HPD Flashcards
What is grey rot?
Grey rot, caused by the fungus Botrytis cinerea, can significantly damage fruit, leading to loss of yield and quality in wine.
How does grey rot affect grapes?
Grapes are vulnerable to grey rot if there are points of entry, such as rubbing against each other or being punctured by birds/insects.
What happens if flowers are affected by grey rot?
If flowers are affected, the fungus can remain dormant in the grape and re-emerge after véraison.
Which grape varieties are most at risk for grey rot?
Varieties with tight bunches or thin skins, such as Semilion, Sauvignon Blanc, and Pinot Noir, are most at risk.
When do grey rot spores become active?
Spores typically become active in periods of rainfall and high humidity.
What are management options for grey rot?
Management options include selecting resistant grape varieties, keeping an open canopy, and applying fungicides at key points in the season.
What is Eutypa dieback?
Eutypa dieback, also called Dead arm, is a fungal trunk disease that leads to rotten wood in vines and can affect entire vineyards.
What are the effects of Eutypa dieback on vineyards?
Eutypa dieback reduces yields significantly and can kill vines over a ten-year period if not managed.
How is Eutypa dieback spread?
Spores are spread by wind and infection occurs through pruning wounds, especially during rain.
What symptoms indicate Eutypa dieback in vines?
Symptoms include stunted shoot growth and yellow leaves in affected vines.
Which grape varieties are particularly susceptible to Eutypa dieback?
Grenache, Cabernet Sauvignon, and Sauvignon Blanc are particularly susceptible.
What are management options for Eutypa dieback?
Management options include pruning late, applying fungicide to pruning wounds, and cutting back affected trunks.
What is Phomopsis?
Phomopsis is a fungal disease that causes a reduction in yield.
When is Phomopsis particularly prevalent?
It is particularly prevalent in years with cool and wet springs followed by humidity and moderate temperatures.
What happens to infected canes?
Infected canes whiten and break off easily.
What symptoms do shoots from infected canes exhibit?
Shoots growing from these canes develop brown cracks at their bases.
How does Phomopsis affect leaves?
Leaves are also affected.
Which grape variety is very susceptible to Phomopsis?
Grenache is very susceptible.
Which grape variety is less prone to Phomopsis?
Cabernet Sauvignon is less prone to it.
What is the recommended timing for fungicide application?
Fungicides should be applied three weeks after budburst and then every two weeks if wet conditions continue.
What should be done with diseased and dead wood?
Diseased and dead wood should be removed during pruning and then burnt or buried.
What management technique may reduce the risk of Phomopsis?
Canopy management techniques that improve air flow within the canopy may also reduce risk of the disease.
What is Esca?
A complex fungal disease caused by a group of organisms prevalent in warmer and drier climates
Particularly affects regions like southern Europe and California
How does Esca typically enter the vine?
Through pruning wounds
What are the symptoms of Esca?
Tiger-striping of leaves and spotting inside the wood
What impact does Esca have on grapevines?
Reduces yield and leads to death within a few years
What is the primary management option for Esca?
Prevention of the disease
List some management practices for preventing Esca.
- Sourcing disease-free stock
- Trying new pruning techniques
- Not pruning in the rain
- Removing prunings promptly
- Disinfecting pruning wounds
What biological agent is being researched for Esca management?
Bacillus subtilis
What are other fungal diseases mentioned alongside Esca?
- Black rot
- Black-foot disease
- Bot canker
- Anthracnose
What is Pierce’s Disease?
A bacterial disease that quickly kills vines
Where did Pierce’s Disease originate?
On the American continent
What regions were initially affected by Pierce’s Disease?
Southern USA and Central America
What is the role of the bacterium in Pierce’s Disease?
Lives in sap channels of vines, clogging them and leading to vine death
What symptoms are associated with Pierce’s Disease?
Grape shriveling, dropping leaves, and vine death within one to five years
How is Pierce’s Disease spread?
By the sharpshooter insect acting as a vector
What insect is primarily responsible for spreading Pierce’s Disease?
Glassy-winged sharpshooter
Which grape varieties are more vulnerable to Pierce’s Disease?
- Chardonnay
- Pinot Noir
What are some management options for Pierce’s Disease?
- Reducing the number of vectors
- Using chemical insecticides
- Introducing wasps that feed on sharpshooter eggs
- Strict quarantine rules for plant movement
What future work is being done regarding Pierce’s Disease?
Developing Pierce’s Disease-resistant vines
