D1 - Viticulture Flashcards
Types of buds
Prompt Buds and Compound Bud
What is the internode?
The distance between two leaves. It determines the quantity of buds in a given length of cane (long internode = small crop)
What does it mean that vines are Lianas?
They do not produce extensive supporting structures.
In the wild they climb trees
Their shoots experience rapid vertical growth to compete for sunlight
What are Prompt buds?
also called lateral buds.
They develop into lateral during the current growing season
They are typically non-fruiting but may produce small clusters known as second crop
Explain compound buds
They spend the year maturing and develop into shoots in future years.
Compound buds are the most fruitful
They normally have a primary, a secondary and a tertiary bud
Other names for compound buds
Dormant or latent
What are the petioles?
The joint between a shoot and a leaf stalk
It is where buds are formed
What is the bloom of the grape?
The powdery waxy coating that covers the outside of the grape’s skin
What is the function of lateral shoots?
Allow the plant to grown if the tips of the primary shoots have been damaged.
Benefits and drawbacks of lateral buds
The one located near the top end of the primary ones, can benefit from sunlight and provide extra source of photosynthates.
If located neat the fruiting zone - too much shading on the bunches.
Characteristics of the second crop
They form on lateral shoots
They are not the norm, some varieties have more tendency to developing them - PN
The grapes ripen later
They are often removed with green harvesting
What is somata?
They are pores on the downside of the leaves that allow the exchange of gas and water with the atmosphere to allow photosynthesis to happen
What are the ideal conditions for photosynthesis to be at its highest rates?
Temperature: 18 - 33 C
Sunlight: 1/3 + of Full sunshine
What is an inflorescence?
a cluster of flowers on a stem, which becomes a bunch of grapes at fruit set
What is flowering?
The process in which individual flowers open up and expose the pollen-bearing stamens
How does fertilisation happen?
The pollen grains are shed and land on the moistened stigma surface, (pollination)
Here, they germinate, with each pollen grain producing a pollen tube. These pollen tubes penetrate the stigma and then the ovule in the ovary.
Where are flower clusters located?
at a node, opposite to a leaf
opposite to the first 1 or 2 leaves there will usually be no flower cluster. They will appear in the next 1-3 leaves, and will reduce in size as they move away from old wood.
Flowering cylce
Flowering process extends for two consecutive growing seasons. It is first induced in compound buds during summer, but initiation and floral development occurs in the following spring.
What are gubberellins?
Hormones that promotes shoot elongation, and therefore, delay of floral induction.
What are Cytokinins?
hormones produced by the root tips that promote bud break
What is the xylem ?
Part of the plant’s conduction system that transports water and solutes from the roots to the shoots
What is the phloem?
Part of the circulation system that conducts photosynthates and nutrients from the leaves to the rest of the plant. After véraison, all the water that the berries receive is transported through the Phloem.
Parts of the circulation system of the plant
Xylem and Phloem
What does it mean that the commercial vines are hermaphrodite?
That they are self-pollinating, their flowers are dotted with the male and female organs (pollen and ovary). They also do not depend on wind or insects to be pollinated, as the distance between the pollen stamens and the stigma is extremely small.
What are the factors that influence the root system size?
Type of rootstock, soil conditions and water supply
Factors that restrict root growth
- Shallow soils, especially those overlying an impervious rock or compacted soil
- water logged
- imbalanced soils
Functions of the roots
- anchor the plant in the soil
- conduct nutrients and moisture
- store reserves (CH)
- produce hormones
Consequences of a cold and wet spring
the root-hairs cant grow, leading to little hormone and sap production. Budburst is delayed, the ripening season will be shorter and the grape ripening may end in bad weather conditions.
what happens to the vine during dormancy?
- leaves fall
- green canes lignify
- buds seal against winter
- migration of CH ceases
Needs of the vine and adverse conditions during dormancy
- Needs: temperatures under 10°C
- Adverse conditions: Extremely low temperatures or unusual mild temperatures
What is Bud-burst?
The process in which buds swell and open. new shoots will then start to emerge.
vine’s needs and adverse conditions during bud-burst
- Needs: av. temperature in air and soil above 10°C, stored CH, sunlight, nutrients and water
- adverse conditions: Frost, cold soils, water stress, low CH levels
What temperature is required to the onset of bud break?
- Normally around 10°C
- this depends on the variety: early-budding ones will break at lower temperatures, while late-budding ones require higher temperatures.
What is bud-rubbing?
taking out buds at the beginning of the growing season. This is carried out where there is usually an excess of shoots, or where yields are restricted
What are the benefits of bud/shoot-rubbing?
