Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

WSET Level 4 Diploma in Wines | D1 Wine Production > Chapter 8 Hazards, Pests and Diseases > Flashcards

Chapter 8 Hazards, Pests and Diseases Flashcards

You may prefer our related Brainscape-certified flashcards:
WSET ® Level 1 Wine flashcards WSET ® Level 2 Wine flashcards WSET ® Level 3 Wine flashcards WSET ® Level 2 Spirits flashcards WSET ® Level 1 Spirits flashcards Wine Appreciation flashcards Introductory Sommelier Exam (CMS) flashcards WSET ® Level 3 Spirits flashcards WSET® Level 4 Wine flashcards
1
Q

Define Advective frosts

A

Frost caused by a large volume of cold air moving in from very cold places. i.e. cold front

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define Radiative frosts

A

Frost caused by heat being lost on still cool nights. i.e. windless nights allow for a layer of freezing air to collect on the vineyard surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How can a grape grower reduce the risk of frost?

A
  • Site selection: avoid frost pockets and choose hillside sites.
  • Delaying pruning postpones budburst.
  • Choosing a late budding variety.
  • Training vines high off the ground.
  • Having bare soils between vines absorb more heat during the day and radiates the heat during the night.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the options when frost threatens?

A
  • Water sprinklers
  • Wind machines (or helicopters)
  • Oil or propane gas burning heaters (or candles)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the advantages and disadvantages of water sprinklers as an option to frost threats?

A

A
- Spinklers can be used if the vineyard already has an irrigation system and can be put in place.
- The cost of equipment and water are lower than other options (excpect if water is too costly)

D
- The only method that can be used for advective frosts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does water sprinklers work to combat frost threats?

A

Water freezes around the parts of the plant, it releases latent heat and protects the plant. The system must be kept on until the temperature rises.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the advantages and disadvantages of wind machines as an option to frost threats?

A
  • The initial investment is considerable.
  • Effective where there is an inversion layer (warmer air on top on cold air) i.e. radiative frost
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does wind machines work to combat frost threats?

A

Large fans (4 a 7 m) pull warmer air from above down to ground level. Effective if there is warm zone of air 10 m above the ground. (+3-5°C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the advantages and disadvantages of burning heaters as an option to frost threats?

A
  • High cost of fuel and labour
  • Low heating efficiency
  • Contribution to air pollution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define smoke taints

A

The effect that smoke in the vineyard has on the final wine. Can we describe as smoky or plastic aromas.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does smoke taint happens?

A

Aroma compound in smoke can be absorbed by the grapes and bind with sugars and form aromaless precursors. The strength of the aroma can increase during the aging of wine and during bottle aging as further aroma precursors breakdown and become aromatic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the options for smoke taint?

A
  • Affected grape juice can be tested and analyzed.
  • Micro vinifications can be made to understand the extent of the problem and the actions to be taken.
  • Hand harvesting, gentle or whole bunch pressing, lower fermentation temperatures and reduce macerations time can reduce the uptake of the compounds.
  • Flash détente and reverse osmosis can help, but will not remove the taint completely.
  • Blending unaffected wines.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define Phylloxera

A

An insect that feeds and lays eggs on the root of grapevines. It damages the roots, reducing the uptake of nutrients and water, weakening the plant. The roots become vulnerable to bacteria and fungi.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does phylloxera affect the vine?

A
  • Vine roots are covered by the insect and its eggs.
  • Slow, stunted shoot growth and leaf yellowing after 3 years.
  • Death of the plant around 5 years.
  • Swelling on older roots.
  • Pale green leaf galls on the under surface of the leaves
  • Vines die of drought in patches that increase each year.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What can a grape grower do to manage the threats of Phylloxera?

A

Grafting onto rootstock form American vines: V. berlandieri, V. rupestris, V. riparia and hybrids species between American species to balance the level of protection to phylloxera and resistance to lime soil.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What and how rootstocks protect the vine?

