What are the 2 main species of vine?
1. Vitis vinifera
2. North American Vines (3 chief species):
- Vitis labrusca
- Vitis riparia
- Vitis rupestris
What is phylloxera?
- A fungal disease
- A viral disease
- A North American root louse
A North American root louse.
Of the two main vine species, which one is more resistant to phylloxera?
How does it protect itself?
North American vine species are more resistant to phylloxera. It is for this reason American rootstocks are widely used across the world.
The North American vine protects itself from phylloxera by seeping a sticky sap that inhibits the louse from eating, and the vine generates a defensive layer behind a wound which prevents the louse from damaging the plant material further.
Are there any places in the world today that remain free of phylloxera?
Yes, the major ones are:
- Some areas in South Australia and Argentina
Of the two main vine species, which is the most widely used around the world for quality wine production?
Vitis vinifera is most used for fine wine grape growing in the world.
The grape varieties we all know by name are from the Vitis vinifera family, such as Sauvignon Blanc, Chardonnay, Pinot Noir, Zinfandel, Syrah, and Cabernet Sauvignon.
What are some primary differences between Vitis vinifera and North American vines?
- known to have more desirable aromas for wine
- considered to produce higher-quality grapes for the production of fine wine
North American vines:
- more resistant to pests and diseases than vinifera
- generally better suited to extreme climates than vinifera
What are 2 different ways a vine can be propagated?
Cutting - when a section of a shoot is cut off from an existing vine and is planted in order to grow a brand new plant. It's done mostly in nurseries;
Layering: A vine's 1 year-old cane is bent into the ground and partially buried with the tip of the cane poking out above ground; the buried part grows roots and establishes itself as a new plant. It takes place in the vineyard.
What is clonal selection?
When a vine naturally mutates and its new, positive characteristics are propogated by cutting or layering.
Grafting is a procedure used to fuse budwood of a desired variety (usually V. vinifera) onto another rootstock (usually a North American vine).
This technique was discovered to be both useful and necessary after phylloxera decimated European vineyards in the mid-to-late 1800s. The idea is to have a phylloxera-resistant vine that produces V. vinifera.
What are some of the benefits of grafting onto American rootstocks?
- American rootstock protects against phylloxera while giving ability to produce V. vinifera grapes;
- North American rootstocks are found to be resistant to nematodes, drought, and alkaline soils, unlike V. vinifera.
What is head grafting and why is it used?
Head grafting is when a vine's top, or head, is cut off its trunk and the cutting of a new variety is grafted on to the trunk where the old head was.
The purpose of head grafting is to switch out grape varieties instead of uprooting and replanting an entire vineyard. Head grafting will produce fruit the year after the grafting, and it's a lot less expensive than replanting an entire vineyard with the added bonus of keeping the established trunk and roots.
How are new grape varieties created?
What is cross-fertilization?
Name a few reasons why a viticulturist might want to cross-fertilize.
Cross-fertilization is when a viticulturist takes the pollen from the male part of one vine's flowers and fertilizes the female parts of a different vine's flowers to create a new grape variety.
The cross-fertilized flowers will grow into grapes, which will have seeds. Those seeds are collected, later planted, and if those seeds grow into a viable plant, a new grape variety is born.
Reasons to cross-fertilize:
- To create a disease resistant variety;
- To adapt the new grape to climate extremes or drought;
- To increase quality or yields.
What is the difference between crossings and hybrids?
Crossings: when a new grape variety is created by crossing parents of the same vine species, e.g. Cabernet Sauvignon (Sauvignon Blanc x Cabernet Franc - both V. vinifera).
Hybrids: when at least two different vine species, usually a North American vine and a vinifera vine, are crossed to create a brand new vine species, e.g. Concord and Vidal Blanc (only 1 parent is V. vinifera).
What is the crossing of Cabernet Sauvignon?
Cabernet Franc x Sauvignon Blanc
What is the crossing of Müller-Thurgau?
Riesling x Madeleine Royale
What is the crossing of Pinotage?
Cinsault x Pinot Noir
What are the 4 main parts of a vine?
- Permanent wood
- 1 year-old wood
- Green parts (also known as the canopy: leaves, grapes, tendrils, etc.)