- remaining shoots will grow in more open conditions
- reduction of shading
- higher light interception will increase bud fruitfulness in the following growing season
- reduction of fungal disease incidence
When is bud-rubbing normally practised?
in high-quality cordon-trained, spur-pruned vineyards and where there is usually an excess of shoots
When does shoot and leaf growth take place at its highest rate?
between budburst and flowering
How does CH reserves affect bud-burst?
- CH stores will sustain initial growth
- If CH levels are low, initial growth will be delayed and stunted.
Why may the CH reserve levels be too low at the beginning of the growing season?
It may be caused by excessive leaf removal or excessive high yields during the previous growing season.
ways of controlling weed on the vineyard floor
- cultivating using harrows
- grassed down and mown
- use herbicides
- Animal Grazing
- Plant cover crops
- mulching
- Synthetic Strips
When does flowering normally take place?
Within 8 week from budburst
Vine’s needs and adverse conditions during flowering
- Needs: Warm temperatures (+17°C), sunlight, water and nutrients
- adverse conditions: low temperatures, windy, cloudy or rainy conditions.
What is Coulure? Why is it caused?
- A condition in which vine experiences high proportion of failed pollination, therefore, poor fruit set.
- It is caused by CH imbalance during flowering. This may be caused by low photosynthesis rates (cold, cloudy cond. or extremely hot and dry), or over-vigorous shoot growth.
What is Millerandage? What are its causes?
- a condition in which there is a high proportion of seedless grapes. These are able to ripen, but will be smaller than normal berries. Therefore, yields will be smaller.
- Cause: cold, wet, windy weather during fruit set
What are the “suckers”?
non- fruiting shoots that emerge from old wood. they are normally removed
stages of grape development
- Early growth
- véraison
- ripening
- extra-ripening
What happens in the grape during the early-ripening?
- Tartaric and Malic acid accumulate
- some aroma precursors develop (methoxypyrazines)
- Tannin accumulation is encouraged by sunlight
- high water flow through the xylem
What is the effect of excess and limited water supply during the grape’s early ripening?
- Excess of water extends this period as shoot growth will be encouraged
- mild water stress will speed up this process, leading to a production of smaller grapes, but potentially, higher quality
What is the “lag phase”?
A slow down in grape ripening during véraison
What happens in the grape during véraison?
- Ripening slows down for a few days
- cell walls become more stretchy and supple
- chlorophyll is broken down and grapes change colour
When is green harvesting normally carried out?
During véraison, as the change in colour makes it easier to distinguish the less developed bunches
What are the benefits and risks of green harvesting?
- Benefit: achieve more concentrated (higher quality) grapes
- Risk: if there is a good water supply, the vine may compensate the loss by increasing the size of the remaining berried - dilution
What happens in the grape during its ripening?
- accumulation of sugars
- Malic acid degradation (encouraged by higher temp.)
- Dilution of Tartaric Acid
- Polymerisation of tannins (encouraged by sunshine)
- Anthocyanin synthesis (encouraged by sunshine)
- synthesis and accumulation of aroma precursors
- degradation of methoxypyrazines
- water flow is received only by the phloem
What happens in the grapes during extra-ripening?
- sugar transportation will stop
- berries will lose water through transpiration
- grapes will shrivel
- extra-ripe aromas will develop
define grape variety
a group of individual plants that can all trace back their lineage through a series of cuttings/layering to a single plant.
Define Clone
Each individual or group of vines that show a set of unique characteristics, even within the same variety
What are “founder varieties”?
Ancient varieties that have given birth to the enormous diversity that is grown today
what is clonal selection?
vines with positive mutations that are selected for future propagation
Factors that define the level of ripeness of the grapes
- Sugar levels
- Level of acidity
- profile of aromas
- Tannin ripeness
- wine style aimed for
Logistics factors (other than grape ripening) that influence the decision on harvest date
- Weather forecast
- availability of workforce
- disease pressure
- availability of vineyard/winery equipment
What is an intra-specific cross?
Cross of the same species
What is an hybrid?
A cross of two different vine species
What are the most commercially relevant hybrids for winemaking?
Orion, Phoenix, Regent, Rondo, Vidal Blanc
Examples of successful crossings
- Pinotage - Cinsault x Pinot Noir
- Muller-Thurgau - Riesling x Madeleine Royal
- Bacchus - Silvaner x Riesling x Muller-Thurgau
- Dornfelder
- St Laurrent
- Ruby Cabernet - Cabernet Sauv x Carignan
Examples of Teinturier grapes
- Alicante Bouschet
- Chambourin
- Colorino
- Petit Bouschet
Ways of propagating the vine
- Cutting
- Layering
Explain Field grafting
cuttings are grafted directly to already planted rootstocks. This is only practised in warm areas.
