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WSET 4 > D8: Hazards, Pests and Diseases > Flashcards

D8: Hazards, Pests and Diseases Flashcards

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1
Q

Name 9 hazards which can have an impact on grape growing

A
  • drought
  • excess water
  • untimely rainfall
  • freeze
  • frosts
  • hail
  • sunburn
  • fire
  • smoke taint
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2
Q

DROUGHT

what is the minimum amount of water a vine needs in a) cool climate and b) warm climates?

A

Cool: 500mm

Warm: at least 750mm

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3
Q

DROUGHT

what happens to the vine with lack of water?

A
  • stomata closes in order to limit water loss
  • this reduces photosynthesis which then stops the plant growing. This impacts the size of the grapes and ripening also slows
  • causes unripe grape
  • if has lack of water for too long, vines lose their leaves and die
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4
Q

DROUGHT

What can happen to vineyards where water is scarce and irrigation is limited? Give examples

A
  • can lose whole vineyards

EXAMPLE: Olifants River in South Africa

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5
Q

DROUGHT

What are the management options for drought?

A
  • irrigation (where permitted)
  • drought resistant rootstock (e.g. 110R or 140R)
  • drought tolerant grapes (e.g. garnarcha)
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6
Q

Name two drought resistant rootstock

A

100R and 140R

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7
Q

Name a drought tolerant grape variety

A

Garnacha

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8
Q

EXCESS WATER

Excessive water can lead to…

A

1) excessive vegetative growth

  • too shady, too much competition for nutrients
  • leads to less ripeness

2) fungal disease due to high humidity
3) waterlogged soils

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9
Q

EXCESS WATER

What is the impact of waterlogged soils?

A
  • reduces oxygen in soil
  • slows growth
  • eventually kills the vine
  • causes compaction in soil so difficult to work and can cause uncontrolled water run off
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10
Q

EXCESS WATER

What are the management options for Excess Water?

A
  • slope planting
  • free draining soils
  • construction of drainage systems
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11
Q

UNTIMELY RAINFALL

What two conditions can this cause during pollination and fruit set?

A
  • coulure
  • millerandage
  • reduces crop size and lowers quality
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12
Q

UNTIMELY RAINFALL

What else does this impact?

A
  • rate and ripening of fruit as you want some water deficiency before veraison
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13
Q

UNTIMELY RAINFALL

What can happen if there is rainfall before harvest

A
  • swollen and splitting grapes
  • rot
  • also makes machine harvesting difficult
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14
Q

UNTIMELY RAINFALL

What are the management options?

A
  • think about site choice, soil and drainage adequacy

- monitoring weather around the harvest

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15
Q

FREEZE

At what temperature can a vine be killed or damaged?

A
  • below -20 degrees/-4 Fahrenheit
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16
Q

FREEZE

What part of the vine is most at risk?

A
  • graft

- then canes/cordons

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17
Q

FREEZE

What three places are most at risk

A
  • Canada
  • Washington State
  • China
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18
Q

FREEZE

What are the management options?

A
  • site selection
    • hillsides are warmer than plains
    • near a body of water
    • plant where deep snow settles as protects vine
  • varieties
    • resilient (cab franc, riesling)
    • winter hardy (Concord - tolerant up to -35 degrees or other mongolian varieties)
  • protection
    • hilling up/building soil around vine graft
    • burying vines (often seen in China)
    • prune vines to have several trunks so can replace any that are killed
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19
Q

FROSTS

What happens when freeze occurs?

A
  • when cold air below zero degrees collects at ground level, it freezes water in vines growing buds and shoots
  • will kills any newly burst buds or young shoots which have a high water content
  • impacts yield and quality
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20
Q

FROSTS

Where is the risk highest for frost?

A
  • areas with cool and warm climates

- if buds are killed, secondary buds take much longer to grow and establish

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21
Q

FROSTS

What are the two different types of frost which can occur?

A

ADVECTIVE FROSTS
- large volumes of cold air moving in from very cold areas

RADIATIVE FROSTS

  • result of heat being lost on still, cool nights.
  • allows for layer of freezing, cold air to develop just above the surface of soil.
  • collects in valley bottoms
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22
Q

FROSTS

What are the management options?

A
  • site selection (avoiding frost pockets)
  • delay pruning so as to delay budburst
  • chose late budding varieties
  • train vines high
  • have bare soil between vines so as to radiate heat at night
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23
Q

FROSTS

What can you do when frost threatens?

