8 - HAZARDS, PESTS & DISEASES Flashcards

1
Q

What are the three effects of Hazards, pests and diseases on all of the world’s vineyards?

A
  1. Substantially reduced yields
  2. Negative effect on fruit quality
  3. Are expensive to manage/prevent
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2
Q

What are the eight hazards that can effect vineyards?

A
  1. Drought
  2. Excess of water
  3. Freeze
  4. Frost
  5. Hail
  6. Sunburn
  7. Fire
  8. Smoke taint
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3
Q

How much annual rainfall do cool climates and warm climates need?

A

Cool climates - 500mm

Warm climates - 750mm

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4
Q

What happens to a vine in drought? (x3)

A
  • Water stress leads to stomata in leaves closing, and photosynthesis halting.
  • Vine growth slows, development is reduced, ripening slows
  • Eventually leaves fall off and the vine dies.
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5
Q

What are the three management strategies for dealing with drought?

A
  1. Irrigation - must be at vineyard establishment, very expensive otherwise
  2. Select drought resistant rootstocks - rupestris, berlandieri.
  3. Select drought tolerant varieties - eg Grenache
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6
Q

What happens to a vine that is exposed to excess water? (x6)

A
  • Too much vegetative growth in summer
  • Too much shade
  • Competition for nutrients
  • Increase risk of fungal disease
  • Water logging roots in non-free-draining soils. Less oxygen intake, plant dies.
  • compacts soil, harder to work.
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7
Q

What are the three management strategies for dealing with excess water?

A
  1. Site selection - free drained soil site.
  2. Plant on slope to assist drainage
  3. Construct drainage system if necessary
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8
Q

A fully dormant vine is able to resist cold temperatures. But at what temperature is the vine at risk of damage or death during winter dormancy?

A

Below -20deg C

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9
Q

What parts of the vine are the most, and the second most at risk of winter freeze?

A

Most at risk - Graft of grafted vines
Second most at risk - Canes and cordon
(all are above ground)

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10
Q

What climates are most at risk of winter freeze? (give two examples)

A

Strong continental climates.

Eg. China and Canada

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11
Q

What are the four preventative measures that can help to avoid winter freeze?

A
  1. Aspect - planting on hillside can be 5C warmer than the valley floor.
  2. Proximity to water - large bodies of water will help to regulate temperatures (eg Finger Lakes)
  3. Plant where snow will be deepest as this can protect the vine.
  4. Choose varieties that can withstand cols temperatures (eg Riesling, Cabernet Franc, or non-Vinifera species or hybrids eg Concord)
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12
Q

What are the three non-preventative management strategies for dealing with winter freeze?

A
  1. ‘Hilling up’ - soil around the base of the vine
  2. Burying the vine - in extreme circumstances, very expensive for labour (eg China)
  3. Train the vine to have multiple trunks, so that any that are lost can be replaced.
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13
Q

What are the conditions that allow for frost to occur?

A

Cold air below 0C gathers just above the surface.

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14
Q

What are the effects of frost on the vine?

A

The cold air temperature freezes the water inside the buds or shoots.
If they are young, their water content is high and they can die.

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15
Q

In relation to frost, what happens to a vine that is planted in a consistently cool area?

A

The vine will adjust, and won’t start growing until the temperature is at least 10C

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16
Q

What kind of areas are most vulnerable to frost damage?

A

Moderate or warm climates where the vine has not adjusted, it starts growing and is then damaged.

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17
Q

What are the three problems with secondary shoots that grow after frost damage?

A
  1. They are less productive
  2. They will ripen slower
  3. They will be more likely to be affected by rain or frost in autumn
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18
Q

What are the two kinds of frost? Describe each one.

A
  1. Advective: large volumes of cold air move in from cold areas
  2. Radiative: result of cool, still nights where the radiant heat from the soil that has accumulated in the day time is lost at night. Collects in valleys when there is no wind.
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19
Q

What are the five methods for reducing the risk of frost damage?