Also called chip-budding
What does “repiquage” mean?
It is a French term to describe the replanting of young vines among existing old vines. The reason for this is to replace a dead or ill vine
What is top-grafting?
A technique for changing varieties in a vineyard. The trunk is cut off at 500mm above the ground, a split is made, and two wedge-shaped pieces of the new variety inserted.
Cheap and quick alternative to replanting with a new variety
What are the characteristics of Phylloxera insect?
- Yellow aphid native to North America
- it is parthenogenetic - can lay eggs without male sexual attention , leaving up to 7 generations in a summer
- Its life circle adapts to its host
How does Phylloxera affect Vitis Vinifera?
It lays eggs below ground level and feeds on the vine’s roots, thus, weakening the plant by removing photosynthates and allowing damaging bacteria and fungi to further attack them
How does Phylloxera affect American Vine Species?
It can weaken the vines when it attacks their leaves, but these vines have roots that are uncomfortable to the insect, as their sap clogs up its feeding apparatus
When and where was Phylloxera first seen in Europe?
in 1863 in Hammersmith, London
Explain grafting
It is an ancient practice that takes advantage of the plants not having an immune system, thus, different varieties can grow as one.
Grafting involves the union of the scion and the rootstock. A callus is formed around this union which provides the cells through which vascular continuity is restored.
Both, scion and rootstock, maintain their genetic identity
Classifications to choose the correct rootstock
- nematode resistance
- Phylloxera resistance
- vigour
- drought resistance
- ability to withstand high soil lime content
Richard Smart’s Climate levels classification
- Macroclimate - Regional level
- Mesoclimate - subregion / vineyard
- Microclimate - individual vine level
GST Climate Classification
- Cool - GST 16.5°C or less
- Moderated - GST 16.5 - 18.5°C
- Warm GST 18.5 - 21°C
- Hot GST + 21°C
Climate classification by temperature and rainfall patterns
- Maritime - low annual differences in season temperatures. Rainfall is evenly spread throughout the year.
- Mediterranean - low temperature differences, but rain is concentrated in winter. Dry summers
- Continental - extreme differences between summer and winter temperatures. Short summers and cold winters
How does temperature affect bud-burst ?
- Bud-burst is stimulated by temperatures rising above 10°C
- it is best successful and uniform if there is a significant rise in temperature
- warm soils are associated with early bud-burst
- cold temperatures that bring frost at this period can cause extensive damage, and significantly reduce yields.
How does temperature affect flowering ?
- Warm temperatures (+17°C) promote successful and even flowering.
- cold damp conditions will result in poor fruit set - reduced yields
- not enough warmth may also result in less synchronised flowering leading to uneven ripening of the grapes.
how can extreme heat affect the vine?
- high temperatures increase the evapotranspiration of the vineyard
- if there is not enough water supply, the somata will close and photosynthesis will stop - stunting grape ripening and vine growth
What is the effect of sunshine on vine growth?
- Sunlight is essential for photosynthesis to happen
- Sunshine in spring is associated with successful flowering/fruitset
- sunshine throughout summer increases bud fruitfulness in the next growing season
Effect of sunlight on grape development
- promotes development of anthocyanins
- breakdown of methoxypyrazines
- greater tannin accumulation pre-véraison and further polymerisation post-véraison
- synthesis of positive aroma precursors/compounds
- sunshine warms the grapes, therefore, promotes malic degradation
- prolonged periods of sunshine and high temperature can lead to sunburn
Effect of Latitude on sunlight
- the lower latitude, the more sunlight hours per annum
- the lower the latitude, the more intense the solar radiation
- low latitudes will receive similar daylight hours throughout the year. High latitude ones have longer daylight hours during summer and shorter ones during winter.
Latitude range in which vineyards for wine production are normally located
Between 30 and 50 degrees north and south the Equator
Effect of altitude on temperature
- Temperature fall approximately 0.5-0.6°C per 100m rise
- at higher altitude there is quicker heat loss overtime - higher diurnal range
Effect of latitude on sunlight
solar and UV radiation is more intense at higher altitudes
Effects of “El Niño”
- high level of rainfall and risk of Hurricanes in South America and California
- Warmer and drier conditions in Washington, Oregon and Australia
Effects of “La Niña”
- warmer drier conditions in South America and California
- cooler wetter conditions in Australia, Oregon and Washington
Effect of winds in the vineyards
- sea breezes can moderate summer temperatures
- winds that have travelled over hot land masses will heat up the vineyard area
- they increase the evapotranspiration
- they dry out the canopy, reducing fungal diseases incidence
- strong winds can cause extensive damage
How can the soils characteristics affect the vine microclimate?
