Ch 6 - Vineyard Management

Question 1

What is vine training?

Answer 1

Typically refers to the shape of the permanent wood of the vine. 2 categories: head training or cordon training. Either can be low-trained to benefit from heat retained by soil or high trained to avoid frost.

Question 2

What is low training used for?

Answer 2

To benefit from heat retained by the soil.

Question 3

What is high training used for?

Answer 3

To avoid frosts.

Question 4

What is head training?

Answer 4

Vines that have relatively little permanent wood - some only have a trunk and some have short arms growing from top of the trunk. Can be spur pruned or replacement cane pruned.

Question 5

What is cordon training?

Answer 5

Typically vines have a trunk with one or more permanent horizontal arms or cordons. Usually spur pruned. Takes longer to establish because of greater amount of permanent wood but sturdy permanent cordon with shoots positioned along its length makes mechanisation in vineyard like machine harvesting easier. Vines usually have 1 or 2 cordons but cordon trellising can be used to create big vine structures where shoots may grow from four or more cordons.

Question 6

Why is pruning undertaken?

Answer 6

Removes unwanted leaves, canes and permanent wood. Shapes vine and limits size. Also aides canopy management. Takes place every winter and summer.

Question 7

When is pruning particularly important and why?

Answer 7

Important in winter to determine number and location of the buds that will form shoots in the growing season. Important to make sure they aren’t close together. Helps with canopy management.

Question 8

What are they types of winter pruning?

Answer 8

2 types of winter pruning: spur and replacement cane.

Question 9

What is Spur pruning?

Answer 9

Spurs are short sections of 1 year old wood that have been cut down to two or three buds. They are either distributed along a cordon of permanent wood (cordon training) or around top or the trunk (head training).

Question 10

What is replacement cane pruning?

Answer 10

Canes are longer sections of 1 year old wood - can have between 8 and 20 buds. Typically only 1 or 2 canes are retain and each is tied horizontally to the trellis for support. Mostly seen on head-trained vines. More complex than spur and requires large skilled labour force to choose suitable canes and train them. Aka guyot. One can is Single Guyot, 2 is Double.

Question 11

What is Summer pruning used for?

Answer 11

Trimming the canopy to restrict vegetative growth and direct sugar production to the grape rather than the growth of shoots and leaves. Can involve leaf stripping to optimise grape exposure to sun.

Question 12

What are untrellised vineyards and what regions are they best suited to? Why is it not suited to other regions?

Answer 12

Shoots hang down often as far as the ground aka bush vines. Typically head trained and spur pruned. Best in warm or hot, dry, sunny regions e.g. Southern Rhone and Barossa where extra shade helps protect the grapes. In cool or wet regions this shade can impede ripening and lack of airflow can promote disease. Not suited to mechanical harvesting.

Question 13

What is Gobelet?

Answer 13

Like bush vines but the shoots of head-trained, spur pruned vines are tied together instead of allowed to fall to ground which helps expose the bunches to air and sunlight.

Question 14

How does trellising work?

Answer 14

Each row of vines has a line of posts joined by horizontal wires - the canes and shoots are tied to the trellis aka canopy management.

Question 15

Why might a vineyard use trellising?

Answer 15

The arrangement of young shoots can control amount of sunlight that gets into the canopy. IN regions with less light, keeping shoots apart opens the canopy to maximise exposure and aide ripening. IN those with intense light, keeping grapes shaded may reduce sunburn which could lead to off-flavours.

Open canopy can improve air circulation, important in wet climates because damp stagnant air can promote fungal diseases.

Finally, can aid mechanisation by positioning grapes in one area of the vines and leaves in another. Spraying of insecticides and fungicides is also more effective.

Question 16

What is the most widely used canopy management system and how does it work?

Answer 16

Vertical Shoot Positioning (VSP) - can be used with replacement cane or spur pruned vines. Shoots are trained vertically and tied in place onto the trellis forming a single narrow canopy. Keeping shoots apart keeps the canopy open, well aerated and as shade free as possible. In hot regions with lots of sun, VSP can be adapted so the tops of shoots aren’t tied, but flop over to create some shade and protect the fruit.

Question 17

Why might a producer choose VSP rather than untrellised bush vine?

Answer 17

Because mechanical harvesting can be used with VSP.

Question 18

What might a grower do if the vineyard has limited water availability?

Answer 18

Limited water availability - areas with little water may benefit from low density so each roots can take up water from large volume of soil without competing against neighbouring vines.

Question 19

What factors may impact the choice regarding yields in the vineyard? How are yields managed and measured?

Answer 19

Yields - there may be legal requirements limiting or proscribing yields. May have contractual obligations to winemaker. May predict yields from the number of buds left on vine after winter pruning but frost, poor fruit set, pests etc could reduce this. If yields are too high then can remove immature grapes shortly after veraison - aka green harvesting but this is risky because if done at the wrong time the vine will compensate by increasing size of the grapes left. Can dilute flavours in remaining grapes.

Question 20

What might a grower do if the vineyard sees sufficient rainfall and has high nutrient content?

Answer 20

Many New World regions in particular offer the vine more nutrients than classic European regions - high density planting is not enough to limit the growth of vines so they use low density planting using vines with multiple cordons or canes. Often can produce good quality grapes at high yields - common in NZ.

Question 21

What might a grower do if the vineyard sees sufficient rainfall and has low nutrient content?

