Ch. 0 – Viticulture Flashcards
Most common species of vine
Vitis Vinifera
Vitis Lambrusca
Vitis Riparia
Vitis Berlandieri
Vitis Rupestris
Name parts of vine
Tendril
Lateral Shot
Inflorescence
Leaf
Compound bud
Main Shoot
Cane
What is the lenght of stem between nods called?
Internod
What does stem transport?
Water and solutes (substances dissolved in liquid - minerals and sugars)
Explain compound bud
Also called latent bud
Form in one growing season and break open in the next one
Primary bud opens first (followed by secondary or tertiary if necessary)
Explain prompt bud
Form and break in the same season and produce lateral shoots
Main functions of lateral shoots
Back up if main shoot is damaged.
Additional source of leaves for photosythesis
May have inflorescences (second crop) those ripen later or may be removed.
Explain photosythesis
Stomata (pores) open on underside of the leaves letting water diffuse out and carbon dioxide to enter.
Transpiration - transport of water from soil and roots back to leaves
Stomata closes if vine has water stress
Describe composition of grape berry
Pulp - water, sugars, acids and some aroma compounds and aroma precursors
Skin - high concentration of aroma compounds and precursors, tannins and colour compounds
Seeds - oils, tannins and embryo for new plant
Bloom - waxy coating of skin
Stem
2 kinds of vine propagations - explain
Cuttings - section of vine that is planted and grows as new plant. Can be grafted on selected rootstock and treated in nursery against deseases.
Layering - Establish neighbouring vine’s shoot is buried in the ground. New vine grows on its own roots.
Both methods are geneticaly identical to the parent (vines from seeds are not)
Explain clonal selection
Vines with favourable characteristics are propagated in nurseries by cuttings.
Explain mass selection (Selection Massale)
Grower takes cuttings from best performing vines in his vineyard and propagate them by cuttings (may graft them on rootstock)
Own unique planting material
Increases diversity
Costly in terms of time and labour
Possible spread of diseases (from parent)
New vines from seeds
Cross X Hybrid
Cross - parents from the same species
Hybrid - parents from different species
Dormancy (temperatures, hazards, management)
Below 10 degrees
Below -15 degrees hazard of damage or killing vine
Unusual warm can trigger budburst
Winter pruning
Budburst (temperatures, factors, hazards)
Temperature above 10 degrees
Continental climate advantageous with large winter/summer difference - uniform budburst
Maritime climate caìn be less synchronized
Other factors: temperature of soil (sand warms up quickly) and grape variety
Hazard of frost and cold days
Reasons of low carbohydrate levels in roots from previous season
Excessive leaf removal
Water stress
Mildew infections
High crop loads
Shoot and leaf growth stage (needs)
Stored carbohydrates from previous season
Warmth, sunshine, nutrients and water
Petioles
Base of leaf stalks where new buds develop
Fruitfullness
Number of inflorescenses
Describe pollination
Pollen-lade stamens (consisting of anther and filament) are exposed.
The pollen grains are shed and land on the moistened stigma surface
They germinate, each producing pollen tube
Pollen tubes penetrate stigma and then the ovule in the ovary.
Pollen tube delivers the sperm cells which fertilizes the egg in the ovule
Ovule forms up to 4 seeds
The wall of ovary enlarges to form the skin and pulp of the grape
Conditions for successful flowering
(timing, temperatures
8 weeks from budburst (temperature dependent)
min 17 degrees
sunlight, nutrients, water
adverse conditions: rain, clouds, cold temperatures
Pollen germination needs temperature of 26-32 degrees
Coulure
Grape bunch in which fruit set has failed for high proportion of flowers
Imbalance of carbohydrate levels (low rates of photosythesis - cold, cloudy, hot weather, water stress OR vigorous shoot growth)
Grenache, Malbec, Merlot, Cabernet Sauvignon are the most susceptible
Millerandage
High proportion of seedless grapes in bunch - smaller grapes
lower volume of wine or unequal ripeness
Usually from cold, wet, windy weather at pollination and fruit set
Chardonnay, Merlot are susceptible
Methoxypyrazines
contribute to herbaceous aromas/flavours
Sauvignon Blanc, Cabernet Sauvignon, Cabernet Franc
Xilem
Transport tissue which gets water and nutrients from roots to other parts of plant
Grape berry formation
what is created, what is needed
Tartaric and malic acid
Aroma compounds and precursors (Methoxypyrazines)
Tannins
Water intake is high (too much water can triger leaf growth)
Mid water stress speeds up this stage and reduces size of grapes (better quality)
Veraison
Colour change
growth slows down for few days (lag phase)
Chlorophyll in skin cells is broken down and grapes start to change colour
Due to the systhesis of anthocyanins
Factors influencing ripening stage
Grape variety
Climatic conditions
Management of vine and vineyard (heavy crop loads, excessive shading)
Time of harvest
Ripening stage
Sugar and water accumulate
Acid levels fall (tartaric acid is the same, malic acid drops due to use for respiration during ripening - respiration is slower in cooler regions -higher acidity)
Tannins, colour and aroma compounds and precursors develop
Methoxypyrazines levels drops (unless it is cloudy or grapes are too shaded)
Tannins polymerise - soften
Anthocyanins increase with sunshine and temperatures between 15 and 25
Conditions for photosynthesis
18-33 degrees
sunlight levels that are above one third of full sunshine
Water stress can lead to stop of photosynthesis
Phloem
Tissue which transports sugars from the leaves to other parts of the vine
Transportation by xylem slows down at ripening
Optimal ripeness
Balance of sugar, tannin and aroma ripeness
Geen shoot lignification
Becoming woody and rigid - from one-year-wood to cane
Optimum temperature for fruit set
26-32 degrees
Anthocyanin synthesis
definition and temperatures
development of colour
optimum temperature 15-25 degrees
The effects of sunshine
Needed for photosynthesis
reduction of methoxypyrazines
accumulation of tannin before veraison and polymerization after
creation of aroma compounds and precursors
increased use of malic acid for respiration - lower acidity levels
terpenes
Fruity and floral aromas
Grapey aromas in Muscat
Polymerisation of tannins
softening, less bitterness
Influence of latitude
Lower lattitudes - more and stronger solar radiation
radiation travels through less atmosphere and falls on larger angle (stronger)
Hours of sunshine during the year are more stable
higher sugar, lowe acidity, riper aromas, higher but riper tannins, more colour intensity
Lattitude for growing grapes
Between 30 and 50 on each side of Equator
How much temperature falls each 100m?