A
  • water sprinklers: as water freezes around the plant, it releases latent heat and protects the plant
  • wind machines: pulls warm air from above down to the ground level
    • needs INVERSION LAYER: warm air zone 10m above ground
    • expensive but main cost is upfront
  • oil or propane heathers: placed around vineyards and lit when risk of frost
    • costly, labour intensive and not environmentally friendly
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24
Q

HAIL

What damage can hail do to a vineyard?

A
  • damage and rip young shoots and leaves
  • damage grapes and become entry points for botrytis and disease
  • reduce yield at the time and in future seasons
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25
Q

HAIL

What are the management options for hail?

A
  • rockets fired at thunderclouds (so it falls as rain and not as hail)
  • net fruit zone (can only do in high sunlight areas as it causes shading)
  • have plots in different areas
  • crop insurance
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26
Q

SUNBURN

  • what issues does sunburn cause?
A
  • limits grape transpiration so grapes reach higher temperatures than the leaves and become burnt
  • higher risk if vine is already water stressed
  • can cause scars on skins and leads to death of the grape
  • negatively impacts grape quality (browning, bitter taste, risk of rot)
  • need to ensure sunburnt grapes are removed at sorting which decreases yield
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27
Q

SUNBURN

What are the management options?

A
  • row orientation and aspect so can manage sun exposure
  • canopy management (so can try and shade fruit)
  • additional irrigation in a heatwave
  • agricultural sunscreen can be applied or shade can be provided with cloth or netting
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28
Q

FIRE

Where are the areas with the highest incidences of fire?

A
  • california
  • australia
  • chile
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29
Q

FIRE

What are the worst conditions/places for areas with high fire risk?

A
  • near woods
  • near pastures
  • crops using mulch

** all are fire risks

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30
Q

FIRE

What are the management options?

A
  • installing fire detectors and sprinklers
  • water tanks
  • employee training
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31
Q

SMOKE TAINT

What is the impact of smoke taint?

A
  • can cause ‘smoky’ or ‘plastic’ aromas in final wine
  • impact increases from veraison onwards
  • aroma compounds in smoke can be absorbed by grapes
  • once in grapes, compounds bind with sugars and form aroma-less precursors
    • these only become aromatic during fermentation and develop/increase with ageing
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32
Q

SMOKE TAINT

What are the management options?

A
  • can test must analytically by MICRO-VINIFICATIONS to see if there is a problem
  • hand harvesting, gentle or whole-bunch pressing, lower fermenting temperatures and reduce maceration can reduce uptake of compounds
  • flash detente and reverse osmosis can help but won’t remove taint completely
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33
Q

What impact can PESTS have?

A
  • compete for water or nutrients
  • can directly attack the vine and/or grapes so affect yield and quality
  • some pests and diseases are result of being transferred to territory with no previous resistance e.g phylloxera in Europe
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34
Q

PHYLLOXERA

what does Phylloxera do?

A
  • insect feeds on and lays eggs on roots of grape vines
  • weakens roots, causing swelling and cracks which leads to rot
  • spreads through crawling or flying - usually via humans on roots, soil, equipment, irrigation systems
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35
Q

PHYLLOXERA

What are the symptoms of phylloxera?

A
  • vines die of drought and patches increase year on year
  • roots are covered with insects surrounded by yellow eggs
  • swellings on older roots
  • pale green leaf galls on under-surface of leaves
  • slow, stunted shoot growth and leaf yellowing appears around 3 years, and then plant dies after about 5 years
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36
Q

PHYLLOXERA

When was Phylloxera introduced/identified?

A
  • 1863

- destroyed 2/3rds vineyards in late 19th Century

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37
Q

PHYLLOXERA

What are the management options for Phylloxera?

A
  • use of american rootstocks which form seals around the wounds which prevent invasion by bacteria or fungi. Need to be paired with European vines as rootstocks don’t give pleasant wine!
  • 3 american rootstock varieties:
    • v. berlandieri
    • v. riparia
    • v. rupestris
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38
Q

PHYLLOXERA

What are the issues associated with using american rootstocks?

A
  • issues on calcerous soils. Can cause chlorosis
  • have created rootstock hybrids between american species so as to balance protection and resistance to lime in soil
  • american rootstocks which were developed could deal with a number of problems (phylloxera, nematodes, extreme soil pH, water stress, salinity) as well as can control vine vigour
  • today a vineyard would get tailored advice on choice of rootstock and grape variety to match to their vineyard
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39
Q

NEMATODES

What are nematodes?

A
  • tiny worms found in soils
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40
Q

NEMATODES

What issues do nematodes cause?

