Hazards, Pests and Diseases Flashcards

1
Q

What is amount of rain needed for good quality fruit

A

For cool climates: 500mm/19.6 in

For warm climates: 750mm/29.5in.

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2
Q

Name all of the hazards vineyards can face?

A
Drought
Excessive water
Untimely Rain
Hail
Freeze
Frost
Fire
Smoke Taint
Sunburn
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3
Q

What happens to the vine when there is a lack of water?

A
Vines close the stomata to retain water
reduced/stopping of photosynthesis
Growth of the vine shuts down
grape sized is reduced
ripening slows down.

If it is a prolonged drought the vines can lose their leaves and die

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4
Q

Is irrigation legal everywhere?

A

No

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5
Q

How can extended drought affect the final wine?

A

When the plant shuts/slows down due to lack of water, ripening will also slow down.

This can lead to unripe grapes and lower yields.

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6
Q

What are the managements options for drought?

A
  • Irrigation (where allowed by law)
  • If it is a new vineyard being planted, drought-resistance root-stock should be high on the list of priorities
    Choosing drought tolerant varieties
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7
Q

What are examples of root-stocks that are drought-resistant?

A

Root-stocks based on V. rupestris and V. berlandieri

110R and 140R

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8
Q

What are the negative affects of excess water?

A

Too much vegetative growth that will compete with grape ripening
Excessive shading due to vegetative growth
Higher risk of fungal diseases due to high humidity
If the soils are not free draining, then waterlogging can occur, reducing oxygen available to the roots (which can lead to death)
Waterlogging can also lead to compacted soils, making them harder to work and uncontrolled water run-off.

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9
Q

What are the management options for excess water?

A

Proper site selection when planting the vineyard to insure that it is planted on a slope or on free-draining soils or the construction of a drainage system

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10
Q

What are the side-effects of untimely rainfall?

A
  • If the rain comes during pollination and fruit set it can lead to millerandage or coulure, reducing crop size and potentially lowering the quality
  • Mid-season rain can reduce the rate of ripening
  • Heavy rainfall close to harvest can lead to water swelling, reducing the concentration of the must, potentially splitting of the skins leading to grape rot.
  • Rains near harvest can also make it harder to harvest if using mechanical harvesters on clay soils
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11
Q

What are the management options for untimely rainfall?

A

Nothing can be done about the rain, but having a good site (on a slope), soil condition and good drainage can mitigate some of the effects.
Monitoring the forecast and deciding if they would rather harvest with potentially less-ripe grapes vs. losing some, if not all, of their crop.

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12
Q

If temperatures fall below _______, the vine can be seriously damaged or killed by winter freeze

A

-20°C/-4°F

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13
Q

What is the most susceptible part of a grafted vine?

A

Where the graft is

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14
Q

What are the management options for a potential winter freeze? (There are a lot)

A

Site Selection:
Hillsides can be 5°C/9°F warmer than the valley floor
Vineyards near large or deep bodies of water benefit from a moderating affect
Vines should be planted where the snow settles most thickly, as a deep layer of snow will protect the vines.

Choice of varieties:
Some varieties are most freeze resilient (Riesling and Cab Franc)
Some American and Mongolian vine species are extremely winter hardy, as are they hybrids with these species

Protecting the vines:
Building up the soil around the graft (hilling up) is common in colder regions since the soils underground are only a few degrees below freezing.
Burying the vines is another approach used in extreme climates, but is very costly due to the amount of labor needed.
Vines can be pruned to have several trunks in-case on is killed during the winter.

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15
Q

What is a frost defined as?

A

A frost occurs when the cold air below freezing collects at ground level.

This will freeze the water in the vine’s growing buds and shoots.

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16
Q

When are frost the most damaging to the grape vine?

A

Right after budburst

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17
Q

Name the two types of frost

A

Advective Frost: cause by large volumes of cold air moving in from cold areas

Radiative Frost: the result of heat being lost on still, cool nights.

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18
Q

What are some ways that frost risk can be reduced?

A

Site Selection: making sure you don’t pick a frost pocket, or getting a hillside location

Delaying pruning: by doing so, budburst is pushed back into warmer months

Choosing late budding varietals like Riesling

Trainging vines higher off the ground

Having bare soil between the vines so it can absorb more heat during the day

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19
Q

What are the three main options for vineyard owners to use when frost threatens?

A

Water Sprinklers (also known as aspersion)

Wind Machines

Oil or Propane gas heaters

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20
Q

How do water sprinkles help prevent frost from setting?

