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Hazards, Pests and Diseases > Hazards, Pests, Diseases > Flashcards

Hazards, Pests, Diseases Flashcards

1
Q

Describe the effects of DROUGHT
(Initial effect/impact on vine, short term effects, prolonged drought effects)
Give example of affected region

A

Lack of water causes vine to close stomata on leaves in order to limit water loss. This reduces Photosynthesis. Leads to impaired plant growth, reduced grape size and slowed ripening.
Results in potentially unripe grapes, lower yields.
If prolonged, vines will lose leaves and die.
Region - Olifants River region of SA.

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2
Q

Specify management options for DROUGHT

  • Vineyard design
  • Variety
  • Rootstock
A

Irrigation systems should be considered as part of initial design of vineyard (where allowed). Later addition can disrupt vineyard due to laying of pipes etc.

When choosing a rootstock - drought-resistance on list of priorities. e.g. V. Rupestris and V. Berlandieri parentage (110R and 140R)

Choose drought tolerant variety i.e. GARNACHA

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3
Q

In what “emergency cases” do some EU appellations allow irrigation (DROUGHT)

A

Establishing young vines

Drought that threatens the livelihood of growers

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4
Q

Describe the effects of EXCESS OF WATER

Effect in summer, to vines, to roots, to vineyard

A

Summer - too much vegetative growth, can compete with grape ripening and also fruit is shaded = less ripeness

Can make canopy prone to fungal diseases due to high humidity

Waterlogging may occur in soils not free-draining, reducing amount of oxygen available to the roots = slows down growth and eventually can kill vine
Can also lead to compaction of soils = difficult to work, and uncontrolled water run-off

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5
Q

Specify management options for EXCESS OF WATER

A

If excess on a regular basis, planning of the vineyard must address this issue by, where possible-

Planting on a slope or on free-draining soil

Construction of drainage system

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6
Q

Describe the effects of UNTIMELY RAINFALL

  • during pollination and fruit set
  • during the summer
  • close to vintage
A

-P&FS - can lead to MILLERANDAGE and COULURE = reducing size of crop and potentially lowering quality
-Summer - can reduce the rate of ripening fruit
-Close to V - heavy rainfall can lead to
>grapes being swollen with water = reducing must concentration and therefore quality of wine
>grapes splitting = leading to grey rot.

Makes working harvest very difficult = using mechanical harvesters, pickers accessing vineyards if on clay soil

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7
Q

Specify management options for UNTIMELY RAINFALL

A

Choice of site (climate in general, slope), condition of soil, whether or not to grass the land in between rows of vines, adequacy of drainage

Monitoring weather forecasts - winemakers may have to weigh up options of early harvest = potentially less-ripe fruit, taking chance of weather improving = potentially losing all or part of the crop

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8
Q

Describe the effects of FREEZE

  • Temperature danger zones
  • Risks to parts of vine
  • Areas most affected
A
  • 20°C can cause serious damage to vines, or even kill
  • 25°C kills vine

If grafted onto a rootstock, the graft is the most at risk part (if above ground)

Canes and cordons next at risk - frost can kill canes and cordons (reducing yield) - or all parts of vine above ground = leading to need to replace vine

Areas with strongly continental climate e.g. parts of Canada, Washington State, China

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9
Q

Specify management options for FREEZE re SITE SELECTION

A

Areas with very cold winters, growers have several options -

  • Hillside sites can be up to 5°C warmer than valley floor
  • Near large or deep bodies of water benefit from moderating effect (i.e. large lakes in North America)
  • Vines planted where snow settles more thickly = deep layer of snow can provide insulation
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10
Q

Specify management options for FREEZE re variety/rootstocks

A

Choose variety more resilient against winter freeze e.g. Cabernet Franc, Riesling

Some American and Mongolian vine species (V. AMURENSIS) = winter hardy, as are hybrids with these as parent
E.G. CONCORD VARIETY (american hybrid) can withstand temps down to nearly -30°C

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11
Q

Specify management options for FREEZE re protecting vines

A

Building up soil around the vine graft - “hilling up” - helps to insulate vine

Burying vines - in extreme climates. Very costly, requires a lot of labour - costliest vineyard ops in some chinese regions

Vines can be pruned to have several trunks - those killed can be replaced

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12
Q

What are PESTS?

