PCA PLANT PATHOGENS Exam 2 QUESTIONS AND ANSWERS
(VERIFIED AND WELL DETAILED ANSWERS) LATEST UPDATE 2025
What is the name of the pathogen that causes coffee rust? -CORREC ANSWER-
Hemileia vastatrix (fungus, obligate parasite)
What is the center of origin of hemileia vastatrix and its host plant? -CORREC
ANSWER- first observed in Kenya, plant=Ethiopia (East Africa)
How is coffee produced? -CORREC ANSWER- -cool nights, nutrient rich soil,
high rainfall
-3 years from planting to berry production
-coffee does not mature evenly (multiple harvest, labor intensive)
-blooms one time a year with white fragrant flowers
-produces berries covered with tough parchment (inside are two beans)
-flesh has to be removed with grinding and fermentation (gives flavor)
-seeds dry in sun (needs to be stirred regularly)
-coffee beans shipped with parchment on
-mechanically removed before roasting
How does coffee production worsen the development of coffee rust? -CORREC
ANSWER- -completes life cycle on coffee; only asexual stage occurs
,Disease cycle of coffee rust -CORREC ANSWER- sources of inoculum: the
fungus arrives in plantation as asexual urediniosporeson wind/land on leaves.
Under warm humid conditions germinate by hyphae
-hyphae penetrate the leaves via stomata and rapidly colonize host tissue
-fungus produces spores that infect bushes within miles of infected tree
-spores carried by wind, rain, insects, clothes, tools
-once tree is infected, it stays infected (new leaves attacked)
-berry/bean production declines and tree dies prematurely
"Urediniospores initiate infections that develop into lesions that produce more
urediniospores"
Coffee rust management -CORREC ANSWER- -establish at high altitudes
-plant coffee with good spacing with lots of sun
-low humidity
-easier to apply pesticides
-problem: the destruction of natural ecosystems
-pruning infected branches
-removing debris
-many effective chemicals
-use resistant cultivars (ex: canephora/robusta=not the best coffee)
-due to clearing of forests, many have been lost
Coffee origin and history part 1 -CORREC ANSWER- 800 A.D. -goat herder
Kaldi noticed goats getting jittery after eating berries in Ethiopia. He tried it
200 B.C Arabs conquered Ethiopia (searched for spices, stimulants - found coffee
and began trade
,1000 A.D Arabs brought coffee to Yemen (consumed by holy men)
1554- many coffee houses in Turkey
1615- Venice merchant introduced coffee to Europe
Arabs had a monopoly on coffee - coffee in Europe was expensive
Coffee origin and history part 2 -CORREC ANSWER- -Dutch get it and smuggle
plant into Amsterdam, then to Louis XIV
-Brought to Caribbean and central/south America
-GABRIEL MATHIEU DE CLIEU: raided bot. gardens and took clipping to
Martinique (very little genetic diversity)
1700's: coffee consumption ^
Dutch in 18th century -CORREC ANSWER- -thriving on coffee production
-1797: English seized Sri Lanka from Dutch
-1825: England started "coffee rush"
-very little was owned by Sri Lankans
Who were the Tamil people? -CORREC ANSWER- They were brought to Sri
Lanka from India as cheap labor
How many pounds of coffee were exported from Sri Lanka in 1870? -CORREC
ANSWER- 100 million pounds per year
What was the "coffee rush" -CORREC ANSWER- When England controlled the
market for coffee
British constructed railways for coffee transport
, Most valuable product in British Empire
Dr. H Thwaites (Superintendent of the Royal Botanical Gardens) -CORREC
ANSWER- -suggested it was bad for them to be reliant on on commodity
-recommended diversity
1867: coffee rust observed -CORREC ANSWER- -distributed and didn't get
much attention at first
-when coffee productivity declined, they cut down more trees to plant more coffee
bushes
-keeps getting worse
M.J. Berkeley and coffee rust -CORREC ANSWER- -noticed it was similar to
stem rust of wheat
-he named it hemileia vastatrix
1880 Harry Marshall Ward -CORREC ANSWER- -sent to Sri Lanka to study
coffee
-2 years later he documented coffee rust cycle
-showed rust spores are wind-borne
-recommended using lime sulfur BEFORE fungus arrived
-failed to save coffee industry
In 22 years... -CORREC ANSWER- -Sri Lanka went from the largest coffee
producer in the world to none
-economy ruined
(VERIFIED AND WELL DETAILED ANSWERS) LATEST UPDATE 2025
What is the name of the pathogen that causes coffee rust? -CORREC ANSWER-
Hemileia vastatrix (fungus, obligate parasite)
What is the center of origin of hemileia vastatrix and its host plant? -CORREC
ANSWER- first observed in Kenya, plant=Ethiopia (East Africa)
How is coffee produced? -CORREC ANSWER- -cool nights, nutrient rich soil,
high rainfall
-3 years from planting to berry production
-coffee does not mature evenly (multiple harvest, labor intensive)
-blooms one time a year with white fragrant flowers
-produces berries covered with tough parchment (inside are two beans)
-flesh has to be removed with grinding and fermentation (gives flavor)
-seeds dry in sun (needs to be stirred regularly)
-coffee beans shipped with parchment on
-mechanically removed before roasting
How does coffee production worsen the development of coffee rust? -CORREC
ANSWER- -completes life cycle on coffee; only asexual stage occurs
,Disease cycle of coffee rust -CORREC ANSWER- sources of inoculum: the
fungus arrives in plantation as asexual urediniosporeson wind/land on leaves.