by 0.6 degrees
Diurnal range
difference between day and night temperatures
Effect of altitude
Cooling influence in high altitude
Sunshine is more intense in high altitude
Ultraviolet radiation is also greater (promotin anthocyanins and tannin synthesis)
High diurnal range
Effect of diurnal range in high altitude
Air absorbs some energy and warmth from the soil and some heat is retained at night.
At high altitude air is thinner and holds less moisture, therefore heat rapidly escapes leading to cool nights.
Slope aspects with the most sun exposure
South for nothern hemisphere
North for southern hemisphere
Importance of aspect and steepness of slope
Increased importance in higher latitudes because solar radiation hits Earth in low angle.
The slope increases the angle therefore increasing the intensity of heat and light
Extention of growing season
In warm climates it may be desirable to limit the heat - planting on slopes which face away from sun
East facing vineyards benefit from morning sunshine (less moisture, longer hours of vine growth)
Shallower and better drained soils with less nutrients
Shelter from winds, rain and frost
Danger of soil erosion
Effect of proximity of water
Water heats up and cools down slower than dry land
Day - water remains relatively cool and lowers the temperature in the area. Cool air from above water is drawn to the land to replace the warm air as it raises, resulting in cool humid afternoon breezes
Night - water retains the warmth and keeps local area warmer
Cold/warm ocean currents
Radiation reflection from the water surface (especially high latitude vineyards)
El Nino
Climatic cycle which occurs every 3-7 years
Pacific Ocean becomes warmer and causes a lot of rainfall and risk of hurricanes in South America and California
Pacific Northwest (Washinghton, Oregon) get warmer than average conditions and drought
Australia and Western side of Pacific - warm and drought
La Nina is the oposite
Effect of wind
cooling or warming influence
Cooling breezes near to body of water (moderating diurnal range)
Valleys - stronger winds (possibility of funnelling between mountain ranges)
Warm breezes from winds travelling over hot land
Reduction of humidity (fungal diseases)
Increase of evaporation rate (increse of need of water)
Hazard of damage by wind (rows of trees as windbreakers on sides of vineyards)
Soil and temperature
Free draining soils (sand, stones) warms up quick in spring - encouraging early budburst and longer growing season (spring frost hazard)
Warm soils encourage root growth (ability to absorb more water and nutrients)
Light coloured soils (chalk) reflect some of energy from solar radiation
Dark coloured soils absorb more energy and re-radiate it when temperatures are cooler (at night)
Mist, fog and clouds
Mist is formed by tiny drops of water colecting in the air above ground or water. It is formed when warm air is rapidly cooled, causing water vapour in the air to condense
Regular cloudy weather can slow down sugar accumulation and acid degradation (beneficial in warm climate for early ripening varieties)
Increase humidity - fungal diseases or noble rot
Annual water need for vine
500mm in cool climate
750mm in warm climate
What is water in vine needed for
For turgidity (so it does not wilt)
Photosynthesis
Regulating temperature
Solvent for nutrients from soil
Healthy growth and ripening
Explain transpiration
Water vapour diffuses out of the stomata (pores underside of leafs)
The water loss causes water to be pulled from the soil
Stomata
Little pores underside of the leaves which vapour water
Lets carbon dioxide an oxyget diffuse in and out
Over supply or under supply of water
Under-supply
stomata closes to save water. Photosynthesis stops, growth stops
Grape shrivelling before harvest (or under-ripe grapes)
Over-supply - vigour (good in spring)
Problem in mid summer as it prolongs and compromise ripening
Excessive shading
Diluting of sugar in grapes before harvest (or even grape splitting)
reduced formation of anthocyanins, tannins and aroma compounds, less tannin polymerisation and higher level of methoxypyrazines
Humid conditions due to poor ventilation
Problems of excessive vegetative growth
vigour (good in spring)
Problem in mid summer as it prolongs and compromise ripening
Excessive shading
Reduced formation of anthocyanins, tannins and aroma compounds, less tannin polymerisation and higher level of methoxypyrazines
Humid conditions due to poor ventilation
Water and soil
Soil drainage and water retention depends on structure and texture of soil
water logged soils are harmful to wine (reducing the amount of oxigen for roots which slows growth)
Warm soils speed up bud burst (longer season)
Slopes - shalower soil with less nutrients, less water due to run off from the slope, problem with erosion
What is evaporation rate and what does it depend on
Amount of traspiration from the wine combined with the evaporation of water from the soil
Depends on temperature, humidity and wind
Nutrients
Nitrogen