- Free-draining soils warm up quickly
- light-coloured soils reflect solar radiation on to the fruiting zone
- Dark coloured soils absorb more energy and re-irradiate it during the night
Effects of mist and fog in the vineyad
- they increase the humidity
- they reduce vineyard temperature
- they limit sunlight
What is transpiration?
Water loss of the vine through the somata on the leaves. It causes water from the roots to be pulled up to the upper parts of the plant
Effects of limited water supply
- partial somata closure
- in extreme cases - leaf loss and vine death
- mild water stress before véraison will speed up grape ripening
- water deficit after véraison can lead to early shrivelling of the grapes
Effects of plentiful water supply on the growing season
- encouragement of vegetative growth, establishment of large leaf area
- before véraison: delay of grape ripening
- after véraison: dilution of grape’s sugars/flavours
- damp soils will be cold, and waterlogged ones may kill the vine’s roots
- humid conditions will increase fungal disease incidence
Natural factors that affect water supply
- Rain
- Soil characteristics
- evapotranspiration rate
What are “rain shadow” regions?
Mountain ranges that cause water to condense (rain) as wind currents that carry humidity cool down as they travel upwards. On the other side of the mountain, regions are isolated from cooling and humid winds, crating dry and even semi-desert conditions
Soil characteristics that affect water availability
- water-holding capacity
- depth
- draining properties
How does slope affect the water availability for the vine?
slopes have a larger run-off surface,, therefore, less water penetrates into the soil.
Slopes usually have thinner soils, which reduces the area over which vines can obtain water
The reduced amount of organic matter in slopes reduces the water-holding capacity of the soils
What is the “evapotranspiration” of a vineyard?
It is the combination of water leaving the vine through transpiration and the water leaving the soil through evaporation . - the rate at which water is no longer available.
Under what conditions does the evapotranspiration experience it highest rates ?
in hot, dry, windy conditions.
name the sources of water for irrigation
- natural flowing water (rivers)
- natural static sources (pond or lake)
- man-made irrigation lagoon
- pumped from a bore-hole
Name the different types of irrigation
- Flood
- channel
- drip
- sprinklers
Advantages and disadvantages of drip irrigation
Adv. - high level of control over individual plots/rows - efficiency in water usage - low labour requirements - can be used for fertigation - can be used in slopes Dis. - quality of the water must be high - high initial investment - must be monitored to avoid blockages
Advantages and disadvantages of flood irrigation
Adv. - vines can be planted in their own roots - quality of water is not a problem - low cost (unless water cost is high) Dis. - labour intensive - extensive amounts of water needed - inefficient use of water - can only be applied in flat land
Advantages and disadvantages of channel irrigation
Adv. - quality of water is not an issue - more water efficiency than flooding Dis. - channels may get damaged by machinery/animals - can only be applied on flat land
Advantages and disadvantages of irrigation with sprinklers
Adv. - can be used for frost protection - do not block as easily Dis. - high evaporation rate - high investment - need high pressure pumps
Average water-holding capacity of sand, loam and clay
- coarse sand - 35mm/m2
- loam - 160mm/m2
- sandy clay - 200mm/m2
What is RDI?
Regulated Deficit Irrigation
vines are kept supplied with a level of water that is just below the one needed for maximum growth. Vines will therefore be less vigorous and expand their roots system.
This deficit is normally scheduled between fruit set and véraison
Advantages and disadvantages of practising RDI
Adv - economises water use - if correctly timed, it improves grape quality Dis. - reduces yield - cost increase in monitoring equipment
What is PRD?
Partial Rootzone Drying
One side of the vine’s roots is wetted, while the other one is kept dry. This pattern is alternated every 10 days.
The plant is confused into thinking it is water stressed, partially closing somata.
Factors that affect nutrient availability
- water availability
- soil pH
- soil life diversity
- soil texture
- topography
what are the most important nutrients for vines
- Nitrogen - component of chlorophyll and proteins
- Potassium - regulates water flow
- Phosphorous - important for photosynthesis
What is the soil texture
it describes the proportional content of the mineral particles of sand, clay and silt.
Important factors of the soil
- texture
- structure
- depth
- how it has been managed
What does the term “loam” refer to?
To soils that have equal levels of clay, sand and silt
What is the soil structure?
