bacterial and viral diseases Flashcards
one sign of bacterial disease of cereals?
bacterial blight- bacterial ooze
disease that is spread by six spotted leaf hoppers?
aster yellows
3 methods of transmission of viral diseases in cereal crops and give one example of the disease for each?
vectors- aphids- yellow dwarf
Rub- inoculation of infected plant- leaves- necrotic mottle
mites- yellow dwarf
Don’t spread spring wheat or barley near infected inter wheat
how does phytoplasm differ from bacteria and virus?
give one difference for each comparison.
Difference is that viruses rely on a host and have a protein capsule. Bacteria doesn’t.
phytoplasm doesn’t contain cell wall
bacteria contains a cell wall and cell membrane
Disease caused by bacteria and phytoplasmas in barley
aster yellows
bacterial blight
Disease caused by viruses in barley
barley stripe mosaic
yellow dwarf
Symptoms of aster yellows
blotched on older leaves and later the entire leaf
distorted awn
dwarf bushy plants
**no control measures
Symptoms of bacterial blight
pale green leaf sport or streaks which then enlarge to form translucent stripes
affected areas turn yellow and later light brown
bacterial ooze can occur
Aster yellow scientific name
macro steles fascifrons
bacterial blight scientific name
Xanthomonas translucens
barley stripe mosaic
seed borne virus
yellow blotches or streaks on leaves
later turn in to sea brown tissue
plants may be stunted
Do viruses or bacteria have scientific name
Viruses dont bacteria does
Yellow dwarf in barley is ….
Hosts?
the most important virus for cereal crops in the whole world
barley, wheat, rye, corn, brass families
Yellow dwarf in barley symptoms
yellow near tips of leaves then towards base
results in stunted plants, less tillers, sterile seeds
Diseases that are caused by bacteria in Corn
holcus
bacterial leaf blight
Diseases caused by viruses in corn
maize dwarf mosaic
Holcus spot scientific name
pseudomonas syingae
holcus symptoms in corn
leaf spot begins as dark green lesions and progressive into round oval shaped brown to white spots
relish brown margins surrounded by yellow halo
Bacterial leaf blight scientific name
Erwinia stewartia
bacterial leaf blight symptoms in corn
long pale green to tan streaks on leaves that turn brown stalk decays wilting of plant early infection causes stunted plants vector is flea beetle
Maize dwarf mosaic symptoms
mosaic or mottled dark green spots
develop into yellow veins
later streaks turn red
stunted plant with poor seed set
diseases caused by bacteria in oats
aster yellow
bacterial blight / halo blight
diseases caused by viruses in oats
necrotic mottle yellow dwarf (red leaf)
Bacterial blight in oats symptoms
light green oval spots with water soaked centres
heavily infected leaves turn brown and die