A
  • feed off vine roots, reducing yield and vigour
  • cause slow decline of vine
  • can transmit viral diseases (e.g. fanleaf virus)
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41
Q

NEMATODES

What are the two most common nematodes?

A
  • root-knot nematode
  • daggar nematode
  • either found in the soil
    or
  • spread by unclean nursery stock, irrigation or vehicles
  • can never be eliminated - only managed
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42
Q

NEMATODES

What are the management options for nematodes?

A
  • need to take soil samples to lab to determine number and type
  • can leave soil to fallow for number of years (very expensive as no crop!)
  • fumigate soils - have to use chemicals which are mostly banned now
  • plough in cover crop of mustard plant which contains compounds which work as BIOFUMIGANTS, killing the nematodes
  • best solution: nematode resistant rootstocks
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43
Q

GRAPE MOTHS

What issues do grape moths cause?

A
  • can attack at different times
    • flowers in spring
    • grapes later on
  • create wounds which cause more issues later one and can lose a lot of crop
44
Q

GRAPE MOTHS

what are the three most common grape moths?

A
  • light brown apple moth (australia)
  • european grapevine moth (southern europe)
  • grape berry moth (central and eastern north america)
45
Q

GRAPE MOTHS

What are the management options for grape moths

A
  • insecticides
  • biological controls
    * bacterium BACILLUS THURINGIENSIS
    * produces a substance toxic to moths
    * sexual confusion (using pheremone capsules)
    * natural predators (parasitic wasps, green lacewings, some spiders)
46
Q

SPIDER MITES

What issues to spider mites cause?

A
  • most detrimental mite to vines
  • differ from region to region
  • feed on surface cells of leaves which leads to: discolouration,
    reduction in photosynthesis,
    delays in ripening,
    reduces yields
47
Q

SPIDER MITES

What conditions to spider mites thrive in?

A
  • dusty conditions

- especially damaging when vine is water stressed

48
Q

SPIDER MITES

Name 3 types of spider mites

A
  • pacific spider mite (california)
  • red spider mite (europe)
  • two forms of yellow spider mite (europe)
49
Q

SPIDER MITES

What are the management options?

A
  • create an inhospitable environment
    • sprinklers
    • cover crops etc
  • encourage predatory mites that feed on spider mites
  • general pesticides
50
Q

BIRDS

What damage can birds cause?

A
  • can destroy an entire crop as ripening occurs
  • this is especially prevalent if vineyard is isolated and is the only source of food
  • bird damage allows bacteria and fungi to enter bunches which causes rot
  • starlings are biggest risk
51
Q

BIRDS

What are the management options?

A
  • netting (very expensive!) They use this in Mornington Peninsula
  • bird scarers, noises etc. Need to rotate often so don’t become used to them
  • falcons used to deter birds
52
Q

MAMMALS

What problems do mammals cause?

A
  • eats shoots, grapes, leaves
  • break grape skins, which make them vulnerable to rot
  • damage trellising
  • lowers yield
  • lowers quality
  • costs to repair damage
53
Q

MAMMALS

What do the pests include?

A
  • deer
  • rabbit
  • kangaroos
  • racoons
  • wild boar
  • baboons
54
Q

MAMMALS

What are the management options?

A
  • fencing - needs to be high enough and sunk deep enough to stop animals jumping or burrowing
55
Q

Name the 6 pests which can cause issues to grape growing

A
  • phylloxera
  • nematodes
  • spider mites
  • grape moths
  • birds
  • mammals
56
Q

Name the 6 fungal diseases which cause issues to grape growing

A
  • powdery mildew
  • downy mildew
  • grey rot
  • eutypa dieback
  • phomopsis cane and leaf spot
57
Q

POWDERY MILDEW

What fungus causes powdery mildew?

A

ERYSIPHE NECATOR
- aka OIDIUM TUCKERI

  • its grapevine specific but american species are less vulnerable than v. vinifera
  • most widespread vine disease in the world
58
Q

POWDERY MILDEW

What two varieties are most prone to the disease and which two are less prone?

A
  • PRONE: Cab and Chardonnay

- LESS PRONE: Riesling and Pinot Noir

59
Q

POWDERY MILDEW

How does it attack vines?

A
  • overwinters in buds and on canes
  • attacks young green parts of vine - starts dull grey and then becomes black
  • patches damage young shoots, inflorescences and grapes
  • reduces yields
  • can cause grapes to split during veraison and become targets for other infections
60
Q

POWDERY MILDEW

What is the optimum temperature for growth for powdery mildew?