A
  • There are many rootstocks suitable for a range of situation: phylloxera, nematodes, extremes of soil ph, water stress, salinity and control the vigour of the vine.
  • Rootstock are expensive but are standard cost of establishing vineyard.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define Nematodes

A

Microscopic worms commons in soils. The most common are root-knot nematode and dagger nematode.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What damages can nematodes do?

A

Some cause damage by feeding off the roots and reducing yields and vigour (slow gradual decline) or transmitting diseases. e.g. fanleaf virus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How can nematodes spread?

A

They can be present in the soil or spread by:
- unclean nursery stock
- irrigation water
- vehicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How can nematodes be managed?

A

Nematodes can only be managed. Not eliminated:
- Fumigate the soil with chemicals (banned in most regions)
- Plant mustard plant as cover crop and plough it into the soil (biofumigants)
- Use nematode resistant rootstocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Define Grape moths

A

A number of different moths (insects) that feed on the flowers and grapes.

The wounds leave the fruit open to bacteria and fungi. e.g. Botrytis -> crop losses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How grape moths are managed?

A
  • The bacterium Bacillus thuringiensis that produces substances that are toxic to moths
  • Use of pheromone capsules to disrupt mating
  • Natural predators (wasp, green lacewings, some spider)
  • Insecticides can be used.
23
Q

Define spider mites

A

Insects that reproduce and live on leaves feeding on them.

24
Q

How can spider mites affect the vine?

A

They feed on the leaves which leads to discoloration on the leaves, a reduction of photosynthesis, delayed ripening and reduction in yields.

25
Q

How can spider mites be managed?

A
  • Use water sprinklers to make the leaves wet.
  • Cover crops or mulches to reduce dust (spider mites thrive un dusty conditions)
  • Encourage predatory mites
  • Use of pesticides or specific sprays. This can be costly.
26
Q

Define Powdery mildew

A

A disease caused by the fungus Erysiphe necator or Oidium tuckeri. It is specific to grape vines and is one of the most widespread. Some varieties are more susceptible than others.

Shade and temperatures of 25C are beneficial for powdery mildew

27
Q

How does Powdery mildew affect the vine?

A

It stays on the buds and canes during winter. It then attacks green parts of the vine (shoots, inflorescences and grapes) reducing yields. Grapes can split and become targets to other infections.

28
Q

How can powdery mildew be managed?

A
  • manage the canopy and reduce shade
  • Application of sulfur to prevent and treat the disease
  • Systemic fungicides. The fungus can become resistant, and the application is limited in one year.
29
Q

Define Downy mildew

A

A disease caused by Peronospora, A water mould that lives within the vine tissue.

Rainfall and warm temperatures (20C) are beneficial por Downy mildew

30
Q

How does Downey mildew affect the vine?

A

It affects green parts of the plant, especially young leaves and flowers, reducing yields by defoliating the vine. Yellow, circular “oil spots” and then white downy fungal growth on the underside of leaves.

31
Q

How can downey mildew be managed?

A
  • Bordeaux mixture (i.e. copper sulfate and lime) is standard but has to be reapplied if more than 20 mm of rain.
  • Fungicides
  • Good drainage / open canopy that dries quickly are helpfull to avoid the fungus developing and spreading.
32
Q

Define Grey rot

A

A fungus that can cause damage the fruit. Botrytis Cinerea

33
Q

How does grey rot affect the vine?

A

Grapes with the point of entry are vulnerable to the development of spores. Affected grapes must be selected out of the harvest. It lowers yield and quality in the wine (color, body and aroma)

34
Q

How can grey rot be managed?

A
  • Selecting grapes varieties with thick skins
  • Avoiding split skins (pests)
  • Canopy management and removing leaves
  • Use of some fungicides (can cause the development of resistance)
  • Use of antagonistic bacteria (e.g. Bacillus subtillis) as biological control
35
Q

Define Eutypa dieback (dead arm)

A

A fungal trunk disease that leads to Rotten wood in vines and can affect whole vineyards.
Reduces yields and kills vines over a ten year period.
Spores can be spread by wind. Infection occurs at pruning wounds in moderate climate and during rain.
Stunted growth and yellow leaves.