A

Organisms that harm the vine and impact the production of grapes in a negative way.

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13
Q

Describe the effect PHYLLOXERA has on the vine. Explain how it is spread

A

Aphid-like insect - feeds and lays eggs on the roots of grapevines. Can spread through crawling, most commonly transported by humans eg on roots of young vines, in soil, on equipment such as leaf trimmers or harvesters, by irrigation water

They damage the roots - reducing the uptake of nutrients and water. Damaged roots are then also vulnerable to attack by bacteria and fungi.
Attacks lead first to a weakening of plants (reducing growth and yield) and then to the death of the vines

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14
Q

Describe 5 symptoms of vineyards with PHYLLOXERA infestation

A
  • Vines die of drought in patches that increase in size YOY
  • Vine roots are covered with the insects surrounded by yellow eggs
  • Swellings on older roots
  • Pale green leaf galls on the under-surface of the leaves
  • Slow, stunted shoot growth and leaf yellowing appears in around 3 years, the plant dies after around 5 years
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15
Q

Identify management options for PHYLLOXERA (with reasons) -

A

Vineyards on sandy soil are immune to Phylloxera

  • Use of american vine rootstocks, graft european varieties on - V. Berlandieri, V. Rupestris, V. Riparia offer most protection. They form hard, corky layers that surround the eggs, sealing the wounds and preventing invasion by bacteria or fungi.
  • Planting on rootstocks is significantly more expensive than on the vines own roots, but has become a standard part of the cost of establishing a vineyard
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16
Q

(PHYLLOXERA) What was the risk identified from grafting onto rootstocks of single american varieties? Solution?

A

-these varieties have little lime tolerance (problematic in typically calcerous soils of Europe) - vines suffered from chlorosis turning leaves yellow, halting photosynthesis, reducing yields and quality.

Create rootstock hybrids between various american species in order to balance the level of protection to phylloxera and resistance to lime in the soil

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17
Q

What are NEMATODES, and describe the effect they have on the vine and how they can be spread

A

Microscopic worms - very common in soils, too small to be seen by the naked eye

Some cause damage by feeding off the roots, significantly reducing yields and vigour

Can cause slow, gradual decline

Some transmit viral diseases - e.g. FANLEAF virus is spread by dagger nematode

Either present in the soil or can be spread by unclean nursery stock, irrigation water, vehicles

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18
Q

Which are the 2 most commonly occurring NEMATODES?

A

Root-knot nematode

Dagger nematode

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19
Q

Identify management options for NEMATODES.

A

Fumigate the soil - chemicals are banned in most regions
Plough in a cover crop of mustard plant - contains compounds that work as biofumigants, killing nematodes

Best solution is the use of nematode resistant rootstocks having ensured that plants bought from nurseries have been heat-treated to kill them.

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20
Q

Give 2 examples of NEMATODE-resistent root stocks

A 
RAMSEY (V. Champini)
DOG RIDGE (V. Champini)
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21
Q

How do GRAPE MOTHS affect the vines?

A

Feed on flowers and grapes - several generations per season - flowers in Spring, Grapes later in the year

Wounds created are then vulnerable to further attack - bacteria, fungi - e.g. botrytis - significant crop loss

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22
Q

What are the 3 most common types of GRAPE MOTH?

A

Light brown apple moth (Australia)

European grapevine moth (Southern Europe)

Grape berry moth (Central and Eastern North America)

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23
Q

Describe management options for GRAPE MOTHS

A

Biological controls

  • Bacillus thuringiensis (bacterium) produces substances that are toxic to the moths
  • Pheromone capsules to disrupt mating (sexual confusion)
  • Natural predators (parasitic wasps, green lacewings, some spider species)

Insecticides can be used

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24
Q

Describe the effects of FROST on a vineyard

A

Frosts occur when cold air below 0°C collects at ground level, freezing water in growing buds and shoots

Cold winds blowing across vineyard after budburst also dangerous - if freeze happens to new burst buds or young shoots with high water content, it kills them

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25
Q

What happens if bud and young shoots are killed from FROST

A

Vine puts out secondary buds - however these shoots are less fruitful and will take longer to ripen - more likely affected by rain and/or autumn frost

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26
Q

What are the 2 types of FROST?