Explain the importance of a vine's leaves.
Leaves are what drive the plant's growth.
Via photosynthesis, leaves use sunshine to convert water and CO2 into the things it needs to grow: glucose and oxygen.
What is transpiration?
Transpiration is the process of how water is absorbed by a vine's roots, transported throughout the plant, and out of its leaves in vapor form.
The warmer the climate, the faster water evaporates from the leaves, which means the vine needs more water from the soil.
To get really nerdy, read more about transpiration here.
What are tendrils on a vine and what is their role?
Tendrils are a vine's support system so that it stays upright (or attached to a trellising system).
What are the buds on a vine?
Where are they found?
Buds contain and will become the following year's green parts (tendrils, flowers, leaves, shoot).
Buds are primordial shoots found between a shoot and a leaf.
What is 1-year-old wood (aka a cane)?
The previous year's shoot
The buds on last year's shoot will be the 1-year-old wood's shoots, tendrils, and leaves.
What is permanent wood on a vine?
Wood that is more than 1 year old:
- arms / cordons (if there)
What are the functions of a vine's roots?
Absorb water + nutrients which they send up the plant
Anchor the vine in the soil
Store carbohydrates over winter to keep the vine alive
What are the "reproductive organs" of a vine?
Flowers have both male and female parts, and vines' flowers self-pollinate. Each pollinated flower then turns into a grape.
What is inflorescence?
Clusters of flowers (before they actually become flowers).
Inflorescences will eventually become flowers which then transform into grape clusters.
Photo courtesy of Patty Skinkis, Oregon State University.
What is the difference between a cane and spur?
They're both 1 year-old wood from the previous year's growth. However, the main difference between them is how many buds each has.
Cane: a long woody branch with 8 to 20 buds
Spur: a short woody branch with only 2 to 3 buds
What are some important factors to consider when deciding where to establish a new vineyard?
1. Environmental/Climate considerations
- location and aspect of proposed vineyard
- soil type/fertility, drainage, average sunlight/rain, temperature
2. Trade/Business considerations
- how remote is the vineyard?
- how easy will it be to find employees or help at harvest?
3. Which grape(s) to plant?
- which varieties suit the climate?
- is there demand for the grape(s)?
- any legal restrictions?
What are the 2 main types of vine training?
Describe head training.
Usually just a trunk (not a lot of other permanent wood)
- Can have just a couple of spurs or replacement canes, no permanent "arms"
Describe cordon training.
- More permanent wood than head trained;
- A trunk with usually one or two permanent arms or "cordons";
Usually spur-pruned (spurs look like "fingers" growing out of the arm/cordon, see photo);
- Mechanized harvesting easier.
The removal of undesirable canes, leaves, and permanent wood.
When are vines pruned?
What are the purposes of summer pruning?
- Control the canopy, which...
- Forces sugar production in the grape instead of the vine directing that energy to expand the canopy;
- Give grapes favorable sun exposure via leaf stripping.
In regions with powerful sunlight, what risk is there if the canopy is deleafed too much during summer pruning and exposing the grapes to that intense sunlight?
Sun burn, which will lead to off-flavors
What are the purposes of winter pruning?
- To chose the number + location of buds that will form shoots in the upcoming growing season;
- Ensure buds are not too close to each other (this helps with next year's canopy management).
What are the 2 styles of winter pruning?
- Replacement cane
Spur pruning can be found on what type of vine training?:
- Head trained
- Cordon trained
- Both head and cordon trained
Both head and cordon trained
Replacement cane pruning is most often found on what type of vine training?:
- Head trained
- Cordon trained
- Both head and cordon trained
What are trellises, or a trellising system?
A system of permanent stakes (wood or metal) with wires that support the vine for its annual and seasonal growth.
The wires can also support canes and cordons.
3 reasons to use a trellising system instead of Bush vines:
Control the amount of sunlight that gets into the canopy;
Improve air circulation for the leaves and grapes;
- Positioning grapes and leaves improve mechanical harvesting + distribution of any sprays used.
Give 2 examples of head-trained vines.
Bush vines tend to produce a lush canopy, so they perform best in hot, dry regions such as Jérèz or Southern Rhône where the grapes need the extra shade.