A
  1. Site selection - avoid frost pockets.
  2. Delay pruning - which will delay budburst
  3. Choose late budding varieties - eg Riesling
  4. Train vines higher on the trellis where the air is warmer
  5. Avoid cover crops as bare soil will retain heat better.
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20
Q

What are the three management strategies that can be utilised when frost threatens?

A
  1. Sprinklers (aspersion). Preferably from pre existing irrigation systems (drip irrigation is ineffective)
  2. Wind machines - large fans that pull warm air from the inversion layer (costly, but investment justified if frost risk is 20%). Helicopters do the same thing.
  3. Oil or propane burners (smudge pots) or wax candles (bougies). Expensive for labour and materials, also fairly ineffectual. Also pollutants.
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21
Q

What is an ‘Inversion Layer’?

A

A layer of warm air 10m above the ground that can be 3-5C warmer than ground temperature. Large fans (or helicopters) can suck this air down to the ground to combat frost.

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22
Q

What are the effects of hail?

A
  • Damage to young leaves/shoots
  • Damage to ripening fruit - increasing fungal disease risk
  • Reduced yields in both current and next season
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23
Q

Hail is not very common worldwide, but what are two places that have suffered repeatedly?

A
  1. Burgundy (Champagne/Chablis)

2. Argentina (Mendoza)

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24
Q

Hail can be threatening at a number of stages, but when is it most detrimental?

A

After budburst and during ripening (spring & summer).

Buds can reshoot if the damage is early enough in the season.

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25
Q

What are the four management strategies for dealing with hail?

A
  1. Fire rockets with silver iodide into clouds to cause rain instead of hail.
  2. Net the fruit zone for protection where hail is common. (Mendoza). Not suitable for cooler climates as the nets provide shade.
  3. Play the odds with planting selection. Hail is selective, so keep continuity of supply by planting across a number of different plots.
  4. Vineyard insurance against hail. Consider the cost.
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26
Q

What are the conditions that allow for sunburn?

A

Prolonged hot weather with sun exposed grapes.

Risk increases when vines are already water stressed.

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27
Q

Why do grapes get sunburn but leaves and shoots don’t?

A

Grape transpiration is less effective that leaf transpiration, meaning that grapes release less water for cooling, and can therefore be a higher temperature than surrounding leaves.

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28
Q

What are the effects of sunburn? (x4)

A
  1. Reduced yield as burnt grapes need to removed at sorting.
  2. Negative impact on quality - browning of the skin, bitter taste
  3. Leads to scars on the grapes, and even death
  4. Skin damage leads to increase risk of disease.
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29
Q

What are the four management techniques for sunburn?

A
  1. Vineyard establishment - Aspect and orientation. N/S row orientation is best
  2. Canopy management to increase shading
  3. Irrigation to relieve water stress in a heatwave
  4. Agricultural sunscreen, or cloth/net shading
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30
Q

What are the climatic circumstances necessary for fire to occur?

A

Hot and dry climates,

Warmer, drier weather associated with climate change has increase occurances.

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31
Q

What regions have most recently been at risk from fires?

A

Australia, California, Chile

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32
Q

What geographical and vineyard features can increase risk of fire?

A

Close to wooded areas, pastural land or other crops.

Cover crops in the vineyard acting as fuel

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33
Q

What are the effects of fire?

A
  • Total loss of vineyard
  • Damage to property, trellising, irrigation
  • Long recovery
  • Loss of life
  • Smoke taint
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34
Q

What are the three preventative management strategies for fire?

A
  1. Install detectors/sprinklers
  2. Install and maintain a water tank.
  3. Train employees in what to do in the event of a fire.
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35
Q

What are the effects of smoke taint?

A
  • smoky or plastic like flavours
  • smoke aroma compounds enter the grape and bind with sugars to form aromaless precursors that are only detectable aromatically after fermentation
  • Can get worse with bottle age.
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36
Q

At what stage is smoke taint most detrimental?