Potassium
Phosphorus
Calcium
Magnesium
Sulfur, manganese, boron, copper, iron, zinc
Nitrogen
Component of proteins and chlorophyll (essential for photosynthesis)
essential for vine growth, impact on vigour and grape quality
High levels - excessive vegetative growth (hindering ripening, fruit shading, poor ventilation)
Low levels - reduced vigour (yellowing of leaves) grapes can be difficult to ferment
Restricted supply procudes higher quality grapes
Potassium
Essential for vine growth and water flow
High levels - problems with uptake of magnesium (reduced yields and poor ripening) high potassium in grapes (high pH in wine)
Low levels - low sugar accumulation, reduced yields and poor growth
Phosphorus
Important for photosynthesis
(only needed small amount and usually sufficient)
Low levels - poorly developed root system (poor water intake, low yields, reduced growth)
Calcium
Important for structure of plant cells and in photosynthesis
Low levels - negative influence on fruit set
Magnesium
Found in chlorophyll, key role in photosynthesis
Low level - (rare) reduced yields and poor ripening
Soil and nutrient availability
Nutrients for vine dissolve in water which is then taken up by the roots
Different nutrients are available at different pH levels
Soil texture and nutrient holding capacity (clay - high, sand - low)
Slopes have more shallow soil with less nutrients
Fertilizers, manure, compost
Chlorosis
Lack of iron
Condition in which leaves turn yellow and photosynthesis stops
Explain mineralization
Vine cannot take up organic nutrient compounds (manure, compost) but needs inorganic ones.
Soil organisms are feeding on organic material and converting it into inorganic material
Texture and structure of soil
Texture - proportion of the mineral particles of sand, silt and clay.
Clay - fine texture, effective water holding capacity
Sand - good drainage, poor water retention, easy for roots to grow through
Silt - intermediate size
Loam - moderate proportion of sand, clay and silt
Rocks and pebbles - improve drainage but lower water holding capacity
Structure - how the mineral particles in the soil form aggregates (crumbs) The size, shape and stability is important for drainage, root growth and workability of soil
Definition of climate
Annual pattern of temperature, sunlight, rainfall, humidity and wind averaged out over several years (generally 30)
Climate models
Growing degree days (GDD)
The Huglin Index
Mean temperature of the warmest month (MJT)
Growing season temperature (GST)
Koppen’s Classification
Growing degree days climate classification
Amerine and Winkler (1944)
Substract 10 (temperature below vine cannot grow) from average mean temperature of a month in the growing season.
Multiply by number of days in the month
Make same calculation for each month in the growing season
Add together to get GDD (any months with negative value do not count)
Grouped into 5 zones Winkler Zone I is the coolest
The Huglin Index
Similar to GDD but the calculation takes into account both mean and maximum temperature and the increased day lenght experienced at higher latitudes
Split into ranges with the most suitable varieties
Widely used in Europe
Mean temperature of the warmetst month (MJT)
Smart and Dry (1980)
Uses mean temperature of July (or January) as well as measures of continentality, humidity and hours of sunshine.
Divided into 6 bands
Growing season temperature (GST) climate classification
Mean temperature of the whole growing season
Split into bands
Close to GDD but easier to calculate
Koppen’s Classification (climate classification)
(1900) Considers both temperature and rainfall patterns (only for temperate zones and not tropics)
Maritime - low difference between summer and winter temperature, even spread of rainfall (Bordeaux)
Mediterranean - low difference between summer and winter temperature, dry summers, wet winters (Napa, Coonawarra)
Continental - extreme difference between summer and winter temperatures, short summers, cold winters, rapidly changing temperatures in spring and autumn (Burgundy, Alsace)
Cool climate - average GST 16.5 or below
Moderate climate - 16.5 - 18.5
Warm climate - 18.5 - 21
Hot climate - more than 21
Monoculture advantages and diasdvantages
Advantages:
Ability to mechanize
Reduction of competition between other plants
Ability to tend to specific needs of the grape variety planted (irrigation, nutrition level…) to increase yields while reducing costs
Disdavantages
More prone to diseases and pestes - more treatments of protection
Nutrients can be depleated - no ecosystem to replenish them
Residual chemicals - environmental damage
Conventional Viticulture
Raising production levels
Reducing labour requirements
Mechanization
Chemical inputs
Irrigation
Clonal selection
Monoculture
Sustainable viticulture
Ecomonic, social and environmental sustainability
Aims to promote natural ecosystems, maintain biodiversity, manage waste, minimise applications of chemicals and energy use, and reduce impact of viticulture on environment.
