Grape/Vine diseases Flashcards
What’s powdery meldew, where does it come from, what’s the trigger, what’s affected are what are the consequences?
- fungual disease
- native to North America
- affects all green parts of the plant > dusty white mildew growth
- consequences: inhibits bunch development and ripening
> prior to flowering: yields reduced
> after fruit set: berries struggle to reach veraison/ to get ripe
> if fruit affected: off-flavours
Consequences of powdery meldew?
Inhibits bunch development and ripening
> prior to flowering: yields reduced
> after fruit set: berries struggle to reach veraison/ to get ripe
> if fruit affected: off-flavours
Synonym of powdery meldew?
Oidium
or Oidium tuckerii
What’s affected by powdery meldew?
All green parts of the plant
Where does powdery meldew comes from and when was it first recorded in Europe?
North America
1847 in England
What’s the trigger for powdery meldew?
Uncinula necator fungus
What’s Oidium tuckerii?
The Uncinula necatorfungus for Oidium at it’s anamorph stage
How does powdery meldew looks like?
dusty white mildew growth on grapes leaves and shoots
How can powdery meldew can be controlled?
Sulfur, fungicides
What’s the synonym for Downy Meldew?
Peronospora
Where does powdery meldew comes from?
North America
What’s the agent of downy meldew?
Plasmopara viticola, fungual
When had powdery meldew spread to Europe?
Early 1880s
What’s affected by downy mildew?
The green parts of the plant
How can you recognise downy meldew?
Oil spot on the leaves
> spores germinate a white, cottony growth develops on the underside of the leaves
Downy meldew- what happens with the vine?
green portions of the vine
> leaves drop off the vine
> vine’s ability to photosynthesize is limited
What’s done to prevent against downy meldew?
Bordeaux Mixture, a spray of copper sulfate, water and lime
What happens with downy meldew after a winter?
fungus survives the winter on fallen leaves in the soil, and its spores reach the vine again
Synonym of Eutypa Dieback?
Dead arm
What causes the Eutypa Dieback disease and how is it caused?
Eutypa lata fungus
>Spores are carried by rain and enter the vine through pruning wounds
Where is Eutypa Dieback common?
In Mediterranean climates
What happens if a vine is infected by Eutypa lata fungus?
Infected vines experience stunted shoot growth as the fungus releases toxins, and eventually an infected cane may die—the dead arm
What’s are the consequences of Eutypa Dieback?
Yields drastic lower
Does not devalue the quality
Where does the well known wine “dead arm” comes from, who produces it and which variety is it
Dead Arm Shiraz> beneficial effect on grape quality
McLaren Vale, Australia
d’Arenberg
Which fungus manifests similar to the Eutypa lata fungus?
Phomopsis viticola fungus
Synonym for Esca?
Black Measles
Where does Esca thrives mostly?
Warmer climats
What practice is known to work against Esca?
no known control or cure.
What causes Esca?
complex of fungi, rather than a single organism
What’s the effect of Esca?
-On young vines: weaken growth, affect berry development and discolor leaves
> hot weather: an affected young vine may suddenly die
- In older vines: the disease affects the wood, causing the interior of the trunk and arms to soften and rot from the inside
How long live Esca- infected vines?
Rarely past 30 years
What aggravated Esca- problems?
-rainfall
-spread by wind
-spread by pruning sheares of careless vineyard workers
Where does Black Rot comes from?
North America
When spread Black Rot to Europe?
Late 1800s, with importation of phylloxera-resistant rootstocks
What causes Black Rot?
Guignardia bidwellifungus
How Black Rot originate?
black spot on the vine’s shoots, leaves, and berries
What are the consequences of Black Rot?
Yield reduction
How can Black Rot be controlled?
Fungicide sprays
What’s Bunch Rot?
grouping of similar diseases caused by a number of fungi species
What are the consequences of bunch rot?
reduce crop yields and may adversely affect the character of the wine, imbuing it with moldy off-flavors
What’s the most common forms of bunch rot?
Botrytis bunch rot > Botrytis cinerea
What’s the malevolent form of botrytis?
grey rot
What’s grey rot
Botrytis cinerea fungus break down the skin of berries and allow other yeasts and bacteria to rot the grapes.
What’s noble rot?
Botrytis fungus invades healthy white grapes under favorable conditions
What caused Pierce’s disease?
bacteriumXylella fastidiosa
> most commonly transmitted by the glassy-winged sharpshooter
Where’s sharpshooter mostly found?
near citrus orchards and oleander plants
What are the consequences of Pierce’s Disease?
rendering vines incapable of producing chlorophyll
> killing it within one to five years
Where’s the Pierce’s disease common?
southern United States and Mexico but is steadily moving northward in California
What cure or control is done against Pierce’s disease?
Neither cure nor a chemical control
> strict quarantines
What causes Crown Gall?
Agrobacterium tumefaciens
Synonym of Crown Gall?
Black Knot
What happens if a vine is Crown Gall affected?
vine develops tumors (galls) on its trunk, which girdle and essentially strangle the vine, withering or killing outright the portions of the vine above
When thrives Agrobacterium tumefaciens bacterium?
Colder climates
How does Crown Gall gets bader?
During winter freezes, when the vine’s trunk may be ruptured, the bacteria invade the outer trunk, rapidly multiplying and fomenting the onset of disease
What causes the Bacterial Blight?
Xanthomonas ampelinabacterium
What happens if a vine is affected by Bacterial Blight?
- often kills young grapevine shoots - shoots develop dark brown streaks in early spring, and eventually wither and die
What can be done to control Bacterial Blight?
hot water treatments and copper sprays, such as the Bordeaux Mixture.
How is Bacterial Blight spread?
by rain and compromised pruning tools
What causes Leafroll virus?
caused by a complex of at least nine different viruses
Which disease is the most responsible for the worldwide grape production losses?
Leafroll virus > 60% of the world’s grape production losses
What happens if a vine is affected by the Leafroll virus?
- multicolored leaves, combined with a characteristic downward curling of the leaves
- reduced yields
- delayed ripening.
How’s Leafroll virus spread?
propagation of infected vines or by an insect vector like the mealy bug
What can be done to cure Leafroll virus?
Currently nothing, but it won’t kill the vine
Only mealy bug control
What causes Fanleaf Degeneration?
nepovirus spread by soil nematodes feeding on infected roots
What happens if a vine is affected by Fanleaf Degeneration?
- leaves on an infected vine are malformed, resembling fans in appearance, and may form yellow bands around the veins
- deforms shoot growth
- leads to poor fruit set and shot (seedless) berries
- productive lifespan of the vine and its winter durability are diminished.
Where and when appeared Flavescence Dorée the first time?
1949
Armagnac
How spreads Lavescence Dorée disease?
- Leafhopper insects
- propagation of infected vines
What happens if a vine is affected by Flavescence Dorée?
- delay budbreak
- slow shoot growth
- eventually causing bunches to fall off the vine and berries to shrivel
- discolor leaves
- pustules and cracks to form
- may kill young vines.
Which kind of disease is Flavescence Dorée?
Phytoplasma Disease
What are the ingredients of a Bordeaux mixture?
Copper, sulfur, water, lime