A

During the growing season. Specifically increased from veraison onward

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37
Q

What are the four strategies for management of smoke taint affected grapes?

A

Note that nothing can remove it completely

  1. Testing - either analytically or by microferment
  2. Handling - hand picking, gentle whole bunch press, cooler ferment, less maceration (the compounds are thought to attach themselves to the inside of the skins)
  3. Flash detente or reverse osmosis.
  4. Blend with unaffected grapes/musts/wine
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38
Q

What are pests, and how do they interact with the vine?

A

Pests are organisms that attack the vine and impact it negatively. (INSECTS)
Some compete for water/nutrients.
Some attack the vine directly.
Some are the result of human travel (eg Phylloxera, Downy and Powdery mildew)
Some already exists in the vineyard area.

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39
Q

Because pests are difficult to control, what is it important for a producer to do before taking action?

A

Evaluate the cost benefit of acting on pests.

40
Q

What is Phylloxera and how does it effect the vine?

A

Phylloxera is an aphid-like bug that attacks the roots of the vine, and was responsible for the loss of 2/3 of the European vineyards in the late 19th Century. It feeds on and lays eggs in the roots causing cracks and swelling, weakening the roots and leading to rot and eventual death (5 years).

41
Q

What are the five symptoms of Phylloxera?

A
  1. Vines die of drought in patches that increase in size each year.
  2. Vine roots are covered in insects and yellow eggs.
  3. Swellings form on older roots.
  4. Pale green leaf galls form on underside of leaves.
  5. Slow, stunted shoots growth and leaf yellowing at three years.
42
Q

How is Phylloxera spread?

A
It came from North America initially, and was transported most likely on infected plant material.
It's spread by humans:
- on equipment
- on clothing
- in infected rootstocks or cuttings
- in irrigation water
43
Q

What soil provides immunity for Phylloxera?

A

Sandy soils

44
Q

Grafting onto American rootstocks is the widely adopted management method for Phylloxera. Which American vines species are used, and how is this process effective?

A

Species used are Berlandieri, Riparia and Rupestris.
It works because these species resist the entry of Phylloxera to the roots by forming a hard, corky layer that surrounds the eggs, sealing the wound and prevent invasion.

45
Q

Why do we graft American species over Vinifera?

A

Because of the undesirable flavours of these species, and to keep continuity of varieties in regions.

46
Q

What other technique has been developed as a result of grafting onto American rootstocks to stop Phylloxera?

A

Hybrids of multiple rootstocks to gain different advantages in the vineyard, such as resistance to lime to prevent chlorosis, resistance to nematodes, high pH soils and drought.

47
Q

What are the six kinds of pests that can effect the vine?

A
  1. Phylloxera
  2. Nematodes
  3. Grape Moths
  4. Spider Mites
  5. Birds
  6. Mammals
48
Q

What kind of insect is a Nematode?

A

Tiny worm. Lots of different kinds, common in soil, too small for the human eye.

49
Q

What are the two most common kinds of Nematodes that affect vines?

A

Root-knot Nematode

Dagger Nematode

50
Q

How do nematodes attack the vine?

A

Feed on the roots:

  • Halting vigour and lowering yields
  • Cause slow gradual decline
  • Can transmit viral disease
51
Q

Nematodes can already be present in the vineyard, but if not, how are they spread?

A

By people:

  • Unclean nursery stock
  • Irrigation water
  • Vehicles
52
Q

What are the three management methods for nematodes?

A
  1. Fallow soil for multiple years (expensive, lose crop)
  2. Soil fumigation (chemicals now mostly illegal), can plow in mustard plant (has biofumigant properties)
  3. Use nematode resistant rootstock (best option)
53
Q

How do grape moths attack the vine?