Bush vines are generally head-trained and spur-pruned (meaning, 2-4 buds on each 1 year-old spur).
Guyot vines are generally head-trained and cane-pruned (meaning, a permanent main trunk with 1 cane + a spur [Single Guyot) or 2 canes + spurs [Double Guyot]).
See this article by Caroline Gilby, MW for further explanation on Guyot and Gobelet.
What is a synonym for Bush vines?
Gobelet -- so called as it is resembles the shape of a wine glass or goblet.
Bush/Gobelet vines are untrellised.
When using replacement cane pruning, if the vine has 1 cane it's called __ Guyot; if it has 2 canes it's called __ Guyot.
1 cane = Single Guyot
2 canes = Double Guyot
What is the most widely used trellising system?
Vertical Shoot Positioning, or VSP
Describe Vertical Shoot Positioning (VSP).
How is it beneficial?
Which pruning styles is it compatible with?
1. VSP is where shoots are positioned in an upward direction attached to the trellis wires, creating a single-layered, narrow canopy.
VSP allows for good air circulation and the grapes to be exposed to direct sunlight (less shade).
Compatible with both replacement cane pruning and spur-pruning.
What pruning can VSP be used with?
Cane- or spur-pruned vines
VSP is conducive to which type of harvesting: mechanical or hand?
Define planting density.
The number of vines planted within a determined area.
How is planting density typically conveyed?
Number of vines per hectare
e.g. The average planting denisty for Burgundy is 8,000-10,000 vines per hectare.
How big is a hectare?
A square stretch of land that has 100-meter sides
1 acre is approximately how many hectares?
1 acre = .4 hectares (or 0,4ha)
Conversely, 1 hectare = 2.47 acres
What are 2 big factors that help a grape grower determine a vineyard's planting density?
If a region has limited water availability (low rainfall, limited access to irrigation), would it make sense that a vineyard's planting density be higher or lower?
Lower because it would decrease the vines' competition with each other and other vegetation for water and nutrients.
If a region has good water availability + soil with just-enough nutrients, would it make sense that a vineyard's planting density be higher or lower?
Higher because with all that water available vines will produce a profuse canopy.
Higher density planting increases competition which will curb the vines' tendency to put all their energy into the canopy.
This is where winter pruning comes in: did the grower leave the proper number of buds from last year's growth to control canopy and fruit development this year?
Which soil is more desirable for viticulture:
- barely fertile
- very fertile
It's counter-intuitive, but barely-fertile soils are better for grapevines: stressed vines make good wines.
Very fertile soils make vines grow like crazy and a challenge to manage, even with super-high density plantings (it can be done, though).
What does yield measure?
How is yield expressed?
Yield measures the quantity of grapes produced, in weight or volume.
Expressed by weight: tonnes per hectare
Expressed by volume: hectoliters per hectare
Véraison is the onset of ripening and when the grapes change color.
- Red varieties turn from green to purple or black;
- White varieties go from green to translucent-pink and gold.
What happens to grapes during berry ripening?
- Sugars increase;
- Acidity levels decrease;
- Tannins develop and become less astringent.
What is green harvesting and when is it done?
Why is it done?
Dropping underdeveloped grape clusters right after véraison. Viticulturists will literally walk their vineyards and cut off immature grape clusters, leaving them on the ground.
It can be done for a few reasons, but for this exam know that it's done if it looks like yields are going to be too high.
How does the vine react if green harvesting is done at the wrong time?
The vine will increase the size of berries on the remaining clusters, which can dilute flavors and increase yield (in weight and/or volume).
Name some vineyard pests other than phylloxera.
- Deer (and other mammals)
What are nematodes, and what damage can they cause to a vine?
Nematodes are microscopic worms that eat the roots of vines, leaving open wounds through which viruses are known to enter.
Affected vines must be removed, they cannot be grafted.
What protections for their vines can a grape grower utilize against birds and mammals?
Netting for birds
Fencing for mammals
What damage can insects cause to vines?
They can eat through leaves and grapes, the latter of which can invite rot and disease.
Leaf damage slows photosynthesis, which directly affects a vine's ability to ripen its grapes.
What are the 3 types of diseases that affect vines?
Name 3 fungal diseases.