A

As the water freezes around the plant, it releases the latent heat, protecting the plant.

  • The system must be kept on until the temp rises
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21
Q

How do wind machines help prevent frost from settling?

A

Wind machines are large fans (13 to 23ft tall) that pull warm air from above down to ground level, thereby raising the temp.

  • Helicopters can be used, but generally aren’t due to the large expense of owning one
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22
Q

What is an inversion layer?

A

It is a zone of warm air 10m/33ft above the ground that is usually 5-9°F warmer

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23
Q

What are the drawbacks to using Oil or Propane burners ?

A

High cost of fuel and labor, low heating efficiency and contributions to air pollution

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24
Q

What is hail?

A

Frozen pellets of rain

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25
Q

What are some of the management options for hail?

A

Firing rockets into thunderclouds, seeding them with silver iodide which causes rainfall rather than hail.

Putting nets on to protect the ripening grapes (usually done in regions with high levels of sunlight.

Having numerous plots in different areas

Growers may have to consider the additional cost of crop insurance against hail.

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26
Q

Describe sunburn

A

In prolonged hot weather, grapes transpiration is much more limited and as a result, grapes can reach higher temperatures and become burnt.

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27
Q

What are some of the negatives associated with Sunburn?

A
  • Scars on the skin of the grape
  • In extreme cases, eventual death on the grape
  • Grape quality suffers
  • Browning of the grape can give a bitter taste
  • Higher susceptibility to rot
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28
Q

What are some of the management options for Sunburn?

A
  • Row orientation and aspect when designing a new vineyard
  • Manage the amount of sun exposure with canopy management
  • If there is a heatwave in the forecast, additional irrigation (where allowed) may be used
  • A special agricultural sunscreen spray can be applied or the vines can be shaded by cloth/net.
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29
Q

What are the management options for fighting fires

A
  • Installing fire detectors and sprinklers
  • Installing and maintaining a water tank
  • Providing employee training for action in the event of an emergency
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30
Q

What is smoke taint?

A

Aroma compounds in smoke near or around the vineyard that is absorbed into the grape. Those compounds then bind with the sugars and form aroma-less precursors.

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31
Q

List the management options for smoke taint?

A
  • How the grapes are handled can reduce the effect of smoke taint
  • Hand harvesting, gentle or whole bunch pressing, and lower fermentation temperatures and reduced maceration time
  • Flash Detente and reverse osmosis can help mitigate the smoke taint
  • Chemical analysis in the days leading up to harvest to see the extent of the problem.
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32
Q

List all of the different vineyard pest

A
  • Phylloxera
  • Nematodes
  • Grape Moths
  • Spider Mites
  • Birds
  • Mammals
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33
Q

Describe phylloxera

A

Phylloxera is an aphid-like insect that feeds on, and lays eggs, on the roots of grape vines.

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34
Q

How does phylloxera affect the vine roots?

A

It weakens vine roots and causes swellings and cracks, which then lead to rot.

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35
Q

What are they symptoms of phylloxera infestation?

A
  • Vines die of drought in patches that increase in size over the years
  • vine roots are covered with the insects and their eggs
  • swellings on older roots
  • pale green leaf galls on the underside of the leaves
  • Slow, stunted shoot growth and leaf yellowing around 3 years
  • plants usually die after 5 years
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36
Q

List the management options for phylloxera

A

Phylloxera resistant root-stock

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37
Q

Describe what nematodes are

A

Nematodes are tiny worms that are very common in soil.

38
Q

How is the fanleaf virus spread?

A

By the dagger nematode

39
Q

What are the two most commonly occurring nematodes?

A

Dagger and root-knot nematodes

40
Q

Sometimes nematodes are already present in the soil, but what are some other ways that they are spread?

A
  • Unclear nursery stock
  • Irrigation water
  • Vineyard equipment/vehicles
41
Q

What are the recommendations for managing nematodes?

A
  • Leaving the soil fallow for a number of years (not economical for everyone though as no crop is produced).
  • Fumigate the soil
  • Nematode-resistant root-stock
42
Q

What are the two ways that vineyard owners can fumigate their soils against nematodes?

A

Either by using chemicals (most of these chemicals are now banned in most regions), or by using mustard plants as a cover crop which contain compounds that work as bio-fumigants that can kill nematodes.

43
Q

What are grape moths?

A

Moths that attack vines by feeding on flowers and grapes.

Many species have several generations per season, attacking flowers in the spring and then grapes later in the year.