Encourages in-depth understanding of lifecycle of vine and pests and monitoring weather.
Prevent and predict pest or diseases (fewer applications of chemicals needed)
Integrated Pest Management
Integrated Pest Management (IP)
Lutte Raisonee
Insights of organic viticulture, but prepared to spray when necessary.
Identifying and monitoring pests, setting preventative measures, evaluating and implementing control options (if prevention was not effective and treshold levels were exceeded)
Reduces cost and vine’s resistance to treatments
Sustainable viticulture
advantages and diadvantages
Advantages:
Attention to economic social and Environmental impact
Scientific understanding of threats
minimalisation of interventions
Cost saving
Disadvantages
Term is not protected and can be used to promote wine without any standards
Nationwide standards can be set too low
What is biomass in the soil
The total quantity of organisms in a given area or volume
Organic Viticulture
Seeks to improve soil and range of microbes and animals within it. Therefore increase the health and disease resistane of the vine. Rejects use of synthetic fertilizers, fungicides, herbicides and pesticides.
Application of compost (slow release of nutrients, improved structure, increase of biomass)
Cover crops to combat erosion, improvement of life of the soil, biodiversity, green manure (ploughing them in soil)
Natural fertilizers (animal dung, natural calcium carbonate etc.) restoring natural balance of soil
Monoculture is reduced by cover crops, pranting hedges and islands of biodiversity
Monitoring weather and using copper sulfate and sulfur to combat mildew
Natural predator introduction (Bacillus Subtilis can compete with Botrytis on leaf space)
Sexual confusion - pheromone tags which disrupt mating patterns of insects
All certification bodies for Organic viticulture need to be certified by:
IFOAM
International Federation of Organic Agriculture Movements
% of Organicaly grown vineyards in Europe
10% in Europe, accounting for 85% in the world
Organic viticulture
Advantages and disadvantages
Advantages
Central aim of grape grower is health of soil and disease-resistance of vine
Reduction in number of chemical treatments
Saving on cost of synthetic chemicals
Diadvantages
Small reduction in yield
Significant redustion of yield in difficult vintages
Increased reliance on copper sprays - heavy metal build-up in soil
Cost and time expended on certification
Biodynamic viticulture
Based on Rudolf Steiner and Maria Thun
Organic practises with philosophy and cosmology. Adaptation of practises to coincide with the cycles of planets, moon and stars
Calendar which advise growers on root, leaf, flower, or fruit days to indicate best days for certain activities
Homeopatic remedies ‘preparations’ are used
Increased labour costs
Preparations in Biodynamic viticulture
500 (horn manure) - stuffing cow manure into horn and burying the horn in soil over winter. Then dug up and content is dynamised (stirring the content into water - creating vortex and then reversing it) so the water memorises the power of the preparation which can then be strayed into soil as homeopatic compost
501 (horn silica) - filling cow horn with silica (quartz) and burying it for 6mths. Then dug up dynamised and strayed into soil
502-507 (compost) - Series of starters which are added to compost to activate it (yarrow, chamomile, nettle, oak bark, dandelion, valerian prepared in different ways - yarrow in deer’s bladder). This assists to the decomposition of compost
Ashing - Spreading ashes of weed seeds or harmful animals to ward off these hazards
Traditional chemicals to spray such as sulfur and copper are also used.
Certification body for Biodynamic viticulture
Demeter
Organic certification is a baseline
Precision VIticulture
Makes use of data colleced from the vineyard (soil, vigour, topography, plant growth) to respond to changed from plot to plot.
Data are collected by sensors by plane (remote) or by tractor or harvester (proximal) use of GPS or GIS presents it visualy in form of map.
Interventions in the vineyard such as pruning, treatments, irrigation and harvesting are carried out precisely with the aim of producing best quality and yield, reducing environmental impact and lower cost on treatments.
Large scale viticulture only
Can also identify quality zones
Advantages and diadvantages of Precision Viticulture
Advantages
Detailed understanding of variations in the vineyard
Ability to tailor a wide range of interventions
Disadvantages
Initial cost and investment
Cost of software and consultancy of trained staff to interpret the data
Site selection
Question of style, price and quality
Price of land
Implication of topography and location - labour availability, mechanization, access to the vineyard, proximity to towns
Soil preparation
Checking soil drainage, structure, mineral composition and presence of pests and weeds
Plough pan breaking (impervious layer of soil caused by years of ploughing at the same depth) has to be broken down (subsoiling)
Old roots have to be removed (and burned to avoid deseases)
Farmyard manure, compost and fertilizers may be applied.
pH can be adjusted (too acidic soils are adjusted by Lime - calcium based)
Choice of grape variety for establishing vineyard depends on:
Suitability to climate:
Time of budding
Duration of annual life-cycle (time of ripening)
Tolerance of drought
Resistance to disease
Winter hardiness
Vigour
Other factors:
Style of wine
Yield
Cost (ex. Pinot Noir is prone to disease and difficult to grow)
Law (specific grapes allowed)
Availability
Market demand
Choice of rootstock
Usually hybrids to take advantage of both species
Mainly against Phylloxera
Criteria:
Pests (against nematodes)
Water tolerance (drought, water logged soils, salinity)
Soil pH
Vigour (to take advance on ripening etc.)