A

Advective frosts - caused by large volumes of cold air moving in from very cold areas

Radiative frosts - the result of heat being lost on still, cool nights.Earth is heated by the sun during the day and releases it during the night. Amount of heat lost depends on amount of cloud cover. Windless nights allow a layer of freezing cold air to develop just above the surface of the soil. Collects in valley bottoms

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27
Q

What are the management options to REDUCE THE RISK of FROST

A
  • avoid frost pockets (when picking location) - choose hillside sites where air can drain away
  • Delaying pruning delays budburst into warmer months. Frosted buds at the end of canes can be removed
  • Choose a variety that buds late - e.g. Riesling
  • Vines trained high - coolest air is near the ground
  • Bare soil between vines - absorbs more heat during the day, radiates at night
28
Q

What are the management options WHEN FROST THREATENS

A
  • Sprinklers - As water freezes around the plant, it releases latent heat, protecting the plant - costs can be lower than heaters and wind machines, but not if the cost for water is high. Only method to combat ADVECTIVE frosts
  • Wind machines - 4-7m high, pull warmer air from above, down to ground level. Effective where an inversion layer (warm zone of air 10m above ground (+3-5°C). Cost warranted if risk of damaging radiation frost once every 5 years. Helicopters same effect.
  • Oil or propane gas heaters, wax candles - high cost of fuel and labour, low heating efficiency and contrib. to air pollution
29
Q

Describe the effect of HAIL on the vineyard

Give examples of regions

A

Hailstones can damage and rip young shoots and leaves

Ripening grapes can be damaged/become a point of entry for botrytis and other diseases

Yields can be seriously reduced (both in that and following seasons)

If early on in the season, the vine may be able to reshoot from existing buds

Argentina and Burgundy suffer repeatedly

30
Q

Describe MANAGEMENT OPTIONS for HAIL

A

Rockets into thunderclouds - silver iodide - cause rain rather than hail

Net the fruit zone (common hail areas) to protect ripening. Can only be used where high sunlight levels, as netting creates shade

High-risk areas - Growers may seek to have number of plots in different areas - spread risk

Additional cost of crop insurance

31
Q

Describe the effect of SUNBURN

A

Grape transpiration is much more limited, therefore less effective than leaf transpiration - therefore can reach higher temps than the leaves and become sunburnt

Higher risk in vines already in water stress

Scars on the skin - extreme cases, death of grape

Potential issues - browning of grape, bitter taste, increased susceptibility to rot

Need to be removed by sorting = reduces yields

32
Q

Specify MANAGEMENT OPTIONS for SUNBURN

A

Vineyard design - row orientation and aspect. e.g. NH East-west row orientation should be avoided so that grapes on south side of row are not subject to day-long sun (intense afternoon sunshine)

Direct sun exposure can be adjusted through canopy management techniques. e.g. shading fruit

Heatwave forecasted - additional irrigation may be applied to reduce water stress (therefore sunburn) (where allowed)

Special agricultural sunscreen spray / shade with cloth or net

33
Q

What is the minimum amount of water/rainfall needed per year for vines in cool and warm regions?

A

500mm and 750mm in warm climates

34
Q

Name 3 regions which have been affected by FIRE in recent years?

A

CHILE
CALIFORNIA
PARTS OF AUSTRALIA

35
Q

FIRES spread less easily through ______ , _______ soils.

A

Bare

Cultivated

36
Q

What is the major issue to wine quality with regard to FIRE, and describe

A

Smoke taint - can result in “smoky” or “plastic” aromas in the final wine.
Effect on fruit increases in the period from version onwards.
Aroma compounds in smoke can be absorbed by the grapes - often bind with sugars and form aroma-less precursors - only become aromatic through the fermentation process

The strength of the aroma can increase during ageing and during bottle ageing as further aroma precursors break down and become aromatic

37
Q

Specify MANAGEMENT OPTIONS with regard to FIRE

A

Installing fire detectors and sprinklers

Installing and maintaining a water tank

Provide employee training for action in the event of an emergency

38
Q

Specify MANAGEMENT OPTIONS for SMOKE TAINT

A

Affected musts can be tested analytically and/or by micro-vilifications (to release the smoke aromas) in the days leading up to harvest, to establish the extent of the problem (and therefore what action is needed)