A
  • 25 degrees
  • thrives in the shade
  • doesn’t require high humidity and can spread in dry conditions
61
Q

POWDERY MILDEW

What are the management options?

A
  • OPEN CANOPIES: reduce shade and leaf density
  • SULFUR: helps prevent and treat. Spray from budburst to veraison. Need to spray early to prevent rather than contain
  • SYSTEMIC FUNGICIDES: penetrate green tissue, not washed off by rain. Can become resistant so limit applications
62
Q

DOWNY MILDEW

What is it caused by?

A
  • PERONOSPORA: water mould that lives within vine tissue. Common in most wine regions
  • attacks green parts of plants, especially young leaves and flowers. Reduces yield by defoliating vines
63
Q

DOWNY MILDEW

What does it need to spread?

A
  • rainfall

- warm temps of approx 20 degrees

64
Q

DOWNY MILDEW

What are the symptoms?

A
  • yellow, circular ‘oil spots’

- white, downy fungal growth on underside of leaves

65
Q

DOWNY MILDEW

What are the management options?

A
  • sprays of copper salts e.g. BORDEAUX BLEND - combo of copper sulfate and lime.
    * protection doesn’t last long - only until 20mm rain has fallen
  • fungicides - applied from month after budburst to veraison
  • good drainage and an open canopy
66
Q

GREY ROT

What is it more commonly known as?

A
  • botrytis cinerea
67
Q

GREY ROT

What issues does it cause?

A
  • loss of yield and drop in quality of wine
  • grapes need to be selected out at harvest
  • grapes are very vulnerable if there is a point of entry and whole bunches can be attacked
  • if flowers are affected, fungus can stay dormant until after veraison
68
Q

GREY ROT

What grapes are most at risk?

A
  • grapes with tight bunches or thin skins are most at risk
  • Sauv Blanc
  • Semillon
  • Pinot Noir
69
Q

GREY ROT

When do spores become active?

A
  • in periods of rainfall and high humidity
70
Q

GREY ROT

What are the management options?

A
  • choosing grapes with thick skins and higher resistance
  • protecting grapes from pests
  • keeping the canopy open, removing leaves around bunches
  • fungicides (not copper or sulfur) - apply when flowering nearly complete, end of grape formation, bunch closure and veraison. Not very effective as fungus develops resistance
  • antagonistic bacteria - BACILLUS SUBTILIS - can also use other forms of biological controls
71
Q

EUTYPA DIEBACK

What is it and what does it cause?

A
  • AKA ‘dead arm
  • fungal trunk disease leading to rotten wood in vines
  • reduces yields
  • kills vines over 10 year period if not tackled
72
Q

EUTYPA DIEBACK

How does it spread?

A
  • spores spread by wind over long distances
  • occurs through pruning wounds in moderate temperatures - especially during rain
  • effects are evident in spring as short young shoots come through and yellow leaves
73
Q

EUTYPA DIEBACK

What grape varieties are particularly susceptible?

A
  • grenache
  • cab
  • sauvignon blanc
74
Q

EUTYPA DIEBACK

Which regions are particularly susceptible?

A
  • South Australia
  • SW france
  • California
75
Q

EUTYPA DIEBACK

What are the management options?

A
  • v difficult to control
  • pruning late and applying fungicide to the pruning wounds
  • cut back affected trunks 5-10cm beyond visible symptoms
  • burn dead wood to avoid spreading
  • biological controls - BACILLUS SUBTILIS
  • if badly affected, retrain from sucker (shoot that grows from base of the vine) which would take 2 years, or remove the vine and replant
76
Q

PHOMOPSIS CANE AND LEAF SPOT

What is it and when does it occur?

A
  • fungal disease causing reduction in crops

- prevalent where cool and wet springs are followed by humidity and moderate temperatures

77
Q

PHOMOPSIS CANE AND LEAF SPOT

  • what does it present as?
A
  • canes whiten and break off easily
  • shoots growing from canes develop brown cracks at bases
  • leaves can also be affected
78
Q

PHOMOPSIS CANE AND LEAF SPOT

what grapes are most susceptible?

A
  • grenache

- cab sauv is less affected

79
Q

PHOMOPSIS CANE AND LEAF SPOT

What are the management options?

A
  • fungicide applied three weeks after budburst and every 2 weeks if wet conditions continue
  • diseased wood removed and burned
  • prune early or late, and not when its raining
80
Q

ESCA

What is it?