Under warm humid conditions germinate by hyphae
-hyphae penetrate the leaves via stomata and rapidly colonize host tissue
-fungus produces spores that infect bushes within miles of infected tree
-spores carried by wind, rain, insects, clothes, tools
-once tree is infected, it stays infected (new leaves attacked)
-berry/bean production declines and tree dies prematurely
"Urediniospores initiate infections that develop into lesions that produce more
urediniospores"
Coffee rust management -CORREC ANSWER- -establish at high altitudes
-plant coffee with good spacing with lots of sun
-low humidity
-easier to apply pesticides
-problem: the destruction of natural ecosystems
-pruning infected branches
-removing debris
-many effective chemicals
-use resistant cultivars (ex: canephora/robusta=not the best coffee)
-due to clearing of forests, many have been lost
Coffee origin and history part 1 -CORREC ANSWER- 800 A.D. -goat herder
Kaldi noticed goats getting jittery after eating berries in Ethiopia. He tried it
200 B.C Arabs conquered Ethiopia (searched for spices, stimulants - found coffee
and began trade
,1000 A.D Arabs brought coffee to Yemen (consumed by holy men)
1554- many coffee houses in Turkey
1615- Venice merchant introduced coffee to Europe
Arabs had a monopoly on coffee - coffee in Europe was expensive
Coffee origin and history part 2 -CORREC ANSWER- -Dutch get it and smuggle
plant into Amsterdam, then to Louis XIV
-Brought to Caribbean and central/south America
-GABRIEL MATHIEU DE CLIEU: raided bot. gardens and took clipping to
Martinique (very little genetic diversity)
1700's: coffee consumption ^
Dutch in 18th century -CORREC ANSWER- -thriving on coffee production
-1797: English seized Sri Lanka from Dutch
-1825: England started "coffee rush"
-very little was owned by Sri Lankans
Who were the Tamil people? -CORREC ANSWER- They were brought to Sri
Lanka from India as cheap labor
How many pounds of coffee were exported from Sri Lanka in 1870? -CORREC
ANSWER- 100 million pounds per year
What was the "coffee rush" -CORREC ANSWER- When England controlled the
market for coffee
British constructed railways for coffee transport
, Most valuable product in British Empire
Dr. H Thwaites (Superintendent of the Royal Botanical Gardens) -CORREC
ANSWER- -suggested it was bad for them to be reliant on on commodity
-recommended diversity
1867: coffee rust observed -CORREC ANSWER- -distributed and didn't get
much attention at first
-when coffee productivity declined, they cut down more trees to plant more coffee
bushes
-keeps getting worse
M.J. Berkeley and coffee rust -CORREC ANSWER- -noticed it was similar to
stem rust of wheat
-he named it hemileia vastatrix
1880 Harry Marshall Ward -CORREC ANSWER- -sent to Sri Lanka to study
coffee
-2 years later he documented coffee rust cycle
-showed rust spores are wind-borne
-recommended using lime sulfur BEFORE fungus arrived
-failed to save coffee industry
In 22 years... -CORREC ANSWER- -Sri Lanka went from the largest coffee
producer in the world to none
-economy ruined
