Fundamentals: Viticulture Flashcards
What happens in the vineyard from month to month.
- December-March: Pruning
- March: Bud Break
- May: Flowering
- July: Leaf-pulling, Summer Pruning, Green Harvest
- August: Veraison/Ripening
- August-September-October: Harvest
- October: Fertilize, Hill Up
- November: Leaf Fall, Trellis Adjustments
What is the purpose of winter pruning?
- Maintain a specific size & shape
- Focus vigor, thus controlling productivity
Describe what is done for winter pruning.
Clippings are removed from the vineyard rows and mechanically ground or burned. Chips and ash are returned to the vineyard and deposited between the rows.
What happends during Bud Break?
- The buds swell and open. For 3-4 weeks after, there is a period of shoot growth which is accelerated by warmth and retarded by cold.
- Earth, which may have been hilled up around the base of the grapevines in the fall to protect the trunk and graft union from winter freezes, is removed.
What is inflorescence?
This is the flowering that occurs 6-9 weeks after bud break.
The bloom typically lasts 8-10 days.
What occurs after flowering?
After the grapes self-pollinate, there is berry set, which marks the transition of fertilized flower to grape.
They are initially small, green and hard, high in acid and low in sugar.
How long after flowering/berry set are early-ripening varieties picked?
8-10 weeks
How long after flowering/berry set are late-ripening varieties picked?
18 weeks
What is the purpose of leaf-pulling?
- Exposes clusters to the sun
- Increases air movement within the canopy (mitigating humidity & disease pressure)
What is the purpose of summer pruning?
Shoots may be tipped to slow down vegetative growth.
What is the purpose of green harvest?
To limit yield.
What happens during veraison?
- Vegetative grown stops
- the vine puts energy toward ripening its fruit
- Green grapes become translucent
- Pigmented grapes change colour
- Berries soften
- sugars increase
- acids decrease
What influences the length of time between veraison and harvest?
- Grape variety
- Intended wine style
- Number of sunlight hours received
- Heat
- Growing conditions
As a general rule, most grapes are picked how many days after veraison?
45
What is the range for the growing season of the grapevine?
165-180 days
What happens at the end of the growing season?
- Vineyard fertilization
- hilling up the vines
What happens in the vineyard after leaf fall?
Vignerons prepare for winter pruning by removing fasteners & lowering catch wires where present.
What are some general threats to the grapevine?
- Fungi
- Viruses
- Phytoplasmas
- Bacteria
- Insects
- Animals
What are the 3 most catastrophic and long-lasting afflictions of vines in France?
- Phylloxera
- Downy mildew
- Powdery mildew
These are all native to North America and appeared in Europe with the advent of streamships and their speedy Atlantic crossing that enable these organisms to surviv the voyage and wreak havoc once offloaded on shore.
How does phylloxera kill the grapevine?
This small insect kills the grapevine by attacking its roots. With each bite, it injects saliva. This creates galls or knots of uncontrolled cell growth.
European vines (Vitis vinifera) do not have the ability to heal over the bite wounds, resulting in bacteria and fungi entering the plant and rot the root, causting further damage.
What solution was discovered to protect European grapevines from phylloxera?
Grafting European grapevine scions onto American rootstock. North American vines are largely immune to this vineyard pest.
Developed by Jura-born French botanist & mycologist Pierre-Marie-Alexis Millardet along with botanist Jules Emile Planchon.
What benefit did phylloxera bring to the vineyards of France?
- Before phylloxera, grapevines were propagated by “layering” (marcottage or provignage), in which different grape varieties were grown together in a haphazard vineyard plan.
- Vignerons used the crisis to replant in rows. The farm tractor had just been invented and mechanization required order.
- Grapevines of earch variety were previously harvest and fermented together, so growers were picking under-ripe, perfectly-ripe and over-ripe grapes. The replanting helped to better manage maturity and ripeness at harvest.
- Many vignerons opted to plant better clones or different varieties, while others were forced to do so
What is another name for powdery mildew?
Oidium
What is powdery mildew?
A fungal disease that blankets the vine with thick, white filaments.
If an outbreak occurs before flowering, yields are reduced.