Rootstock against root-knot nematodes
Ramsey and Dog Ridge (Vitis Champini)
Rootstock for drought tolerance
Hybrids of V. rupestris and V. berlandieri
Rootstock for water logged soils
Riparia Gloire (V. Riparia
Rootstock for high salinity
V. berlandieri 1103 Paulsen
Rootstock for acidic soils
Hybrids of V ruperstris and V. berlandieri
99R and 110R
Rootstock for soils with high lime content (high pH)
V. berlandieri 41B
Low vigour rootstock
V riparia 420A and 3309C
advance ripening
High vigour rootstock
V. rupestris 140R
for unfertile and dry soils
Soil health (factors)
Structure of the soil (drainage, water-holding capacity, sufficient oxygen, resistance to erosion, ability to allow roots to penetrate to sufficient depth)
Amount of organic matter and humus
Number of living organisms
Amount of available nutrients
Nutrition management techniques
Fertilizers (organic x mineral)
Soil cultivation
Herbicides (pre-emergence x contact x systemic)
Animal grazing
Cover crops
Mulching
2 types of fertilizers
Organic
from flesh or composted plant or animal material
Cover crops can be plought in (green manure)
Cheap or free
High in hummus - good for structure and water retention
Organic form provides nutrients for soil organisms which turn it into inorganic form
Requires a lot of labour
Nutrients are available gradually
Expensive to transport and spread
Mineral
Extracted from the ground or chemically manufactured
Single nutrient or package (more tailored)
Already inorganic form (immediately available)
No benefit for soil organisms or soil structure
More expensive but cheaper to transport and spread
Explain soil cultivation
+advantages and disadvantages
Method of weed control that involves ploughing the soil to cut or disturb the weeds’ root systems
Advantages:
No chemicals
Crops are incorporated into the soils at the same time as removing weeds
Diadvantages:
Repatedly it can damage soil’s structure and ecology by destruction of habitats
It can increase wine vigour as there is no competititon
Types of herbicides and their advantages and disadvantages
Pre-emergence herbicides
Contact herbicides (kill green parts)
Systemic herbicides (taken in by the leaves and kill the whole plant)
Advantages:
Cheap in terms of labour and machinery
highly effective
less damaging to soil structure than cultivation
Disadvantages:
Risk of poisoning of operator, consumer and environment
Do not encourage vineyard ecosystems
Weeds can become resistant
Can increase vine vigour (no competition)
Not allowed in organic viticulture
Advantages and diadvantages of animal grazing
Advantages:
No chemicals used
Provide manure
Source of meat
Disadvantages:
Vines must be trained high (risk of eating plant and fruit)
Labour for taking care of animals
Often susceptible to pesticides
Cover crops
Specificaly planted or allowed to grow to have beneficial effect on the vineyard
Surpress weeds Improve soil structure Compete with vine for nutrients and water Enhance biodiversity Provide surface to drive on Can be used as green manure Must be managed too No use of chemicals Not suitable for steep vineyards as slopes are becoming slippery
Usually legumes or cereals
Mulching - explain and elaborate on advantages and diasdvantages
Spreading of matter onto the vinyard soil to suppress the growth of weeds
Usually straw or bark chips
Advantages:
No use of chemicals
Can reduce water evaporation
Can be ultimately cource of nutrients and hummus (promotes biological activity and structure)
Diasdvantages:
Bulky - expensive to transport and spread
Only effective as thick layer
Can increase vigour too much as there is no competition for water
Water sustainability in the vineyard
Water efficient irrigation systems and techniques
Monitoring of water levels
Drought resistant varieties and rootstocks
Reducing evaporation (mulching)
Reducing competition (removing weeds)
Increasing humus levels to improve water retention
Promoting growth of roots deep into soil (through cultivation)
Types of irrigation
Drip irrigation
Positioned far enough from vines to enourage the roots to grow and seek water.
Economic use of water
Possible control to individual rows
Possible to use for fertilizer (fertigation)
Possible on slopes
Installation is relatively expensive
Clean water required
Blocking with algae, minerals, salts, bacteria
Cannot be used as frost protection
Flood irrigation
cheap to instal and maintain
Not so efficient
Channel irrigation
Similar as flood but the water flows in furrows between vine
more effective
Overhead sprinklers
Expensive to instal and maintain (high pressure) but can be used against frost (but not so water efficient)
Regulated deficit irrigation (RDI)
System of timing and regulating the amount of irrigation so the wine is put under mild to moderate water stress for a specified time within growing season.
