Viticulture Flashcards
What is the scientific name for powdery mildew?
Oidium (uncinula necator)
What is powdery mildew?
It infects all green parts of the plants and affects all green parts of the plants marking grapes leaves and shoots with dusty white mildew growth.
What can prevent powdery mildew?
Application of sulfur and other fungicides is used for control and prevention.
What happens if powdery mildew occurs prior to flowering?
Yields will be reduced.
What happens if powdery mildew affects the plants after fruit set?
The berries will struggle to achieve veraison and reach full size.
Name some fungal diseases.
Powdery Mildew Downy mildew Esca Eutypa Dieback Black Rot
How does powdery mildew occur?
The disk disease develops and spreads most rapidly in warm weather does well in dry weather and is a spread by dry winds. The spores develop in the winter time.
What is Downy mildew?
A spore called zoospore swims and needs moisture to germinate and infect and infection occurs when the downy spores move from the soil to the vine.
What type of conditions encourage the development of downy mildew?
Warm, humid springs and summers and is more prevalent with these conditions in Northern Europe
How can downy mildew affect the plant?
If severe, the leaves will drop off which then creates the loss of photosynthesis, causing delays in fruit ripening and levels of fruit sugar. Bud break and early shoot growth can be delayed the following Spring.
How is downy mildew contained?
Downy mildew is controlled organically with various preventative copper sprays, Phosphorous acid can also help.
What is esca?
Esca is a fungal disease that effects the wood of the vine and is more likely to affect old vines those at least 10 years old.
What is bunch rot?
AKA berry rot is caused by many species of yeasts and bacteria. Promoting good air circulation and sunlight exposure within the grapevine canopy reduces the risk. Pulling the leaves is also helpful.
What is Eutypa Dieback?
AKA Dying Arm or Dead Arm. A disease caused when spores shoot into the air during rain events and infect vines through the wood through fresh pruning wounds, working their way into the vines, choking off the sap and eventually killing the vine.
How is Eutypia Dieback diagnosed?
It can easily be diagnosed in the Spring: young shoots are stunted and yellow with small misshapen cupped leaves caused by toxins in the infected trunks and/or arms.
Removing the infected arms and trunks may help the vine.
What is black rot?
A disease caused by the fungus, Guignardia bidwelli which attacks young shoots, leaves, stems, and berries and spreads in only mild, wet weather.
It is controlled with fungicides sprayed from spring up to fruit ripening and removing the infected berries from the vineyard.
What is Daktulosphaira vitifoliae?
Phylloxera
How does Daktulosphaira vitifoliae affect the vine?
It feeds on the roots of the vine resulting in deformation and destroying the root system.
How are the vines protected from Daktulosphaira vitifoliae?
Vines are grafted onto American rootstock such as Vitus riparia to prevent phylloxera’s effect.
What major wine producing country is the one that is totally free from Phylloxera?
Chile
What are phytoplasmas?
Small and sometimes microscopic organisms similar to bacteria associated with diseases of the phleom (food-conducting tissue of the vine) transmitted by insects and grafting.
What are grapevine yellows?
A generic term for a group of related phytoplasma diseases of grape vines which poses a big threat to vines.
How are phytoplasma diseases introduced to the vine?
Pathogens similar to bacteria spread through an insect vector or rootstock grafting.
Generally speaking, which can be more devastating? Bacterial or viral disease?
Bacterial
How do viral diseases infectt the Vine?
Viral diseases spread through grafting or transmission by insects. There is no known cure for many common viral infections but they can be partially controlled by removal of appropriate sections of the Vine for propagation of new healthy vines.
Fungal diseases are manifested as what 2 things?
Mildew or mold
What climates are fungal diseases most prevalent in?
Warm and a damp climates are most conducive to these
What parts of the Vine do fungal diseases affect the most?
The root system or the canopy
What are the 4 categories of disease a Vine may be subject to?
Fungal
Bacterial
Viral
Phytoplasmic
Cordon de Royat and Geneva are examples of what kind of training?
Cordon training
With cordon de royat and Geneva training, which is most similar to Guyot? How is it different than Guyot?
Cordon de Royat but there’s a single spur pruned permanent cordon extending from the trunk rather than a 2 year old cane.
What is the trellising system that is widely used in Bordeaux (reds) and California (Napa Valley Cabs)?
Guyot
What is Guyot training?
Involves training a single, vertically grown cane to a horizontal position after the previous year’s harvest is complete. The other vertically grown canes are pruned.
Define single Guyot.
It has one cane and one spur and the length of the cane may be fixed by appellation laws.
Define Guyot Double.
Double Guyot is the most common vine training system in Bordeaux and has 2 canes and 2 spurs, the canes being trained from side to side.
Sometimes the canes are arched such as in the Jura.
What are Gobelet-pruned vines called in Spain?
En Vaso
What are Gobelet-pruned vines called in Italy?
Albarello
What are Gobelet-pruned vines called in Australia?
