WSET Advanced Chapter 3 Vineyard Management AKC3 Flashcards
(40 cards)
Site Selection (Three Factors)
Environmental: Use data to determine average temperature, rainfall and sunlight, soil fertility and drainage. Helps decide Varietal, Training, Plant Density and Trellising.
Vine Management - Why Is It Necessary?
Left alone, vines will produce grapes sweet enough to attract brids, but not ripe enough for winemaking, and focus more on plant growth than fruit ripening. Viticulturists use plant density, pruning and trellising to control ripeness and quality.
Trellis
A vine management system consisting of a permanent structure of stakes and wires.With no trellising, vines go unsupported.
Training
The vine’s permanent wood and canes are trained to follow the trellising system. It manages the direction and growth of the following years shoots. Shoot positioning affects the amount of sunlight that is intercepted by the leaves and exposure to sunlight, wind and rain of the shoots.
Pruning
The removal of unwanted leaves, canes and permanent wood, either during winter of the growing season.
Winter Pruning: Purposed and Two Types
Purpose: To determine the number and location of the buds, which will form shoots for the production of fruit in the coming harvest.
Summer Pruning
Trimming the canopy to restrict vegetative growth, direct sugar production to the grape, and can involve leaf stripping so the grapes are exposed to sunshine.
Bush Training System
A vertical stump of permanent wood is pruned to retain a number of spurs at the head of the vine. The shoots sprawl across the ground. Practical in hot, dry, sunny climates (Southern Rhone, Barossa Valley), not in cool areas because grapes are shaded and wouldn’t ripen. Not suitable for mechanical harvesting. Sometimes referred to as Gobelet
Vertical Shoot Positioning (VSP)
Most common training system in the world, and may be used with replacement-cane or cordon-spur pruning. Single canopy of shoots are trained upwards, tied to trellis, and may extend to both sides or trunk or only one, then trained horizontally. Low trained for heat retention, high trained to avoid frost. Keeps vines separate, aerated, exposed, good for high density planting.
Big Vines
Big vine training systems are planted to low densities and ensure that all light is utilized. Lots of permanent wood. Can use VSP with a vertically split canopy, others train shoots downwards or have multiple canopies. Usually spur pruned, can be mechanically harvested. Developed to restrict vine vigor in high-nutrient areas.
Measuring Vine Vigor
Vine vigor is measured by the number and size of shoots and leaves it grows in a season. This is driven by nutrients, water, sunlight, and heat. Planting density, cover crops, number of buds per vine and rootstocks all can manage vigor.
Managing Ripeness
Ripeness is achieved when a grape has the level of sugar nad physiological ripeness for the style of wine, far above what would occur in nature. Winter Pruning helps achieve this by defining number and location of buds. Cool sites need fewer buds, because it is hard to ripen many grapes.
Cordon
A horizontal extension of a wine trunk
Managing Yields
Yields are measured in terms of weight (Kg per hectare) or volume (Hectolitres per Hectare). Producers may have contractual or regulatory obligations to meet Yield requirements. Green harvesting limits yields.
Green Harvesting
Removing immature grapes shortly after Veraison. Risky, because the vine may compensate for the loss by increasing the size of the remaining grapes, diluting their flavors.
Veraison
The moment when a grape begins to change color.
Nematodes
Microscopic worms that attack vine roots and may transmit viruses. Root damage reduces yields and leaves the vines susceptible to infection, and water and nutrient stress. Treatment is hard, so prevention by soil sanitisation is recommended, as is planting nematode-resisting rootstock.
Birds and Mammals
They eat grapes, and cause damage that allows rot. Birds, deer, boar, etc. Netting, fencing and bird scares are solutions.
Insects and Arachnids
Caterpillars, moths, beetles, mites, aphids, etc, all feed on plant matter, damaging shoots and leaves, limiting photosynthesis, damaging ripening fruit, and even tainting wine flavor.
Downy Mildew
Thrives in warm, humid conditions. Attacks green parts of the vine, especially young leaves. Leaf damage impedes ripening, and damage to berries reduces yield.
Powdery Mildew
Likes warm, shady conditions and develops on green parts of the vine. It can affect bud development and shoot growth. Affects bud development and shoot growth, can cause grapes to split and gives wine a moldy, bitter taint.
Grey Rot
Likes damp and humid conditions. Can damage parts of the vine but causes the greatest problems by attacking immature berries. Taints flavor, reduces yields, and causes color loss in black fruit.
Controlling Mildew
Traditionally, treated by spraying with sulfur-based (downy) or copper-based (powdery) sprays, but now chemicals are often used. Spraying is done by tractor, helicopter, or airplane. All spraying must stop before the harvest. It can also be reduced by canopy management.
Noble Rot
Desired Gray Rot, caused by the fungus Botrytis Cinerea. It attacks when the grapes are ripe, encouraged by humid misty mornings and warm, sunny days. The fungus punctures the grape skin, allowing the water to evaporate. Acids and sugars are concentrated, and other flavors develop. These grapes go into the world’s best sweet wines.