Reduces size of berries, better quality, lower yield
Canopy management
Explanation and aims
Organisation of shoots, leaves and gruit of the vine in order to maximase grape yield and quality
Maximise light interception
Reduce shade within the canopy
Ensure that the microclimate for the grapes is as uniform as possible (even ripening)
Promote balance between vegetative and reproductive functions
Ease mechanisation or manual labour
Promote air circulation (reduce disease)
Canopy management and quality
Increased sugar levels
Increased tannin levels and greater polymerisation (less bitterness)
Enhanced anthocyanins
Decreased malic acid
Favourable aroma precursors and compounds
Decreased methoxypyraxines (herbaceous character)
Effect of under-cropping
Vigour of the vine continues during the vine cycle because there is not much fruit to ripen. Growing shoots compete with grapes for sugar and nutriens which negatively affects ripening, resulting in lower quality fruit.
Next year will have low yield because of reduced bud fruitfulness. - vegetative cycle
Effect of over-cropping
Vine will source carbohydrates from the trunk, cordons and roots (those which are needed for winter), which weakens the vine in future years
Other influences of vigour of vine
Specific grape varieties
Choice of rootstock
Viruses
Age of vine
Explain yield
Measure of the amount of fruit produced.
Per vine (kg per vine)
Over area (kg per hectare or tons per acre)
Canopy management techniques
Site assessment to determine ideal grape variety rootstock vigour, planting density, row orientation
Vine training
Winter pruning
Vine trellising
Overall plant vigour management (nitrogen fertilization, irrigation, cover cropping)
Summer pruning (Shoot removal, shoot positioning, pinching, shoot trimming, leaf removal, crop thinning/green harvesting)
Vine density
Number of vines that are planted per hectare of vineyard
Influenced by:
Vigour of vine (grape variety, rootstock)
Type of trellising system used
What access is needed between rows
Vines high in vigour need greater within-row spacing to grow and be in balance
Vines grown in dry conditions will need low density so the roots can spread out to search for water
Between-row spacing considered for shading and machinery
Row orientation
Depends on climatic and logistical factors
North-south provides the most evn sunlight exposure (but west side facing grapes need some extra shading from afternoon sun)
Wind has influence (usually 90’ angle)
Slopes greater than 10’ need to be planted up and down the slope to prevent machinery from slipping
What does vine training and trellising depend on
Vine vigour - natural resources (water, temperature, nutrients), planting material (rootstock, clone, variety), and presence of disease (viruses lower vigour)
The site’s topography (many trellising systems cannot be used on slopes)
The need for mechanisation
Vine training
The shape of permanent wood
Cordon - usually spur pruned, takes longer to establish
Head-trained - relatively little permanent wood, spur-pruned or replacement cane-pruned
low trained (to benefit from heat, protection from wind) or high trained (avoid frost, ease labour)
Pruning
Removal of unwanted parts of the vine
Winter pruning determins the number and location of buds that will form fhoots in the coming season
Spur-pruning - short sections of lignified one year old wood that have been cut to only two or three buds
Easier to carry than replacement cane and can be mechanized
Replacement cane-pruning - longer section of one year old wood with between 8 and 20 buds. Typically laid down horizontally and trellised for support. More complex and requires skilled labour
Number of buds depends on vigour (adjusts balance of growing cycle)
Trellising
Permanent structures of posts and wires that help to support and position the vine’s shoots
Untrellised vineyards - head trained spur-pruned (bush wines) Simple, easy and inexpensive. Suitable in hot climates for extra shading. Not suitable for mechanization and wet climates (high vigour with thick canopy, too much shade and risk of diseases)
Trellised vineyards
A) Vertical Shoot Positioning (VSP) - most common type, most simple. Cordon or head trained. Guyot - replacement cane-pruned wines. (Single or Double Guyot) for wine with low or medium vigour.
B) Complex training systems for vigorous vines. Splitting canopy to reduce shade and maximise light exposure. Horizontally (Geneva Double Curtain or Lyre) or vertically (Smart-Dyson or Scott-Henry)
Large yields or high quality fruit
More difficult to mechanize and manage
Summer pruning techniques
Enhancing ripening, reducing risk of fungal diseases etc.
Disbudding - late in spring to adjust number of buds to bring vine in balance and remove poorly positioned buds
Shoot removal - infertile or poorly positioned
Shoot positioning - tucking into trellis
Pinching - (cannot be mechanized) removing shoot tips at flowering to improve fruitset
Shoot trimming - cutting shoots to limit growth and reduce canopy thickness to enhance gruit ripening and reduce competition for carbohydrates
Leaf removal - reducing shading and lowering disease risk
Crop thinning (green harvesting) - to increase ripeness, if timed near veraison it enhances ripening. Removing grapes which are the least developed. Reducing yield to comply with law
Weather related hazards
Drought
Excess of water
Untimely rainfall
Freeze
Frost
Hail
Sunburn
Smoke taint
Drought
Vine needs min of 500mm in cool climate and 750mm in warm regions per year
Water stress pushes the vine to close stomata to limit water loss. This reduces photosynthesis
Unripe grapes, lower yealds
Management options:
Irrigation
Rootstock - V. rupestris and V. berlandieri (110R and 140R)
Drought resistant varieties
Excess of water
Too much vegetative growth - too much shading, less ripeness, fungal diseases
Water logging - reducing amount of oxygen available for roots
Planting on slopes, on free-draining soils, investing in drainage system
Untimely rainfall
During pollination and fruit set can cause millerndage or coulure.