A
  • Feed on flowers and grapes.
  • Have multiple generations in one season so have prolonged effect on yields.
  • Make the wounds vulnerable to fungus and bacteria.
54
Q

What are the three most common kinds of Grape Moths, and where do they come from?

A
  1. Australia - Light brown apple moth
  2. Europe - European grape vine moth
  3. North America - Grape berry moth
55
Q

How are Grape Moths spread?

A

Can/have inadvertently be imported by humans.

56
Q

What are the three non-chemical management strategies for dealing with grape moths?

A

Biological:

  1. Bacterium (Bacillus thuringrensis)
  2. Pheromone capsules to disrupt mating
  3. Natural predators (wasps, some spiders)
57
Q

What are the two main kinds of Spider Mites and where do they come from?

A
  1. Pacific Spider Mite - California

2. Red & Yellow Spider Mite - Europe

58
Q

How do Spider Mites attack the vine?

A

Feeds on the surface cells of the leaves

59
Q

What are the four symptoms of Spider Mites?

A
  1. Discolouration
  2. Reduced photosynthesis
  3. Delayed ripening
  4. Lower yields
60
Q

What kind of climate conditions do Spider Mites thrive in/

A

Dusty. Thrive when the vines are already water stressed.

61
Q

What are the three management strategies for dealing with Spider Mites?

A
  1. Create an inhospitable environment - reduce dust, sprinklers, mulches, cover crops
  2. Predatory mites from other plant species
  3. Specific pesticides that only kill spider mites (expensive)
62
Q

What kind of vineyards are the most at risk for bird damage?

A

Isolated vineyards where there is no other food source.

63
Q

How do birds damage vineyards?

A

Will eat fruit and can destroy an entire crop of ripening grapes.
Allow bacteria/fungus to enter the grapes.

64
Q

What are the three management strategies for dealing with birds?

A
  1. Netting - costly, but worth it high value areas where birds are a constant threat (eg Mornington)
  2. Noisemakers/bird scarers - need to rotated
  3. Falcons - or other non fruit eating birds
65
Q

How do mammals attack vineyards? (x3)

A
  • Will eat fruit, shoots and leaves.
  • Damage to skins leading to disease risk.
  • Damage to structure like trellising
66
Q

What is the one management strategy for dealing with mammals?

A

Fencing - needs to be high enough and dug into the ground deep enough.

67
Q

What are the six kinds of fungal diseases?

A
  1. Powdery Mildew
  2. Downy Mildew
  3. Grey Rot
  4. Eutypa Dieback
  5. Phomopsis Cane & Leaf Spot
  6. Esca
68
Q

What kind vines are most susceptible to Powdery Mildew?

A
Vitis Vinifera (American less so)
Chardonnay and Cab Sauv (Riesling and PN less so)
69
Q

What causes Powdery Mildew?

A

A fungus - Erysiphe Necator

70
Q

What conditions are suitable for Powdery Mildew?

A
  • Optimal temperature of 25C
  • Likes a dense shady canopy
  • Doesn’t need humidity like most fungus.
71
Q

How does Powdery Mildew attack the vine?

A
  • It overwinters in buds and canes and then attacks young green parts of the vine
  • Attacks shoots, inflorescences and grapes
  • Starts as grey patches and then turns in black patches.
72
Q

What are the three management strategies for dealing with Powdery Mildew?

A
  1. Keep an open canopy to reduce density and shade (preferred method)
  2. Sulphur sprays for both prevention and treatment. (best to spray from just after budburst and up until veraison)
  3. Systemic Fungicides - penetrate the tissue, cannot be washed away, can be used less frequently but must rotated to avoid resistance building
73
Q

What is the cause of Downy Mildew?

A

A water mould that lives within the vine tissue

74
Q

How does Downy Mildew attack the vine?

A

Attacks green parts of the vine (especially young leaves and flowers). Defoliates and reduces yield.

75
Q

What conditions are necessary for Downy Mildew to develop?

