8.2 Pests Flashcards

1
Q

What is phylloxera?

A
  • Aphid-like insect that feeds on and lays eggs on the roots of grape vines.
  • Weakens vine roots and causes swellings and cracks, which then lead to rot.
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2
Q

How does phylloxera spread?

A
  • Crawling
  • Flying
  • Transported by humans
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3
Q

What are the 5 main symptoms of phylloxera?

A
  1. Vines die of drought in patches that increase in size year by year
  2. Vine roots are covered with the insects surrounded by yellow eggs
  3. Swellings on older roots
  4. Pale green leaf galls on the under-surface of the leaves
  5. Slow, stunted shoot growth and leaf yellowing appears in around three years, the plant dies after around five years.
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4
Q

When was phylloxera identified? Where? Where did it originate?

A
  • Identified: 1863
  • Identified in: Europe
  • Originated in: USA
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5
Q

What was the effect of phylloxera on Europe?

A

Destroyed two-thirds of the European vineyard in the late nineteenth century.

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6
Q

What was the effect of phylloxera on USA?

A

Nothing. American species were naturally resistant.

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7
Q

What types of soil is immune to phylloxera?

A

Sandy

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8
Q

What are management options for phylloxera?

A
  1. Planting American vine species (not ideal)
  2. Grafting European varieties onto rootstocks from single American vines (not ideal)
  3. Grafting European varieties onto rootstocks hybrids from multiple American vines (ideal)
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9
Q

Name the 3 American vine species that offer the most protection against phylloxera.

A
  • V. berlandieri
  • V. riparia
  • V. rupestris
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10
Q

Describe how the American vine species protect against phylloxera.

A

They form hard, corky layers that surround the eggs, sealing the wounds and preventing invasion by bacteria or fungi.

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11
Q

Why aren’t American vine species typically used? What are they typically used for?

A

They produce different and undesirable aromas in the resulting wine. The solution was to graft European varieties onto rootstocks from American vines.

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12
Q

What tends to happen when grafting onto the rootstocks of single American varieties? Why?

A
  • Soils of Europe are typically calcareous
  • American varieties have little lime tolerance
  • Thus, vines suffered from chlorosis turning the leaves yellow, halting photosynthesis and reducing yields and quality
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13
Q

How does one choose which rootstock to use?

A
  • There are many rootstocks, often with complex parentage, that can deal with a number of problems
    (phylloxera, nematodes, extremes of soil pH, water stress, salinity)
  • Goal is to match the appropriate rootstock to:
    1. the vineyard soil
    2. the pests to be combatted
    3. the level of vigour desired
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14
Q

What is a main disadvantages of planting on rootstocks?

A

Significantly more expensive than on the vines own roots

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15
Q

What are nematodes?

A

Tiny worms that live in the soil, typically too small to be seen by the naked eye.

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16
Q

How are nematodes harmful to vines?

A
  • Feed off vine roots

- Transmit viral diseases

17
Q

Name 2 of the most commonly occurring nematodes.

A
  1. Root-knot nematode

2. Dagger nematode

18
Q

How do nematodes spread?

A
  • present in the soil already
  • unclean nursery stock
  • irrigation water
  • vehicles
19
Q

How can nematodes be eliminated?

A

They can’t. They can only be managed.

20
Q

How are nematodes managed? What happens first? What is typically the best solution?

A

Soil samples are analysed in a lab to determine the number and type of nematodes present.

  • Leave the soil fallow for a number of years (costly, no crop)
  • Fumigate the soil.
  • Plough in a cover crop of mustard plant, which contains compounds that work as biofumigants, killing nematodes.
  • For most, the best solution is the use of nematode-resistant rootstocks
21
Q

What are grape moths and how do they affect vines?

A
  • Many species of moths that feed on flowers and grapes, damaging vines
  • Wounds created are then vulnerable to further attack from bacteria and fungi, including botrytis
22
Q

Name the 3 most common types of grape moths and the regions they affect.

A
  • Light brown apple moth (Australia)
  • European grapevine moth (southern Europe)
  • Grape berry moth (central and eastern North America)
23
Q

What happened to Napa Valley in 2009?

A
  • European grapevine moth was introduced accidentally

- Eradicated in 2016

24
Q

How are grape moths managed?

A
  1. Biological controls include the use of:
    - - the bacterium Bacillus thuringiensis (which produces substances that are toxic to the moths)
    - - use of pheromone capsules to disrupt mating (‘sexual confusion’)
    - - natural predators (parasitic wasps, green lacewings, some spider species).
  2. Insecticides can be used.
25
Q

Describe the effects of spider mites on vines.

A

They feed on the surface cells of leaves:

    • Discoloration
    • Reduction in photosynthesis
  • – Delayed ripening
  • – Reduction in yields

Vary from region to region

26
Q

Name the most common types of spider mites and the regions they affect.

A
  • Pacific spider mite (California)
  • Red spider mite (Europe)
  • Two kinds of yellow spider mite (Europe)
27
Q

Where do spider mites thrive?

A

Dusty conditions

28
Q

When are spider mites the most damaging?

A

When vines are already water stressed

29
Q

How are spider mites managed?

A
  1. Reduce dust: Make the environment inhospitable by the use of water sprinklers, cover crop, mulches
  2. Encourage predatory mites (by planting host species) that feed on spider mites.
  3. General pesticides may kill beneficial predatory mites. Specific sprays can be applied to kill only the mites that are problematic in the vineyard, but this can add to costs.
30
Q

Name 2 other insect pests and how they damage vines.

A
  1. Leafhoppers (they cause direct damage to vine leaves)

2. Ladybirds (which can cause taints to the wine if they are amongst harvested grapes)

31
Q

Why can birds be can be a serious threat to vine growers?

A
  • They feed on an entire crop of grapes as they ripen

- Damage allows bacteria and fungi to enter bunches, which leads to rot.

32
Q

What vineyards are most in danger of birds?

A

Isolated vineyards that provide the only source of food in an area

33
Q

Name 1 species of bird that often attack vineyards.

A

Starlings

34
Q

What are the management options for birds?

A
  1. Netting - Costly

2. Bird scarers or noises (must be rotated so birds don’t get used to them) - Falcons

35
Q

Why can mammals be can be a serious threat to vine growers?

A
  • Eating shoots, grapes and leaves
  • Breaking the skins of grapes (vulnerable to rot)
  • Damaging structures such as trellising
36
Q

Name some examples of animal pests in different parts of the world.

A
  • Deer
  • Rabbits
  • Kangaroos
  • Raccoons
  • Wild boar
  • Baboons
37
Q

What is the main management option for mammals?

A

Fencing

- Must be sufficiently high and sunk into soil (for burrowing animals)