36
Q

How can Eutypa dieback be managed?

A
  • Pruning late and applying fungicides to pruning wounds.
  • Cutting back affected trunks.
  • Some biological controls may be effective. Bacillus subtillis
  • Retrain the vine (sucker) or removing and replanting.
37
Q

Define Phomopsis cane & leaf spot

A

It is a fungal disease that causes a reduction in yield. It is more likely to appear in wet and cool springs followed by humidity and moderate temperatures.

38
Q

How does Phomopsis cane affect the vine?

A

Affected canes whiten and break. Shoots growing from affected canes develop brown cracks at their bases. Leaves are also affected.

39
Q

How can Phomopsis cane be managed?

A
  • The use of fungicides
  • Diseased and deadwood should be removed and burned
  • Improve airflow through canopy management to reduce the risk of the disease
40
Q

Define Esca

A

A complex fungal disease cause by a group of organisms, more common in warmer and drier climates (south of Europe and California)

41
Q

How does Esca affect the vine?

A

It enters the vine through pruning wounds. It can cause leaves to have stripes and spotting inside the wound. It reduces the yield of the plant and leads to its death within a few years.

42
Q

How can Esca be managed?

A

There are no chemical controls and prevention is the best option.
- Using disease free stock
- Trying new pruning techniques
- Not pruning in the rain
- Disinfecting pruning wounds

43
Q

Define Pierce’s disease

A

A bacterial disease that quickly kills vines. It is spread by the sharpshooter insect

44
Q

How does Pierce’s disease affect the vine?

A

The bacteria lives in the sap channels of the vines which it clogs leading to grape shriveling, dropping leaves, and the death of the vine between one and five years.

45
Q

How can Pierce’s disease be managed?

A
  • There is no chemical control for the bacteria
  • It can be controlled by reducing the insect that transmit the bacteria (Avoiding vineyards, near rivers, using insecticide, introducing wasp that feed on the sharpshooter)
  • Quarantine rules for the movement of plants
46
Q

Define grapevine yellows

A

A group of diseases caused by a type of bacteria. There is no treatment available. It is spread by vectors (leafhoppers and by nurseries selling untreated stock)

47
Q

How does Grapevine yellows affect the vines?

A
  • Delayed but burst
  • Drooping posture
  • Canopy turing yellow (in white varieties) or red (in red varieties)
  • Reduced yields in lower quality (high acidity and low sugar)
48
Q

How can grapevine yellows be managed?

A
  • The bacteria cannot be controlled
  • The focus is in controlling the vector using insecticides and cover crops that host leaf hoppers
  • Treat pruning wood in hot water in the nursery
49
Q

Define Fanleaf virus

A

A group of diseases caused the viruses. It can be transmitted by dagger nematodes.

50
Q

How does Fanleaf virus affect the vine?

A

Early shoot growth is stunted, canes can grow in distorted ways, and leaves are very pale, malformed and can look like a fan. Grape growers can lose most of the crop.

51
Q

How can Fanleaf be managed?

A
  • There is no cure for the disease and the vines will have to be removed and replaced
  • Testing the soil check for the presence of dagger nematodes
  • Using clean planting material
52
Q

Define Leafroll virus

A

A group of viral diseases widely present around the world. It is spread by grafting and by mealy bugs.

53
Q

How does leaf roll virus affect the vine?

A
  • Reduces the yield by up to half and affects quality -> slows down the growth of roots and shoots -> fruit take several additional weeks to ripen and have more acidity, less color and lower sugar levels.
  • Plant stores less carbohydrates.
  • Leaves have a downroll in autumn. Black grapes turn red and white grapes turn yellow.
54
Q

How can leaf roll virus be managed?

A
  • There is no cure for leaf roll Virus
  • Plants must be removed and replaced
  • Nurseries can screen vines for infections
  • Mealy bugs can be avoided by managing the canopy and introducing mealy bugs natural predators (ladybugs, lacewings,…)

WSET Level 4 Diploma in Wines | D1 Wine Production (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions