental factors that affect disease-
Temperature- some pathogens need warmer temps.
Water-some pathogens do well in humid or wet
Soil pH- some pathogens cannot survive in acidic soils.
5 MAJOR groups of plant pathogens
- Fungus
- Bacteria
- Viruses
- Nematodes
- Parasitic plants
Plasmogamy-
fusion of cells, which brings two sexually compatible nuclei into one cell. No fusion of nuclei
A diseased caused by environmental factors-
Abiotic
An organism that is usually parasitic but can become saprophytic-
Facultative Saprophyte
What is the term for a dense compacted aggregate of mycelium that is very resistant to unfavorable conditions-
Sclerotium
Indirect penetration-
when a pathogen enters through natural openings
Vector-
an organism capable of transmitting a pathogen
Fungi that form a symbiotic relationship by helping roots absorb nutrients:
mycorrhizae
Corn smut is an example of?
replacement of host tissue
Eradication-
removal of pathogens from infested soil and tools or from infected seeds or propagative parts.
What is the normal chromosome content of the vegetative phase of most fungi?
haploid
Rod shaped bacteria
Bacilliform
Meloidogyne spp.
Root knot nematodes
Basidiomycete fungi that are facultative saprophytes
Smuts
Plasmodium
a mass of cytoplasm containing many nucei but no cell wall
Virion
Individual virus particle
Bacteria that are round or spherical shaped-
coccal
Syncytium-
A nematode feeding site within a plant formed by the dissolution of cell walls.
heterodera spp.
Cyst nematodes
Caspid
protein coat that surrounds a virus particle, made up of protein.
Rusts-
Basidomycete fungi that are obligate parasites.
Giant cell-
a nematode feeding site within a plant created where the plant cell nucleus divides but cell division does not occur.
Name 3 genera of bacteria that cause plant diease
Erwinna
Xyella
Clavibacter
Most plant pathogenic bacteria are_____
gram-negative
Cryptobiosis-
how some nematodes go into dormancy
Basidiomycete fungi are_____ most of their life cycle?
hapliod
What is the difference between nonpersistent transmisson and persistent transmission?
Nonpersistant can be transmitted in seconds where in persistent the virus can take longer as well as multiply and infect its host insect.
How are prokaryotic cells different from eukaryotic cells?
Prokaryotic cells are single celled organisms w/o membrane bound organelles. Eukaryotic cells are multicellular and have membrane bound organelles.
2 diseases caused by Ascomycetes:
Sudden death syndrome in soybeans
Dollar spot in turf
2 diseases caused by Oomycetes:
Pythium root rot
Phytophtora root rot
3 ways bacteria are dispersed?
Water animals and insects
what are 2 signs of bacteria in plants?
Bacterial ooze,
bacterial steaming
4 categories of disease management in fungi?
Avoidance- dont plant in affected area
Exclusion-quarantine
Eradication-crop rotation
Protection-Fungicide
What type of fungi have clamp connections?
Basidiomycetes
What group is not apart of the fungi kingdom?
Oomycetes
How do viroids differ from viruses?
viruses have protein coats and viroids dont
What causes a mosaic symptoms
Virus
Migratory endoparasite-
a nematode that moves withing a plant while feeding on the plant
Bacteria that can only be cultured on complex specialized media:
Fastidious
A virus particle that has 20 sides and appears to be spherical:
Icosahedral
Phytoplasmas-
bacteria without cell walls that are pleomorphic, or variably shaped.
Galls at the base of the stem are caused by
Bacteria
what % of nematodes are plant parasites
10%
What is ELISA used for?
To identify viruses
galls on roots are caused by?
nematodes
Zoospores-
motile spores with flagella that are produced by some fungal and fungus like groups.
Is a virus alive?
No they require a host cell to reproduce. They cannot reproduce without a host and the energy of the host.
What is the genus name for the sunn hemp mosaic virus?
Tobamovirus
color difference between common rust and southern rust?
common-red
southern-orange to light brown
one effect of anthracnose stalk rot in corn?
Lodging
What phylum(fungus group)do smut fungus belong to?
Basidomycotta
SDS was first discovered in?
arkansas
Dollar spot grows activly while temperatures exceed 90F(t/F)
false
What stage of root knot nematode is motile?
J2 stage
What is the only sign of soybean cyst nematode?
the nematodes are visible in the roots.
What are two hosts in which the stewarts wilt pathogen can survive?
corn and corn flea beetle