- Downy mildew
- Powdery mildew
- Grey Rot
How do Downy or Powdery Mildew affect vines and their grapes?
What is the typical fungicide treatment for Powdery Mildew?
What is the typical fungicide treatment for Downy Mildew?
Bordeaux mixture, a copper-based spray
In what climate will you find more fungicide treatments used?
High rainfall and generally more humid air encourage fungi.
How are fungal diseases controlled?
What are the treatments or cures for viral diseases?
There are none.
The only way to get rid of a viral disease is to uproot the vine and sanitize the land.
How do viruses spread in vines?
How do viruses affect vines?
Can they kill the vine?
- Reduce grape quality
- Reduce yield
Most viral disease do not kill the vine.
What is the fungus that causes grey rot?
Botrytis cinerea is the fungus that causes grey rot.
Which one develops - the beneficial Botrytis or the bad grey rot - really depends on the weather. If afternoons become sunny and warm, dissipating humidty and moisture in the air, Botrytis (Noble Rot) develops. However, if afternoons remain grey and soggy, grey rot takes hold and truly just rots the grapes.
How do bacterial diseases affect vines?
Can bacterial diseases kill a vine?
- Reduce grape quality
- Reduce yield
Some bacterial diseases can kill a vine.
How do bacterial diseases spread in vines?
Insects called sharpshooters spread bacterial diseases
What are the treatments or cures for bacterial diseases?
There are none.
If a vine becomes infected with a bacterial disease, the vine must be uprooted and the land sanitized.
If the vine was bacterially infected by a sharpshooter, a viticulturist can try to disrupt the insect's lifecycle with quarantine and other methods, but it's very difficult.
Describe sustainable agriculture.
use of synthetic chemicals is restricted but not prohibited;
- spraying or applying chemicals only when needed;
- practicing Integrated Pest Management - introducing natural predators to control pests;
create biodiversity in the vineyard.
Describe organic viticulture.
synthetic chemicals not allowed;
- the only real chemicals allowed are sulfur and copper, and their applications are restricted;
- if a winery wants to be certified organic, they must apply for accreditation with one of the certifying bodies and work their vineyard organically for at least 2 or more years prior to certification.
Describe biodynamic agriculture.
- Biodynamics is much more than a method, it is a spiritual science, a belief system — a holistic way of seeing and understanding the natural world that focuses on regenerative practices.
- Biodynamics sees the vineyard as an ecological whole: not just rows of grapevines, but the soil beneath them—an organism in its own right—and the other flora and fauna in the area, growing together interdependently.
- Where biodynamics differs from organic or sustainable agriculture is in its idea that farming can be attuned to the spiritual forces of the cosmos. This might mean linking sowing and harvesting to the phases of the moon or the positions of the planets.
Who are seen as the father and mother of biodynamics?
Rudolf Steiner, an Austrian philosopher, writer, social reformer, and esotericist. 1861-1925.
Maria Thun, a German researcher, farmer, and Steiner devotee. It is from her astronomy observations that we get today's root, leaf, fruit, and flower days. 1922-2012.
What are the homeopathic remedies called in biodynamics used to fertilize soil and protect vines?
Read more about biodynamic preparations here.
What are the top three most important nutrients for vines?
These nutrients are naturally present in soil.
What is chlorosis?
Chlorosis is a nutrient deficiency in the soil that affects the vine's ability to photosynthesize. A sign of chlorosis is yellow leaves and poor overall growth.
The usual cause for chlorosis is a lack of iron in the soil. Farmers will either add iron-rich fertilizers or plant iron-producing grasses as cover crops to treat the soil.
After winter, when temperatures rise above 10°C (50°F) is when vines start ___.
When the temperature drops below 10°C is when vines go ___.
Above 10°C: Budburst
Below 10°C: Dormant
List a vine's annual cycle.
Budburst: early spring
First shoot/leaf growth: spring
Flowering: late spring/early summer
Fruit set: early summer
Ripening: summer/late summer
Harvest: late summer/early autumn
When does budburst happen in each hemisphere?
What happens during budburst?
- March-April (early spring): northern hemisphere
- Sept-Oct (early spring): southern hemisphere
- new growth starts emerging from buds
During what months does flowering occur in the northern and southern hemispheres?