A term that describes how the mineral particles form aggregates. The size and stability of these will determine the drainage properties, root growth and workability of the soil
Factors that affect soil structure
- organic matter content
- amount and chemical nature of clay
- Content of Na and Ca
- Soil disturbance by cultivation
What is the effect of hummus in the soil?
- It bonds to clay forming good soil structure
- prevents soil compaction and allows air to penetrate
- improves water holding capacity, releasing it slowly
- traps nutrients
How does cultivation affect soil structure
- repeated cultivation exposes organic matter to faster decomposition which weakens soil structure.
examples of regions benefited by dark soils
- black basalt in Pfalz,
- dark-grey slate in Mosel
- dark schist in Belgium
Factors that affect soil health
- amount of living organisms
- availability of nutrients
- humus content
Types of fertilisers
- Organic - fresh or decomposed plant/animal material
- Inorganic - manufactured or extracted from ground
key points of Conventional viticulture
- use of mechanisation
- application of chemicals
- irrigation
- clonal selection
- monoculture
Key points of sustainable viticulture
- three lines of action - environmental, social and economic
- IPM
- proactive growers
- promotes biodiversity
- waste manage
What is the biological control
Introduction of natural enemies of a pest (predators or diseases) to let them control the problem
Key aims of organic viticulture
- improve soil health and microorganism population
- rejection of synthetic chemical use
- application of compost
- biological control
- promotes biodiversity
disadvantages of organic viticulture
- reduction of yields
- reliance of copper
- time and cost investment on certifications
Key points of biodynamic viticulture
- Organic practices as baseline
- vineyard practices are carried out according to cycles of the planets and the moon
- soil is the connection between the plant, the plant earth and other planets
- preparations to enhance the life forces of the farm
What are the most important Biodynamic vineyard preparations?
- Horn manure (500) - cow manure is stuffed into cow’s horn and buried into the ground throughout winter. the it is dynamised and sprayed. It catalyses humus formation.
- horn silica (501)- horn stuffed with ground quartz (silica) buried for six months, dynamised and sprayed to encourage plant growth.
- compost - activated’ by a series of starters added in tiny quantities which assist on the decomposition of the organic matter. - yarrow, chamomile, nettle, oak bark, valerian
management options to reduce the risk of sunburn
- canopy management to partially shade the bunches
- irrigate to reduce water stress
- use sunscreen spray or net to shade the grapes
- row orientation that reduces the impact of the hot afternoon sun
consequences of sunburn in grapes
- scar on the skins
- browning of the grape
- bitter taste
- higher susceptibility to fungal diseases
- in extreme conditions - grape death
Management options for Hail
- fire rockets into thunderstorms. Its silver iodide will cause rainfall rather than hail
- netting the fruiting zone (only applicable to areas with high levels of sunshine)
- Plant in different locations to lower the risk of losing the entire crop
What is “smoke taint”?
grapes that have been expose to fire smoke will absorb chemical compounds of the smoke, which will bind to sugars and act as aroma precursors during fermentation. These can give the wines a “smoky” or “plastic” flavour.
Management options for grapes affected by smoke taint
- winemaking techniques that are gentle in extracting compounds from the skins - hand-harvesting, gentle or whole bunch pressing, low fermentation temperatures, reduced maceration.
- Flash détente and reverse osmosis have also proven useful to reduce the effect.
Types of frost
- advection - very cool frost-carrying air blows into the vineyard region and displaces warmer air
- radiation/inversion - on clear still dry nights, in which there is no clouds or water vapour to trap heat. The heat irradiated by the earth and plant tissue escapes freely to the space and the surface quickly cool down. air above them will freeze, and collect close to the ground and on depressions.
Options to reduce the risk of frost
- site selection - plant on slopes, away from frost pockets
- later pruning to delay bud-burst
- plant late budding varieties
- train the vines high
- careful manage of the vineyard alleyways
Management options to reduce frost damage
- monitor the forecasts to act beforehand is essential
- Sprinklers (aspersion) - water will freeze around the vine and protect it from even cooler air temperatures
- wind machines - large fans which pull warmer air from above down to the ground. Effective if there is an immersion layer
- helicopters (same as above)
- Oil/propane heaters
What is the only protection against advection frost?
- use of sprinklers
How do nematodes affect vines ?
- physical damage by feeding off their roots
- transmitting viral diseases such as fanleaf virus
What are the most common nematodes?
dagger and root-knot
Management options against nematodes
- use of treated nursery plant material
- fumigation (banned in most countries)
- plough in a cover crop of mustard (contains biofumigant compounds)
- take samples of the soil before planting
- use nematode resistant rootstock
Management options against grape moths
- Insecticides
- Biological control - Bacteria that produces toxic substances, pheromones capsules for sexual confusion, or natural predators such as some spiders, parasitic wasps.