Bush
What is the Gobelet form of vine training?
The spurs are arranged on short arms in an approximate circle at the top of a short trunk. The vines are free standing and the system is best suited to low-vingour vineyards in drier climates. The trunk is short and foliage unsupported by wires.
Where is the Gobelet method more commonly found?
It is widespread in France, from Beaujolais and southward, also seen in Mediterranean countries like Italy, Spain, and Portugal as well as New World countries like Australia, South Africa, and California.
What are Gobelet-pruned vines called in Portugal?
En Taca
What are the 2 essential methods of pruning?
Spur-pruning
Cane-pruning
Describe cane pruning.
The pruner selects two or four shoots (canes) from the previous season and trains them all along the trellis wires. The other canes are removed and new shoots sprout from the buds on the selected canes in Spring.
Describe spur pruning.
Spur pruning is done on vines that retain 1 or 2 pairs of long canes (a permanent cordon) trained along a trellised a system. Each Winter, new canes that have grown along the permanent cordon are cut back to a small shoot containing 2 buds, known as a spur. In Spring new growth develops from the buds on the spur.
What head training method does Guyot use?
Cane-Pruning
What head training method does Gobelet use?
Spur-training
How are cordon-trained vines pruned?
Spur-pruned
What are the most common vine training techniques?
Head-training
Cordon training
What is a spur?
A spur is a cane cut back to two buds.
What are buds?
Point along the cane that produce a shoot in the spring.
What is a cane?
The product of a green shoot (fruiting cane) hardening to become a woody extension.
Vine training encompasses what 3 practices for the Vine?
Pruning, shaping, and trellising.
What is the objective for pruning, shaping, and trellising?
The objective is to maximize the vines performance in local conditions and to keep its canes from touching the ground and establishing new roots.
After how many years will the yield of the vine begin to decline?
After 20 years
How old does a Vine have to be for its root system to be considered mature?
Rip system will be mature for a Vine at 10 years of age.
In many European appellations newly planted Vine must not be used for production until it’s at least how many years old?
At least 3 years old
By what year is the grapevine considered mature? What stabilizes for the Vine at this time?
By the 6th year the grapevine is considered mature, chute growth and the vines annual yield stabilizes at maturity.
What is the most common rootstock which vinifera grapes are grafted on to protect the Vine from Phylloxera?
Vitis Riparia
What are 5 attributes commonly selected for clones.
Disease resistance Hardiness Yield Aromatics Structure Color
How can acidic soil, that with a low ph, be treated?
Applications of lime can reduce the effect of low ph.
What does high soil pH like that found in limestone rich soils encourage in the grapes?
Higher acidity in the grapes (lowers pH)
What does well drained soil is encourage in regards to Vine growth?
Encourages the Vine to dig deeply for water and minerals
When do Mediterranean climates receive most rainfall seasonally?
Winter and Spring
How much annual rainfall does a Vine required to produce an adequate crop?
20-30 inches annually
What is the California heat summation index? Sometimes known as the winkler scale.
Method for classifying climates solely by temperature.
How our degree days calculated for the California heat summation index?
They are calculated by multiplying the days in each month of the growing season by the mean of numbers of degrees over 50 Fahrenheit for that month. The months totals are then added up to come up with the number of degree days.
For temperature, what does the Vine prefer as a mean annual range in Fahrenheit?
A prefers a mean range of 50 to 68 Fahrenheit with an ideal temperature of 57ﾟF.
What summer temperature dude grapevines require on average to successfully ripen red grapes?
Red grapes require an average temperature of 70ﾟF.
What summer temperature do grapevines require on average to successfully ripe in white grapes?
White require an average temperature of 66ﾟF.
Which grapes are generally harvested 1st, red or white?
Whites are generally harvested first.
In addition to the grapes ripe main, what else ripens in tandem?
Cane ripening occurs in tandem with grape ripening.
Which grape is notorious for ripening unevenly?
Zinfandel
When does veraison typically occur in the northern hemisphere?
August
What happens during veraison?
Sugars are moved from the leaf system into the fruit and the grapes soften and change color.
What percentage of embryos achieve fruit set?
30%
When does flowering typically occur in relation to Bud break?
It occurs 6 to 13 weeks after the initial Bud break depending on the climate.
What 3 hazards in the Vine are most susceptible during Bud break?
Damaging effects of cold, frost, and wind.
During but break the Vine is most susceptible to what vineyard hazard?
Frost
By break occurs as the average temperature surpasses what temperature in Fahrenheit? When does this usually occur in the northern hemisphere
50ﾟF
Usually occurs in March or April
What are the 6 stages of a vines life cycle in order?
Budbreak Flowering Fruit Set Véraison Harvest Post-Harvest (pruning)
What decisions does the viticulturist confront?
Vine Training Pruning Methods Canopy Management Fertilization Irrigation Harvest Dates Disease Control Monitors development of vineyard in general