44
Q

Do the wounds produced by grapes moths lead to greater disease pressure?

A

Yes, the wounds created are then vulnerable to other bacteria and fungi

45
Q

What are the management options for Grape Moths?

A

Biological controls:

  • Bacillus thuringiensis produces a substance that are toxic to the moths
  • Pheromone capsules that can disrupt mating
  • Natural predators (parasitic wasp, green lacewings, and some spider species)

Insecticides can also be used.

46
Q

How do spider mites damage vines?

A

They feed on the surface cells of leaves which can lead to:

  • discoloration of the leaves
  • a reduction in photosynthesis
  • delayed ripening
  • reduction in yields
47
Q

What are the management options to dealing with Spider Mites?

A
  • Making the environment inhospitable to them by the use of water sprinklers and/or cover crops to reduce dust
  • Encourage predatory mites that feed on spider mites
  • General pesticides
48
Q

What conditions can lead to a influx of spider mites

A

Dusty and dry conditions

49
Q

Fuck Birds

A

Fuck Birds

50
Q

List all of the different fungal diseases

A
  • Powdery Mildew
  • Downy Mildew
  • Grey Rot
  • Eutypa Dieback
  • Phomopsis cane and Leaf Spot
  • Esca
51
Q

What is the fungus that causes grapevine powdery mildew?

A

Erysiphe necator, commonly known as Oidium tuckeri

52
Q

True or False,

Powdery mildew can survive through the winter?

A

True, it can live in the buds and on canes

53
Q

What parts of the vine does powdery mildew attack?

A

Powdery mildew attacks the young, green parts of the vine.

It usually starts off in dull grey patches, and become black as they spread. These patches can damage young shoots, inflorescences and grapes, reducing yields.

54
Q

What makes Powdery Mildew unique compared to other mildews?

A

It does not require high humidity, so it can spread in relatively dry conditions. Especially in dense, shady canopies.

55
Q

List the management options for Powdery Mildew

A
  • Keeping an open canopy to reduce shading and leaf density (preferred approach)
  • Applications of sulfur help prevent the disease and treat it. Growers will spray the vines from a couple of weeks after budburst and up to verasion.
  • Systemic fungicides can be effective and since they penetrate the green tissue, are not washed off. (The fungus can become resistant though, so only a limited number of applications can be made during the year.)
56
Q

What causes downy mildew?

A

Peronospora, a water mold that lives within the vine tissue, not on the surface.

57
Q

How does downy mildew attack a vine?

A

It attacks the green parts of the plants, especially the young leaves and flowers, reducing yields by defoliating the vines.

58
Q

What conditions does downy mildew need to thrive?

A

Rainfall and warm temperatures (20°C / 68°F)

59
Q

What are the symptoms of downy mildew?

A

yellow, circular ‘oil spots’ and then white, downy fungal growth on the underside of the leaves

60
Q

How do you treat Downy Mildew?

A
  • Traditional sprays (i.e. Bordeaux mixture) can be used to prevent its spread.
  • Other fungicides can also be used. These should be applied from about a month after budburst to verasion
  • Good drainage and an open canopy that dries quickly are helpful to avoid it developing and spreading.
61
Q

What is the scientific name for Grey Rot?

A

Botrytis cinerea

62
Q

How can grey rot affect a crop?

A

It causes significant damage to the fruit. It will also result in loss of yield and drop the quality of the final wine (color, body, and aromas/flavors.)

63
Q

How does Grey Rot get into the grapes?

A

If there are any points of entry into the grape such as:

  • Breaking open due to water swelling
  • Grapes rubbing against each other in tight bunches
  • Being punctured by birds/insects
  • If the flowers are affected, the fungus can stay dormant and re-emerge after verasion.
64
Q

How do you manage Grey Rot?

A
  • Selecting grape varieties that have small grapes with think skins
  • Keeping an open canopy and removing the leafs around grape clusters
  • Spraying at key points in the season like when flowering is nearly complete. (fungicide resistance is still a worry)
65
Q

What is the benign form of Botrytis Cinerea?

A

Noble rot

66
Q

What is the other name for Eutypa Dieback?

A

Dead arm

67
Q

Describe what Eutypa Dieback is

A

It is a fungal trunk disease that will lead to rotten wood in vines, and can affect a whole vineyard.

68
Q

How does Eutypa Dieback affect the vine?

A

It reduces yields significantly and kills vines over a ten-year period if not tackled.