What are the most common grape moths?
How do they affect vines?
- Apple moth in Australia, Grape berry moth in America, European moth in the south of the continent.
- they feed on flowers and grapes
How do spider mites affect vines?
they feed on the surface cell of the leaves, causing decolouration of the leaves, reduction of photosynthesis, delayed ripening and yield reduction.
What are the most common spider mites in vines? in what conditions do they thrive?
- California - pacific spider mite
- Europe - red spider
- they thrive in dusty conditions
- they are most damaging when the vines are water-stressed
Management options against spider mites
- spray water or plant cover crops
- encouraging predatory mites
- specific pesticides
Management options against birds
- total netting
- scarecrow
- Falcons
How does grey rot infect the vine? in what conditions does it thrive?
- it is prevalent in areas with summer and autumn rain
- it overwinters in the form of sclerotia in old wood
- spores are transmitted by running or dripping water
- it can infect young tissue early in spring
- later, it is a secondary invader, affecting grapes that have been physically damaged
How does “bunch rot” occur?
When botrytis proliferates during flowering, it can get trapped in the middle of the bunch. It may stay dormant until grapes swell and more humid conditions occur. Then it will infect the bunch from the centre and cause substantial crop loss.
When does stem rot occur? what is the consequence?
- stems may be weak on vines with high yields, therefore, more prone to be infected
- it will cause bunches to fall to the ground
Management options against grey rot
- selecting thick-skinned grapes
- maintaining an open canopy
- fungicides at key moments (at the end of flowering, at bunch closure, veraison)
- Biological control - Bacillus Subtilis
Other than the suitability to produce grapes at the aimed quality, What considerations may affect the site selection decision?
- Price of land
- wine laws
- Proximity to towns/cities for labour, distribution centres, cellar door customer.
- distance to the winery
- source and cost of water if needed
- cost implications of the topography (mechanisation, installing drainage systems, frost protection, building terraces)
What are the aims when choosing vineyard location to produce high volume of inexpensive wines?
- Flat land to enable mechanisation
- fertile soils
- warm weather
- irrigation
- dry climate (to avoid fungal diseases that increase costs)
- cheap land
What are the aims when choosing vineyard location to produce premium wines?
- wine style aimed for will be the most important factor
- in cool climates maximising sun exposure is normally the aim - sloping sites, dry soils, adequate aspect, etc.
- in warm climates exposure to cooling influences - altitude, sea breezes, mists
activities that may be carried out when preparing the site
- uproot vines/plants
- weed control
- soil amends
- landscaping works
- ripping/subsoiling
- installing drainage systems
- installing irrigation systems
- planting windbreaks
- plant cover crops
- fencing, bird netting
Considerations when choosing planting material
- time of budding
- annual life-cycle
- tolerance to drought
- resistance to disease
- winter hardiness
- vigour
- yield
- law
- availability
- market demand
- cost
Factors that determine the decision on vine density
- Climate
- water availability
- cost
- vigour of the vines
- trellising system aimed for
- cost of land
- access needed to the vineyard (machinery)
What are the cost implications of vine density?
- high density vineyards: more cost in planting material, will come into full cropping potential earlier
- low density vineyards: more permanent wood to be developed, will take longer to stablish. if trellised, they are cheaper to maintain and easier to mechanise
What determines the row width?
- largest piece of machinery that needs to fit down the row
- rows must also be wide enough to avoid shadow on the next row
- machine harvested vineyards also need wide headlands
What row orientation provides the most even sun exposure to the canopy?
north- south orientation
What are the aims of the canopy management?
- promote balance between the vegetative and the reproductive functions
- produce the aimed wine style at the right yield and cost.
- ensure even ripening throughout the vineyard
- reduce fungal disease incidence
Factors that determine the decision of training and trellising system
- vigour of the vine
- topography
- need for mechanisation
activities that the canopy management covers
- vine training
- winter pruning
- shoot thinning
- summer pruning - shoot devigoration, shoot positioning, disbudding, leaf removal, green harvesting, pinching
functions of the training and trellising systems
- physical support of the vines
- aid mechanisation and vineyard access
- provide the best environment for grape ripening
- ensure that the vines keep cropping for several years
- produce grapes at the aimed quality at the right quantity and cost.
Vine training options
- head training - relatively little permanent wood - trunk + short stubs
- cordon training - larger amount of permanent wood - trunk + one or more horizontal “arms”
What is pruning? What is the importance of winter pruning?
pruning is the removal of unwanted parts of the plant. Winter pruning determines the number and position of the buds that will break and grow in the coming growing season.
name the types of pruning
Spur pruning cane pruning (Guyot)
What does Guyot refer to?