Answer 21

Provided the vine has access to sufficient water it can thrive even in barely fertile soil. Left unchecked it could produce too much vegetation so vines should be planted at high density to provide competition for resources and restrict vegetative growth. Also important to ensure the vine has correct number of buds after winter pruning because if there are too few each will have access to too much energy - iff there are too many though they won’t get enough energy to ripen. If managed correctly, the combination of density and pruning makes open canopy easier to maintain with advantages it confers on fruit quality and disease control. Very common in many European Vineyards.

Question 22

What are the main pests in vineyards? Describe how each may impact vines. What can be done to avoid/control each?

Answer 22

Phylloxera - attacks the foots underground and infects the vine which slowly weakens and dies. Use of american rootstocks which are resistant to phylloxera is common.

Nematodes - microscopic worms that attack roots of vines interfering with nutrient and water uptake. Can give viruses. Sanitising soil before replanting and using resistant rootstocks are helpful.

Birds and mammals - both consume grapes and half eaten ones can increase risk of fungal dsieas. Netting best option against birds - fencing against mammals like rabbits.

Insects - feed on grapes and leaves. May use insecticides or integrated pest management.

Question 23

Describe downy and powdery mildew and their impact on the grapes.

Answer 23

Downy and powdery mildew - thrive in warm, humid environments and can affect all of the green parts of the vine including leaves and grapes. Causes loss of fruity flavours and can give mouldy, bitter taint.

Question 24

Describe grey rot and its impact on grapes.

Answer 24

Caused by Botrytis cinerea and thrives in damp conditions. Attacks grapes and can taint flavours and lead to loss in colour of black grapes. For some white grapes this rot is good and can help produce sweet wines (noble rot).

Question 25

How can the risks of fungal disease be controlled?

Answer 25

Powdery mildew was traditional treated with a sulfur-based spray, downy with bordeaux mixture (copper-based). Now other chemicals also exist. Spraying required more in maritime climates because of high rainfall during growing season.

Appropriate canopy management can also help. Dense shady vine canopy restricts airflow and prevents water from evaporation - creates humid environment which encourages disease. Open vine canopy allow sair flow and promotes evaporation. Also reduces use of chemical sprays which can be a financial and environmental advantage.

Question 26

How can viruses be spread and what is their effect on vines? How are they treated?

Answer 26

Mostly don’t kill the vine but limit its ability to function and reduces yield and quality. Can be spread by cuttings or nematodes. They can’t be cured or treated - have to dig up vines and sanitise the land.

Question 27

How can bacterial diseases be spread and what is their effect on vines? How are they treated?

Answer 27

Sharpshooters - small insects. No treatments. Quarantine procedures and interrupting lifecycle of the sharpshooters are the ways of preventing these. Once vine is infected the only way to deal with it is to dig up vines and sanitise land.

Question 28

What are the characteristics of sustainable agriculture? Include description of integrated pest management.

Answer 28

Man made chemicals not prohibited but use restricted. Growers encouraged to develop understanding of vineyard pests and monitor weather so they can predict and prevent pests or outbreaks of disease before they occur. This reduces spraying as they do not just do it on a calendar basis.

Integrated pest management is key - predators of some pests may be encouraged to live in the vineyard to control populations naturally. Supporting a range of plants in vineyard can provide habitats for predators and nutrients for vines when they’re mowed or ploughed.

Question 29

What are the characteristics of organic agriculture?

Answer 29

Similar to sustainable but only a few limited traditional treatments are allowed in very small quantities. Accreditation is required from an organic certification body if the producer wants to put it on the label. Each organisation may have slightly different standards. All require a period of conversion working towards organic standards before certification.

Question 30

What are the characteristics of biodynamic agriculture?

Answer 30

Based on work of Rudolf Steiner and Maria Thun. Organic practices with philosophy and cosmology as well. Vineyard soil seen as part of a connected system with planet earth, the air and other planets. Growers adapt practices to coincide with cycles of the plants, moon and stars. Homeopathic remedies are used to fertilise and treat diseases and ward off pests. There are certification bodies too.

Question 31

What is Véraison?

Answer 31

The point at which grapes begin to ripen. Signalled by change in colour of their skins.

Question 32

What happens to sugar and acid levels as grapes ripen?

Answer 32

Sugar rise and acid drops.

Question 33

How can growers track ripening?

Answer 33

By monitoring the rise in sugar levels.

Question 34

When do grape develop their signature flavours and what happens to the tannins at this stage?

Answer 34

Develop during ripening - tannins in the skins become less bitter and astringent.

Question 35

When will harvest occur?

Answer 35

Depends - when the winemaker and grower feel the grapes have the right qualities for the desired wine - this will mean balancing sugar, acid, flavour and tannin. However, can be determined by weather - might bring forward to save the crop if they expect hail or rain. Also need to coordinate with the winery to ensure they have capacity.

Question 36

Why might a vineyard opt for machine harvesting?

Answer 36

May be cheaper depending on cost and availability of labour. May also require the speed if a vintage is threatened by bad weather or for some varieties like SB which can ripen suddenly and become over-ripe quickly. Machines can work through the night - so may opt for them if need cool grapes to be brought in. Saves money and energy lowering temperature before fermentation and slows down oxidation (which leads to off flavours).

Question 37

Why might a vineyard opt for hand harvesting?

Answer 37

Allows grape selection to take place in vineyard rather than with later sorting. Unripe grapes can be left on the vine for further ripening. If using noble rot grapes they have to be handpicked because onset and level of rot varies between bunches and within a bunch. Less damage occurs when hand harvested. Stems are retained so get whole, intact grape bunches that can produce very clean, pure juice when pressed in white winemaking and are essential for whole bunch fermentation in red. May be only option on steep slopes like in Mosel, Duoro and Northern Rhone.