Mid season can reduce rate of ripening of fruit
Around harvest can make the grapes swollen - diluted flavours, splitting, grey rot, difficulty for harvesting
Options: monitoring weather, considering early harvest
Freeze
Temperature below -20 are critical
Grafts are the most in danger
Management options:
Site selection - hillsides rather than valley floors
Moderating influence near water bodies
Vineyards where snow settles most thickly thick layer protects the vine
Resilient varieties such as Riesling and Cabernet Franc
Hybrids for extreme conditions
Hilling up (building soil around graft)
Burrying vines
Vines with several trunks to create space for replacement.
Frost
Cold air collects at ground level, freezing water in the vine’s growing buds and shoots.
Advective frost - caused by large volumes of cold air moving from cold aread
Radiative frosts - result of heat being lost on still cool nights
Reducing risk
Site selection - avoiding frost pockets
Delaying prning postpones budburst into warmer months
Late budding varieties
High trained vines
Bare soil between vines - bare soil collects heat and radiate it back at night
Fighting frost
Water sprinklers - as water freezes around the plant it releases latent heat, protecting plant
Wind machines - pull warm air from above to ground lavel
Oil or propane gar burning heaters or wax candles
Hail
Rockets (seeding clouds with iodide to cause rainfall instead of hail)
Netting (but this also causes shading)
Number of different plots in other areas to reduce risk
Insurance against hail
Sunburn
Grape transpiration is more limited and less effective than transpiration of leaves. Grapes can reach higher temperatures than leaves and become burnt
Leads to scars and splitting, fungal diseases, off flavours, bitter taste
Management options:
Row orientation and aspect
Canopy management to provide shading
Additional irrigation during heatwaves to reduce water stress
Agricultural suncreen spray
Shading with cloth or net
Smoke taint
Smoky or plastic aromas in wine
Increases in period after veraison
Compounds of smoke bind with sugars and are released with fermentation then increase with maturation and ageing in bottle
Management option:
Analysis
Hand harvesting, gentle pressing, lower fermentation temperatures, reduced maceration reduce uptake of these compounds
Flash detente and reverse osmosis can help but not remove it completely
Blending with unaffected grapes to dilute it
Pests
Phylloxera
Nematodes
Grape moths
Spider mites
Birds
Mammals
Phylloxera
Identified in 1863 and destroyed two-thirds of Europe vineyards
Small insect which feeds on and lays eggs on the roots of vines. It weakens vine roots and causes swellings and cracks, which then lead to rot.
It can spread by crawling and flying and is commonly transported by humans on roots of young vines, in soil, on equipment
Symptoms:
Vines die of drought in patches which increase in size each year
Roots are covered with insects surrounded by yellow eggs
Swellings on older roots
Pale green leaf galls on under the surface
Slow stunted shoot growth ad leaf yellowing appears in around 3 years, the plant dies after around 5 years
Management options:
Does not survive on sandy soils
American species such as V. berlandieri, V. riparia, V. rupestris form hard corky layers that surround te eggs, sealing the wounds and preventing invasion by bacteria or fungi
European vines grafted on American rootstocks
American rootstock has low tolerance to lime which lead to creating of hybrids of more species
Nematodes
Tiny worms, very common in soil but too small to be seen by naked eye. Feeding on vine roots, significantly reducing yield and vigour. Transmit viral diseases.
Most common root-knot nematode and dagger nematode
Spread by unclean nursery stock, irrigation, vehicles. Once present, they can only be managed not eliminated
Management options:
Soil analysis in laboratory
Leaving the soil fallow for number of years
Fumigate soil
Plough in a cover crop of mustard plant which works as biofumigant, killing nematodes
Nematode-resistant rootstock
Grape moths
Feeding on flowers and grapes. Many species have several generations per season
The wounds created are vulnerable to further attack from bacteria and fungi including botrytis
Light brown apple moth (Australia)
European grapevine moth
Grape berry moth
Management options:
Introduction of bacteria Bacillus thuringiensis which produces substance that is toxic to moths
Use of pheromone capsules to disrupt mating
Natural predators (parasitic wasps, green lacewings, some spider species)
Insecticides
Spider mites
Pacific spider mite (California)
Red Spider mite and yellow spider mite (Europe)
feed on surface sells of leaves, which leads to discoloration of leaves and reduction in photosynthesis, delayed ripening, reduction in yields.
They thrive in dusty conditions
Management option:
Use of sprinklers, cover crops, mulches to reduce dust
Encourage predatory mites
Pesticides
Birds
Physical damage to grapes and threat of bacteria and fungi which can lead to rot
Netting
Bird scarers and noises
Falcons
Fungal diseases
Powdery mildew
Downy mildew
Grey rot
Eutypa dieback
Phomopsis cane and leaf spot
Esca
Powdery mildew
Introduced in Europe in mid 1800.