Name given to cane replacement pruning
Explain spur pruning
spurs are stubs of wood carrying short pieces of canes bearing one or more fruiting buds.
They can be spread along a cordon, or around the top of the trunk
Advantages of spur-pruning
- number of buds retained per row metre is higher
- number of buds retained can be adjusted every year
- for any given yield, it allows wider rows
- in cordon trained vines, it aids mechanisation
- pruning can be carried out with less experienced staff
- spurs are better protected against frost
Disadvantages of spur-pruning
- buds are near to old wood - more prone to fungal diseases
- canopy will be dense
- varieties with blind buds near old wood will have lower yields
- cropping potential is too high for regions with adverse weather conditions
explain cane pruning
- a cane is a long section of one-year-old wood that is typically laid down and tried to the trellis. number of buds can vary from 8 to 20. one or two thumbs are also kept to provide starting point for the replacement of canes the following year.
- there are single, double and four-cane guyot systems
Advantages of cane pruning
- buds are born away from old, disease-prone wood
- buds are evenly spaced - avoids crowded canopy
- canes can be arched to avoid apical dominance
- avoids blind buds
Disadvantages of cane pruning
- no opportunity to increase fruiting buds
- time-consuming
- requires knowledgeable pruners (more expensive)
- buds are more at risk of frost damage
- it is very difficult to mechanise
What is apical dominance?
tendency of buds more distant to the trunk to break first and stronger. some varieties are more prone to it
What are “bush” vines?
What growing environment is it best suited to?
Head trained, spur-pruned untrellised vines.
- ideal system for hot, sunny, dry regions, where the vine’s vigour is low, and the canopy will partially shade the grapes
What does VSP mean?
Vertical shoot positioning
Why have complex training systems have been designed?
To be able to produce high quality grapes at high yields from over-vigorous vines. They split the canopy in two, to maximise light interception, making better use of vineyard space and resources.
What do downward-training systems consist of?
shoots of the vines are persuaded to grow in the opposite direction of their natural tendency. As a result, they have shorter internodes, smaller leaves, are less vigorous and have less number of potential flowers.
Examples of downwards training systems
- Geneva Double Curtain
- Scott Henry
- Sylvoz
Why are “vignes basses” common in regions like Burgundy?
Because the low overall height (1.2m) allows the use of straddle tractors, therefore, vines can be planted at very high densities and with narrow rows. Which is particularly valuable in such expensive land.
Why has the decision on harvest date changed the approach in modern times?
- generally warmer climate, which makes it easier to ripen grapes in traditional cool regions
- better viticulture techniques
- a focus on tannin and aroma ripeness
what is the common level of Brix degrees of grapes at harvest time? (dry still wines) to which alcohol level does it translate?
19 - 25 degrees, meaning 11-15% potential alcohol
How can Machine-harvesting results be improved?
- selecting out undesirable fruit by hand before harvest
- using modern bow-rod shaking machines (more gentle)
- rigorous sorting on arrival at the winery, or using machines with optical sorting devices
- using machines that crush and add SO2 while harvesting
Advantages of machine harvesting
- Fast and substantially cheaper
- Avoids issues with lack of workforce
- grapes can be picked up at night
- vast extensions of land can be harvested quickly - allows snap decision to act according to weather, ripeness and disease pressure
disadvantages of machine harvesting
- high equipment investment
- requires qualified operator
- if equipment rented - high demand at harvest time
- unsuitable to steep slopes
- still less gentle than hand harvesting
- unsuitable for delicate white wines
- it is not possible to obtain whole bunches
advantages of hand-harvesting
- crushing can be avoided
- whole bunches can be used if required
- high level of selection
- harvesters can cope with rugged landscape
Disadvantages of hand-harvesting
- large amounts of reliable workforce is needed (scarce in many areas)
- workforce has to be trained and supervised
- it is slow
- has to be with daylight
Key points of precision viticulture
- It uses data collected from the vineyard to respond to changes from plot to plot/ row to row.
- variable-rate application technology
- It aims to respond to changes in the vineyard, but also to reduce their impact
- also used to identify different quality zones within the same vineyard
Ways of collecting data for precision viticulture
- remote - sensor on aircraft
- proximal - sensors on a tractor or harvester in the field.
advantages of precision viticulture
- detailed understanding of variations that affect yield and quality
- ability to tailor a wide variety of interventions to individual blocks
- quality and yields can be significantly improved
- unnecessary interventions can be avoided
What does continentality mean ?
it is a measure of the difference between the annual mean temperatures of the hottest and coldest months. Regions that are isolated from the influence of large bodies of water have high continentality, and experience extreme temperatures to both ends in winter and summer.