If the grape clusters become infected, they will not achieve full pigment development or grow to max. size. The fruit will be marked by off-flavours.
What is used to combat powdery mildew?
Sulphur sprays
What is another name for downy mildew?
Peronospera
What is downy mildew?
A fungal disease that germinates in warm, humid weather. It attacks the leaves and stems, first with what appear to be “oil spots,” then with white cotton filaments. An outbreak causes the vines to lose their leaves, which can delay ripening or prevent ripening altogether.
What is used to combat downy mildew?
“Bordeaux Mixture” or copper-sulfate application
Developed by Jura-born French botanist & mycologist Pierre-Marie-Alexis Millarder.
What pest has become a more recent threat to the vineyards in Europe?
The Asian fruit fly (Drosophila suzukii)
The females lay eggs inside soft fruits like grapes and their larvae hatch and feed on the pulp. When the grape skins are compromised, acetic acid bacteria and fungi enter the berry. Up to 13 generations can hatch in a single year, making an infestation particularly devastating.
What is used to combat the Asian fruit fly?
Many have resorted to agrochemical control.
Effective bait and kill traps are now in development.
What fungus can be both beneficial and detrimental to the grapevine?
Botrytis cinerea
Positive or negative effects depend on the conditions in which the mold grows.
* Noble rot (Pourriture Noble): cool, moist nights & mornings need to be followed by warm, dry afternoons
* Gray rot: occurs when there is continuous wet weather in the weeks leading up to harvest
Describe what happens to grapes affected by noble rot.
This fungus affects tight-clustered, thin-skinned grape varieties. The mold penetrates the grape skin, desiccates the berry, and concentrates sugars and other flavour compounds.
* Total sugar content reduced by one-third.
* Tartaric acid is dropped by five/sixths.
* Malic acid is dropped by one/third.
* Water content reduced to half.
* Overall increase in total extract due to the diminishing proportion of liquid to solids.
* Gluconic acid is produced by the mold, which imparts a honeyed character to the wines made from botrytized fruit.
What is coulure?
This is poor fruit set caused by cloudy, cold and/or wet weather during the flowering phase.
A lack of carbohydrates within the vine itself causes the stems to shrivel and shed the nascent berries, decreasing crop loads.
Other causes:
* an over-vigorous vine on a too fertile site (excessive fertilizer): sugars are prioritized to vegetation instead of grape clusters
* an overly dense vine canopy: more leaves are shaded vs leaves exposed to the sun resulting in a carbohydrate shortfall
Which grape varieties are most vulnerable to coulure?
- Merlot
- Malbec
What are shoots?
New green growth on the grapevine.
What are canes?
Old shoots that have lignified (become woody).
What factors are considered for the positioning of the grapevine?
- Harvest method: Mechanisation of manual
- Vinetraining method
- Air circulation to prevent fungal diseases
- Leaf exposure to sunlight
- Climate/temperature: whether to expose grapes to sun or shade them
- Buds developing for next year’s crop (cluster primordia): require sunlight exposure for a healthy yield
- Grape variety
- Vineyard site & macroclimate
How is it that good years come in twos?
Because the buds on the current year’s shoots are developing the following year’s crop, a “good” year is often followed by another “good” year (if weather is not negatively impacted).
Bordeaux vintages are a prime example: Many good and/or great vintages come in pairs:
* 2000 & 20001
* 2005 & 2006
* 2009 & 2010
* 2015 & 2016
How is Grenache often trained and why?
Gobelet (without a support trellis)
This variety has fruitful basal buds (those closest to the trunk). Its canes are strong & upright and stay that way even in windy conditions.
The canes are trimmed to spurs (just 1-2 buds).
How is Syrah typically trained?
Guyot, a “long” (cane) pruning method with 6-10 buds.
This variety does not have fruitful basal buds and its canes are weak. In the Northern Rhone it is tied to stakes.
Name the training methods found in France.
Most typical:
* Guyot
* Gobelet
* Cordon
Regional methods:
* Eventail (Beaujolais, Savoie & Languedoc)
* Vallee de la Marne
* Chablis (predominantly used in Champagne for Chardonnay)