Thought that the aroma-precursors are present on the inside of the skin, how grapes are handled can reduce the effect of smoke taint (Hand-harvesting, gentle or whole bunch pressing, lower fermentation temps, reduced maceration times) (reduce the uptake of the compounds)

Flash detente and reverse osmosis can help, won’t remove taint completely

Can also blend with unaffected wines

39
Q

What is flash detente

A

Designed to extract high levels of anthocyanins and flavours quickly

Destemmed grapes are quickly heated to 85-90°C and then rapidly cooled under a vacuum

The process bursts the cells in the grape skins, allowing rapid extraction of anthocyanins and flavours

Takes place in as little as 2 minutes

Expensive to buy, tends to be used at high-volume wineries

40
Q

Describe SPIDER MITES and the effect they have on the vines/vineyard

A

Spider mites are the most detrimental mites

Pacific spider mite - California
Red Spider mite - Europe
(2 forms of) Yellow spider mite - Europe

They feed on the surface cells of the leaves - leads to discolouration, reduction in photosynthesis, delayed ripening, reduction in yields.

Thrive in dusty conditions, most damaging when vines are already water stressed

41
Q

Specify MANAGEMENT OPTIONS for Spider Mites

A

Inhospitable environment - water sprinklers and/or cover crops or mulches to reduce dust

Encourage predatory mites (by planting host species) that feed on spider mites

General pesticides may kill beneficial predatory mites - specific sprays can be applied to kill only the problematic mites, but this can add to costs

42
Q

Name 2 other insect pests and the damage they do

A

Leafhoppers - direct damage to vine leaves

Ladybirds - cause taints in the wine if they are in amongst harvested grapes

43
Q

What risk to BIRDS have on the vineyard

and what are a common species that attack vineyards

A

In nature, vines rely on birds to spread seeds.

Can destroy entire crops of grapes - especially isolated vineyards that provide the only source of food in the area are particularly in danger

Bird damage allows bacteria and fungi to enter bunches - leads to rot

Starlings one species often attack

44
Q

What are MANAGEMENT OPTIONS for BIRDS

A

cost of total netting can be justified in high risk areas or high value areas (e.g. Mornington Peninsula)

Bird scarers, noises - need to be rotated regularly to avoid getting used to them

Falcons sometimes used to deter unwanted bird visitors

45
Q

What risk do MAMMALS have on the vineyard

A

Damaging structures such as trellising

eating shoots, grapes, leaves

breaking skins of grapes = more susceptible to rot

Reduce Yield, lower quality and extra cost for repairing damage

46
Q

MANAGEMENT OPTIONS for MAMMALS

A

Can be kept out by Fencing - high and sunk into soil (stop burrowing animals)

47
Q

What is the effect of POWDERY MILDEW

+ susceptible varieties

A

Overwinters in buds and on canes
Attacks young, green parts of the vine

Affected parts = dull grey patches —> advance as black patches

Can damage young shoots, inflorescences and grapes - reduce yield

Grapes can split at version and become target for other infections

Thrives in shady conditions, optimum temp 25deg, spreads in dense, shady canopies

Caused by fungus Erysiphe necator (aka Oidium tuckeri)

American species are less vulnerable than V. Vinifera

Chardonnay and Cabernet Sauvignon (less prone Riesling and Pinot Noir)

48
Q

MANAGEMENT OPTIONS - powdery mildew

A

open canopy = reduce shade and leaf density

sulfur applications - help to prevent and treat. Spray early - disease is easier to prevent than contain

Systemic fungicides penetrate green tissue and therefore not washed off by rain. Limited number of applications as fungus can become resistent

49
Q

What is DOWNY MILDEW and describe effects, what it needs etc

A

CAUSED BY peronospora = water mould that lives within vine tissue

HOW IT CAME ABOUT Introduced from NA, now common in most wine regions

WHAT IT NEEDS - Needs rainfall and warm temps (20°C to spread)

EFFECTS ON VINE
Attacks green parts of the plant, especially young leaves and flowers.
REDUCES YIELDS by defoliating vine
(Grapes can be affected but less important)

SYMPTOMS - Yellow, circular “oil spots” and then white, downy fungal growth on the underside of the leaves

RISK ENVIRONMENT/PERIOD - Warm springs, stormy but warm summers

50
Q

What does defoliate mean?