Caused by fungus Erysiphe necator (Oidium tuckeri) American species are less vulnerable
Common for Chardonnay and Cabernet Sauvignon (Pinot Noir and Riesling are less prone)
Overwinters in buds and on canes. Then attacks young green parts of vine, which starts with dull grey patches and become black patches. Reducing yield. Grapes can laso split at veraison and become target for other infections
Optimum temperatures are around 25 degrees and shade. Does not require high humidity so can spread in dry conditions as well.
Management options:
Keeping open canopy
Application of sulfur
Fungicides (but fungus can become resistant)
Downy mildew
Caused by Peronospora, a water mould that lives within vine tissue not on the surface. Introduced from America in late 1800
Attacks especially young green parts and reduces yield by defoliating
Needs rainfall and warm temperatures around 20 degrees
Yellow circular oil spots and then white downy fungal growth on the underside of leaves
Management options:
Bordeaux mixture (sopper sulfate and lime)
Other fungicides
Good drainage and open canopy
Grey rot
Botrytis cinera, loss of yield and quality.
Affcted fruit should be selected out at harvest.
Grapes are vulnerable if there is any point of entry
The most susceptible are tight bunch varieties such as Semillon, Sauvignon Blanc, Pinot Noir
Managing options:
Selecting varieties with small grapes and thick skins
Keeping open canopy and removing leaves around bunches
Traditonal sulfur and copper sprays are ineffective
Other fungicides (but develops resistance)
Antagonistic bacteria - Bacillus subtilis
Eutypa dieback
Dead arm
Fungal trunk disease that leads to rotten wood and can affect whole vineyards. Kills vines over 10 years.
Spores are spread by wind. Infection occures through pruning wounds especially during rain.
Most susceptible varieties: Grenache, Cabernet Sauvignon, Sauvignon Blanc
Management options:
Puning late and applying fungicide to pruning wounds
Affected trunk can be cut back 5-10cm beyond visible symptoms and treated with fungicide. Dead wood must be burt
Biological control - Bacillus subtilis
If the trunk is badly affected the options are to retrain from sucker (sprout at the base of the trunk) or replanting.
Phomopsis cane and leaf spot
Infected canes whiten and break off easily.
Grenache is very susceptible
Management options:
Fungicides
Diseased wood should be burnt
Pruning early or late and not in rainy weather
Esca
Complex fungal disease caused by group of oranisms prevalent in warmer and drier climates.
Enters the vine through pruning wounds. Symptoms are tiger-striping of leaves and spotting inside the wood.
Reduces yield and leads to death within few years
Management options:
No chemical control
Prevention - disease-free stock, not pruning in the rain, desinfecting pruning wounds.
Bacterial and virus diseases
Bacterial diseases
Pierce’s disease
Grapevine yellows
Viruse diseases
Fanleaf virus
Leafroll virus
Pierce’s disease
Originated in America
Spread by sharpshooter insect
Quickly kills vines. Lives in sap channels of vines which it clogs, leaging to shrivelling and dropping leaves and death within one to five years
Chardonnay and Pinot Noir especially vulnerable
Management options:
No chemical control
Reducing number of vectors
Introducing predators - wasps
Strict quarantine rules
Developing Pierce's disease resistant vines
Grapevine yellow
Group of diseases spread by vectors (leafhoppers) and untreated stock from nurseries.
Symptoms: delayed budburst, drooping posture because new shoots fail to become woody, canopy turning yellow or red (in black varieties).
Can live in cover crops as well
Chardonnay and Riesling the most vulnerable
Reduced yields and lower quality (high acidity and low sugar)
Management options:
No control
Controlling vector
Best practise in nursery
Fanleaf virus
Group of diseases.
Early leaf growth is stunted canes grow in distorted ways and leaves are very pale and malformed.
Caused by dagger nematode
Cabernet Sauvignon most suceptible
Management options:
No cure, affected vines have to be removed and soil tested
Leafroll virus
Group of diseases
Does not kill vines but reduses yield and quality (high acidity, less colour and lower sugar)
Slows down growth of shoots and roots.
Management options:
Vines have to be tested in lab
No cure - removing unproductive vines
Open canopies to reduce pest
Measurig ripeness before harvest
Sugar levels - handheld refractometer (harvested between 19 and 25 Brix which converts to 11-15% abv)
Aroma and tannin ripeness - determined by taste
Titration can be used to calculate acid levels
pH of the juice
Machine harvesting
Quality can be raised by:
Selecting undesirable fruit by hand before machine harvesting
Optical sorting devices and cruishing system with SO2 already on the harvester
Sorting at arrival to winery
Advantages:
Faster and cheaper
Avoids issues with availability of workers
Can be harvested in night - preventing microbial spoilage and oxidation
Saves cost of refrigeration
Timing of the harvest is flexible
Disadvantages:
Less gentle (some juice is released and berries crushed)
Not economic for small scale
Not suitable on slopes
Competition for rental of harvester in the best time to pick
Substantial initial investment in harvester
Hand harvesting
Advantages:
Pickers can be highly selective
Possible on steep slopes, irregular rows and mixed plantings
Crushing grapes is avoided if handled gently
Disadvantages:
More expensive
Carried in day light - risk of microbial spoilage and oxidation
Labour availability
Not suitable for whole bunch fermentation and sparkling wine or botrytised wine