The effects can be seen in the spring with short young shoots and yellow leaves.

69
Q

How does Eutypa Dieback spread?

A

Spores are spread by the wind and penetrates the vine through pruning wounds, especially during rain.

70
Q

List the management options for battling Eutypa Dieback

A
  • Pruning late and applying fungicides can be effective.
  • Affected trunks need to be cut 2-4 inches/5-10 cm beyond the visible symptoms and then treated with fungicides
  • Burning the dead wood to avoid the spores spreading
  • If a vine is heavily affected, either retraining the vine, or removing the vine and replanting are recommended.
71
Q

Describe phomopsis

A

Phomopsis is a funal disease that causes a reduction in crops. Infected canes whiten and break off easily.

72
Q

How do you manage Phomopsis?

A
  • Apply fungicides 3 weeks after budburst and then every 2 weeks if wet conditions persist.
  • Removing and burning diseased wood
  • Prune early or late, and not in rainy weather
73
Q

What is Esca?

A

A complex fungal disease that is caused by a group of organisms.

It is particularly prevalent in warmer and drier climates, and typically enters through pruning wounds.

74
Q

How does Ecsa attack the vine?

A

It causes tiger-striping of the leaves and spotting inside of the wood.

Esca also reduces the yields of the plant and eventually kills it.

75
Q

Is Ecsa treatable?

A

It is not, it is only treat able. Treatment options include:

  • Not pruning in the rain
  • Promptly removing infected wood out of the vineyard and burning it
  • Disinfecting pruning wounds
76
Q

What are the two main bacterial diseases that plague vineyards?

A

Pierce’s Disease and Grapevine Yellows

77
Q

What is Pierce’s Disease and how is it spread?

A

It is a bacterium that lives in the sap channels of vines, which it then clogs, eventually killing the vine.

It is spread by the sharpshooter insect

78
Q

Define Grapevine Yellows

A

Grapevine Yellows are a group of diseases caused by a type of bacteria. It is a serious threat to viticulture as there is not treatment option currently available.

79
Q

What is a vector?

A

an organism, typically a biting insect or tick, that transmits a disease or parasite from one animal or plant to another

80
Q

What are the vector(s) for Pierce’s Disease?

A

Sharpshooters

81
Q

What are the vector(s) for Grapevine Yellows?

A

Leaf hoppers, and nurseries that sell untreated and diseased root-stock.

82
Q

List the symptoms of for Grapevine Yellows

A
  • Delayed budburst
  • Dropping posture because new shoots fail to lignify
  • The canopy changes colors (yellow in white varieties, red in black varieties).
  • Depending on the strain, the vine can either die or recover
83
Q

What can you do to manage grapevine yellows?

A
  • Focus on controlling the vectors by using insecticides and plants hosting the leafhoppers should be removed.
  • In the nursery, bathing the pruning wood in hot water will kill the disease
84
Q

What are the two main viruses that plague vineyards?

A

The Fanleaf Virus and Leafroll Virus

85
Q

List the symptoms for the Fanleaf Virus

A
  • Early shoot and cane growth is distorted

- Leaves are very pale, malformed and can look like a fan

86
Q

How is/was the Fanleaf Virus spread?

A

It spread quickly via infected plant material following the move to grafted vines post-phylloxera

Now it is slowly spread by the dagger nematode

87
Q

What are the ways to manage the Fanleaf Virus?

A

There is no cure, so infected material will eventually need to be removed.

If planting a new vineyard, or replanting, soil test should be done to check for dagger nematodes. Also, only virus-tested, clean planting material should be used.

88
Q

How is the the Leafroll Virus spread?

A

By infected planting material and by mealy bugs.

89
Q

Does the Leafroll Virus kill the infected vines?

A

No, but it can reduce yields up to 1/2 and negatively affect the quality of the grapes.

90
Q

How does Leafroll affect the quality of the fruit and overall health of the vine?

A

Surviving fruit may take more time to ripen and have more acidity, less color and lower sugar levels.

The virus slows down the growth of roots and shoots. The plant also stores less carbs.

91
Q

Does the Leafroll Virus always present the same?

A

No, the symptoms are not always clear, so some lab testing may need to be done.

92
Q

What are the ways to prevent the Leafroll Virus?

A
  • Remove any unproductive vines and replant with virus free rootstock
  • Having more open canopies can help reduce the presence of mealy bugs
  • Insecticides do not work due to the bug’s waxy coating so steps can be taken to encourage the mealy bugs natural predators.