- Northern hemisphere: May/June
- Southern hemisphere: November/December
What is the optimal weather during flowering?
Warm temperatures, plenty of sunshine, little or no rain.
Frost is most dangerous around which phase of the vine's annual cycle?
What are some adverse effects from frost?
Budburst is when frost is most dangerous (March/April in Northern Hempishere, Sept/Oct in Southern Hemisphere).
- if frost occurs right before budburst, it can delay budburst which means the grapes are at risk of not fully ripening before autumn;
- new plant material can freeze and die;
- spring frost damage can decrease the annual yield;
- fungal diseases can develop if the weather stays wet.
What is coulure?
Coulure is poor flower set due to poor fertilzation in cold or rainy conditions.
Fun Fact: the flowers that drop from the cluster are known as "shatter."
What is millerandage?
The term for poor or irregular fruit set (some grapes forming without seeds and/or remaining small) due to cold, cloudy, or rainy conditions during pollination.
Fun fact: it produces clusters with "hens and chicks," or big and small grapes. See image.
What vineyard work is done while the vine is dormant?
The vinegrower removes the previous year's shoots and cane(s) to establish next year's growth.
What detrimental effect can drought have on a vine?
- vines may stop transpiration + photosynthesis;
- leaves wilt, causing grapes not to ripen;
- drought can kill a vine.
What are the effects on a vine if its roots are generally around too much water (read: poor drainage, waterlogging, etc.)?
If a vine's roots become waterlogged or have excessive water available to it, a few things can happen:
- canopy overgrowth, which takes energy away from grapes so they won't ripen properly;
- bloated grapes, which dilutes flavors;
- roots can rot.
What sorts of damage can rainfall cause before, during, and after berry development?
- Before: disturb flowering and fruit set;
- During: encourage the development of fungal diseases;
- After: if right before harvest, rain can bloat berries, dilute their juice, and introduce grey rot.
What are the 3 most important irrigation systems used around the world?
1. Drip irrigation
2. Sprinklers (can also be used for frost protection)
3. Flood irrigation
Between clay, sand, and stone, which soil has the highest water retention?
Clay has the highest water retention capability of the three.
Clay also has the smallest soil particles.
Sand and stony soils drain easily.
Besides clay, what soil element is known for good water retention?
Humus, which is organic matter made up of decomposing plant and animal materials.
What is the composition of loam soil?
Loam is a mixture of sand and clay. It has both good water drainage and retention due to its composition.
How many years after first planting a new vineyard will vines produce a usable crop?
The third year after planting.
How often is a vineyard typically replanted?
About every 30 to 50 years.
After 25-30 years, a vine produces less quantity but higher quality crops.
Is it common practice to leave a vineyard fallow for a few years after its vines have been uprooted?
Yes, it's common to leave a vineyard fallow for at least 3 years prior to replanting. This time off allows the farmer to work the soil and help it regain its nutrients so it can accept new plantings.
What are the advantages of mechanical harvesting?
efficient - berries are shaken from stems so there is no need for a destemmer;
less costly as it decreases number of laborers;
can be done overnight which saves time + costs on lowering grapes' temperatures prior to processing them.
What are the disadvantages for mechanical harvesting?
- not selective;
- can only be used on flat land or gentle slopes;
- not suited for all grapes; best for those that come away easily from their stems.
What are the advantages of hand harvesting?
- easier to control grape quality;
- usually less berry damage, therefore fewer oxidation issues;
- whole clusters are picked which keeps stems intact.
In some places (usually steep and/or with terraces built centuries ago), handpicking is the only option, e.g. Mosel, Valtellina, Northern Rhône.
What are the disadvantages of hand harvesting?
- slow (slower than machine harvesting);
- costlier because more labor intensive
What is the tool used by hand harvesters?
A pair of secateurs (sekəˈtərz), or pruning shears.
What happens in the vine during early shoot + leaf growth?
- Rapid growth;
- vine uses its over-wintered carbohydrates to grow leaves, shoots, and tendrils quickly
- Once leaves mature enough, they take over as the engine to fuel the plant via photosynthesis.
- vine uses its over-wintered carbohydrates to grow leaves, shoots, and tendrils quickly