A

Rainfall, and at least 20C

76
Q

What are the symptoms of Downy Mildew?

A

Yellow oil spots and then white, downy fungal growth on the underside of the leaves

77
Q

When in the season does Downy Mildew pose the greatest risk?

A

Warm springs and warm, wet summers.

78
Q

What are the management strategies for Downy Mildew?

A
  1. Copper salt sprays (aka Bordeaux Mixture) standard since 1880s, only effective until 20mm of rain
  2. Fungicides - from 1 month after budburst until veraison
  3. Good drainage, open canopy to keep dry.
79
Q

What is Grey Rot also known as?

A

Botrytis Cinerea

80
Q

How does Grey Rot attack the vine?

A

Enters through damage to grape skins (splitting, bug/insect damage, tight bunches). Reduces yield and and quality (colour, body, aroma/flavour)

81
Q

What kind of conditions pose the greatest risk for Grey Rot?

A
  • Rainfall/humidty
  • Tight buches
  • Dense canopy
  • Thin skinned varieties like PN and Semillon
82
Q

What are the three preventative management strategies for Grey Rot?

A
  1. Selecting thick skinned varieties (eg Petit Verdot)
  2. Preventing damage to skins from pests
  3. Keeping an open canopy, remove leaves from around bunches
83
Q

What are the two treatment management strategies for dealing with Grey Rot?

A
  1. Fungicides at key times (end of each grape development stage)
  2. Antagonistic Bacteria (Bacillus Subtillis)
    NB Copper and Sulphur are NOT effective treatments.
84
Q

What is does the colloquial term ‘dead arm’ refer to?

A

Eutypa Dieback

85
Q

How does Eutypa Dieback attack the vine?

A

It attacks the trunk.
Causes rotten wood, and can affect whole vineyards.
Kills over a 10 year period.

86
Q

How is Eutypa Dieback spread?

A

Fungal spores are spread by wind.

Infection occurs through pruning wounds, especially during rain.

87
Q

What are the early symptoms of Eutypa Dieback and when do they start to show?

A

Yellow leaves, short shoots.

In spring.

88
Q

Which three varieties and three regions are most commonly effected by Eutypa Dieback?

A

Grenache, Cabernet Sauvignon, Sauvignon Blanc

South Australia, South West France, California.

89
Q

What are the four management strategies for dealing with Eutypa Dieback?

A
  1. Can prune late and apply fungicide to wounds
  2. Cut back infected trunk (5-10cm beyond) and burn the wood to avoid spores spreading
  3. Antagonistic Bacteria (Bacillus Subtillis)
  4. Last resort is to retrain a new trunk from a sucker or shoot, or replant the vine entirely.
90
Q

What conditions allow for the development of Phomopsis Cane & Leaf Spot?

A

Cool wet springs, followed by humidity and moderate temperatures

91
Q

What are the symptoms of Phomopsis Cane & Leaf Spot?

A

Canes whiten and break off easily. Defoliation.

92
Q

What variety is most susceptible to Phomopsis Cane & Leaf Spot?

A

Grenache. (Cabernet Sauvignon is less so)

93
Q

What are the three management strategies for dealing with Phomopsis Cane & Leaf Spot?

A
  1. Fungicides applied three weeks after budburst and then every 2 weeks if wet conditions continue
  2. Diseased wood removed and burnt
  3. Prune early or late - just not in rainy weather
94
Q

What is ESCA, and where is it most prevalent?

A

A complex fungal disease that is most prevalent in warner, drier climates such as California and Southern Europe.

95
Q

How is ESCA spread?

A

Through spores entering pruning wounds.

96
Q

What are the symptoms of ESCA?

A

Tiger striping of the leaves and spotting inside the wood.

97
Q

What is the management strategy for dealing with ESCA?

A

There are no chemical controls, so must be preventative - disease free stock, careful pruning, not pruning in the rain, remove prunings promptly, disinfect pruning wounds.