A
  • complex fungal disease caused by groups of organisms prevalent in warmer/drier climates (e.g. S Europe, California)
  • enters pruning wounds
  • reduces yield of plant and causes it to die
81
Q

ESCA

How does it present?

A
  • tiger striping of leaves

- spotting inside wood

82
Q

ESCA

What are the management options?

A
  • all about disease prevention
  • disease-free stock
  • less detrimental pruning
  • not pruning in the rain
  • removing prunings from vineyard
  • disinfecting pruning wounds
83
Q

What are other possible fungal diseases which need to be considered?

A
  • black rot
  • black-foot disease
  • bot canker
  • anthracnose
84
Q

What two bacterial diseases need to be considered?

A
  • Pierce’s disease

- grapevine yellows

85
Q

PIERCE’S DISEASE

What is it?

A
  • kills vines quickly
  • believed to have american origins as present in California
  • bacterium lives in sap channels of vines causing them to clog, shrivel and drop their leaves
  • vines typically die between 1 and 5 years
86
Q

PIERCE’S DISEASE

How is it spread?

A
  • by a sharpshooter insect (vector)
87
Q

PIERCE’S DISEASE

What are the management options?

A
  • no chemical control so need to test vines in labs
  • need to reduce number of vectors by:
    • removing vines close to rivers as riverbanks harbour vectors
    • chemical insecticides
    • wasps which feed on eggs of sharpshooters
  • strict quarantine on movement of plants
  • development of Pierce’s Disease resistant vines
88
Q

GRAPEVINE YELLOWS

What is it?

A
  • group of diseases cause by type of bacteria

- serious threat as no treatment

89
Q

GRAPEVINE YELLOWS

How is it spread?

A
  • spread by vectors including leafhoppers and by nurseries selling diseased, untreated stock
90
Q

GRAPEVINE YELLOWS

What is it commonly known as in Europe?

A

Flavescence Doree

91
Q

GRAPEVINE YELLOWS

Where else is it commonly found?

A
  • germany
  • france
  • s Europe
  • NY State
  • Australia
92
Q

GRAPEVINE YELLOWS

What are the symptoms?

A
  • delayed budburst
  • drooping posture (new shoots fail to lignify)
  • canopy turning yellow (white varieties) or red (black varieties)
  • vine either dies or can recover after an attack
93
Q

GRAPEVINE YELLOWS

What are the most vulnerable varieties

A
  • Chardonnay

- Riesling

94
Q

GRAPEVINE YELLOWS

What are the management options?

A
  • no control
  • need to control the vector e.g. control the leafhopper with insecticides, removing cover crops etc
  • Nurseries need to bathe pruning wound in hot water to kill disease
95
Q

Name two other bacterial diseases

A
  • bacterial blight

- crown gall

96
Q

Name two viruses which cause issues in the vineyard

A
  • fanleaf virus

- leafroll virus

97
Q

FANLEAF VIRUS

What is it?

A
  • longstanding group of diseases - found around the world
98
Q

FANLEAF VIRUS

What happens to the vine?

A
  • early shoot growth stunted
  • canes distorted
  • pale leaves which are malformed and look like fans
  • can lose most of the crop in some cases
99
Q

FANLEAF VIRUS

How is it spread?

A

mainly spread with DAGGER NEMATODES

  • historically spread on grafted vines using infected plant material
100
Q

FANLEAF VIRUS

What are the management options?

A
  • no cure - infected vine needs to eventually be removed
  • before replanting, need to test the soil for presence of dagger nematodes
  • should only use virus-tested clean planting materials
101
Q

LEAFROLL VIRUS

What is it?

A
  • group of viral diseases widely present around the world
102
Q

LEAFROLL VIRUS

How is it spread?

A
  • spread by grafting

- spread by MEALY BUGS (SA, Mediterranean, Argentina, California)

103
Q

LEAFROLL VIRUS

What does it do?

A
  • doesn’t kill but does reduce yield by half
  • affects quality of grapes
  • slows down growth of roots and shoots
    * can take fruit additional weeks to ripen and have more acidity, less colour and lower sugar levels
  • affect carb stores in vines
104
Q

LEAFROLL VIRUS

When does it usually occur and how does it present?

A
  • in autumn
  • leaves change colour to red (black grapes) or yellow (white grapes)
  • have to lab test vines as can carry virus without showing symptoms
105
Q

LEAFROLL VIRUS

What are the management options?

A
  • no cure
  • only solution is to remove unproductive vines and replant with virus free stock
  • nurseries need to screen for infection
  • open canopies to reduce humid environment

WSET 4 (17 decks)

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