What does the term “weather” describe ?
A region’s weather is the annual variation that happens relative to the climatic average. Some regions experience greater variation in this pattern than others. (vintage variation)
Effects of Climate change in grape growing
- bud-burst occurs earlier
- ripening process is quicker - higher alcohol in wines
- lower pH in grapes and final wine
- harvesting time is always a compromise between sugar and acidity, and tannin and aroma ripeness
- “typical” aroma characteristics of certain regions are changing
- regions that were too cool in the past are able to successfully ripen grapes
- some classic regions are now too warm for wine production
- drought is a serious problem and many vineyards have been abandoned for this reason
- extreme erratic weather creates greater vintage variation and significant crop loss at some years
How much water do vines normally need?
- 500 mm/year in cool climates
- 750mm/year (at least) in warm regions
management options when there is drought
- irrigation system should be designed prior to planting , afterwards can be too disrupting for established vines
- choose drought-resistant rootstocks - 110R and 140R
- choose drought-resistant varieties - Grenache
what are the effects of excessive rainfall?
- excessive vegetative growth and delay of grape ripening
- promote the development of fungal diseases
- waterlogging if soils are not sufficiently free-draining - impeding root growth and respiration
- compactation of the soil, making them difficult to work and uncontrolled water run-off
- it makes vineyard work too difficult
Management options for excess of water
considerations when designing the vineyard:
- plant on slopes
- plant on free-draining soils
- build an artificial draining system prior to planting
- complex training systems
Effects of untimely rain during the growing season
- during flowering - millerandage and coulure
- summer - excessive vegetative growth and delayed grape ripening
- harvest time - grapes swell and eventually split. Grey rot pressure and harvest work will be difficult to carry out.
name mammals that can be pests in different parts of the world
- wild boar, deer, rabbits, kangaroos, raccoons , baboons
symptoms of powdery mildew attack
affected parts show dull grey patches which turn black as they advance
What is the name of the fungus that causes Powdery Mildew?
Erysiphe Necator, also known as Oidium Tuckeri
How and when does powdery mildew spread?
- it overwinters in buds and canes, and then attacks the young green parts of the vine in spring
- The growth rate depends on the temperature - 25C is ideal
- it thrives in shady conditions
- it does not require high humidity
Management options against powdery mildew
- keep an open canopy
- sulphur applications prevents and treats the disease
- systemic fungicides- they penetrate the vine tissue
What is the name of the fungus that causes Downy Mildew?
Peronospera
How does Downy mildew spread and attack the vine?
- It needs rainfall and warm temperatures - 20C
- it attacks the green parts, especially young leaves and flowers, penetrating the vine tissue.
Symptoms of Downy mildew attack
yellow circular oil spots and white downy growth in the underside of the leaves
Management options against downy mildew
- Bordeaux mixture - copper sulphate + lime - the traditional treatment
- other copper-based sprays
- fungicides
- good drainage and open canopy
Vine diseases/pests that were introduced from North America
- Downy Mildew - last quarter of 19th century
- Powdery Mildew - mid-1800s
- Phylloxera - 1860s
- Pierce’s Disease
What disease is known as “Dead arm”?
Eutypa Dieback
How does Eutypa Dieback spread and infect the vine?
- its spores are spread by wind over long distances
- it infects pruning wounds, attacking trunk and old wood
- it becomes active in moderate temperatures during rain
Management options against Eutypa Dieback
- Pruning late and use fungicide on pruning wounds
- affected trunks are cut back and treated with fungicide
- dead wood must be burnt to stop the spread
- Biological control: Bacillus Subtillis
In what conditions does Phomopsis attacks?
In years with cool and wet springs, followed by high humidity and moderate temperatures
How does Phomopsis affect the vine?
- it infects canes and leaves
- canes whiten and break easily.
- shoots growing from affected canes develop brown cracks at their base
What are the symptoms of Esca infection? What are its effects?
- Tiger-striping of the leaves and spotting inside the wood
- yield reduction
- it kills the vine within a few years
In what conditions does Esca disease thrive? how does it infect the vine?
- it is prevalent in warmer and dryer regions. - Southern Europe and California
- in infects the vine through pruning wounds
Management options against Esca Disease
There is no chemical control. It can only be prevented:
- sourcing disease-free stock
- using less detrimental pruning techniques
- not pruning during rain
- quickly remove pruning from the vineyard and disinfect wounds