A

Strip/remove leaves from a tree, plant, area of land

51
Q

MANAGEMENT OPTIONS for Downy Mildew

A

SPRAY/CHEMICAL - Sprays made from copper salts
“Bordeaux mixture” = Copper Sulfate and lime
(only organic option, risk of copper build up in soils and water, EU to reduce and ultimately eliminate use)

Other fungicides can be used

VINEYARD - Good drainage, open canopy that dries quickly - avoid development and spread

52
Q

What is GREY ROT and describe effects, what it needs etc

A

FUNGAL DISEASE

CAUSED BY - Botrytis Cinerea - fungus that can cause significant damage to fruit

WHAT IT NEEDS - Spores typically present in the vineyard, active in periods of rainfall and high humidity

EFFECTS ON VINE - Loss of yield, drop of quality in wine (colour, body, aroma/flavour)
If flowers are affected, fungus can stay dormant and re-emerge after veraison

RISK ENVIRONMENT/PERIOD - Vulnerable if points of entry - grapes rubbing together in tight bunches, damaged by birds.
Tight bunches/thin skins - Pinot Noir, Semillon, Sauvignon Blanc

53
Q

MANAGEMENT OPTIONS for Grey Rot

A

VARIETY - select grape varieties that have small grapes with thick skins (e.g. Petit verdot) = high level of resistance

PESTS - Protect against pests that could damage the grapes

VINEYARD - open canopy, better airflow, reduced risk of spread

SPRAY/CHEMICAL - Fungicides can be used - apply at key points in season - flowering nearly complete, end of grape formation, bunch closure, veraison. FUNGUS CAN BECOME RESISTENT. do not overspray

Antagonistic Bacteria - bacillus subtilis - biological control

54
Q

What is EUTYPA DIEBACK and describe effects, what it needs etc

A

AKA Dead arm

WHAT IT IS - Fungal Trunk Disease

HOW IT CAME ABOUT - Spores spread by wind over long distances.

WHAT IT NEEDS - Occurs when pruning wounds in moderate temps and especially during rain

EFFECTS ON VINE - Evident in spring, stunted shoot growth, yellow leaves

Leads to rotten wood in vines, reduces yields significantly, kills vines over 10 year period (if not tackled)

WHERE - Prevalent in South Australia, SW France, parts of California

55
Q

MANAGEMENT OPTIONS for Eutypa Dieback

A

SPRAY/CHEMICAL- Pruning late and applying fungicide to pruning wounds can be effective

VINEYARD - Affected trunks cut back to 5-10 cm beyond visible symptoms, treat with fungicide.
Dead wood must be burnt to avoid spores spreading

Badly affected - Retrain from sucker - loss of yield for 2 years
Remove vine and replant

BIOLOGICAL CONTROLS - e.g. bacillus subtilis - may be effective

56
Q

What is PHOMOPSIS CANE AND LEAF SPOT and describe effects, what it needs etc

A

WHAT IT IS - Fungal Disease

EFFECTS ON VINE - Reduction in Yield
Infected canes whiten and break off easily
Shoots growing from these canes develop brown cracks at bases
Leaves affected

WHAT IT NEEDS - Prevalent in years of cool and wet springs followed by humidity and moderate temps

SUSCEPTIBLE VARIETIES - Grenache
(Less prone, Cabernet Sauvignon)

57
Q

MANAGEMENT OPTIONS for PHOMOPSIS CANE AND LEAF SPOT

A

SPRAY/CHEMICAL - Fungicides should be applied 3 weeks after budburst, every 2 weeks if wet conditions continue

VINEYARD - Diseased and dead wood should be removed during pruning and the removed wood burnt and buried
Canopy management techniques that improve air flow, may reduce risk of disease

58
Q

What is ESCA and describe effects, what it needs etc

A

WHAT IT IS - Complex Fungal disease - group or organisms

WHAT IT NEEDS - warmer, drier climates - Southern europe, California

SYMPTOMS - Tiger-striping of leaves, spotting inside the wood

EFFECTS ON VINE - Enters through pruning wounds.
Reduces yield of plant, leads to death within a few years

59
Q

MANAGEMENT OPTIONS for ESCA

A

NO CHEMICAL CONTROLS

PREVENTION - Sourcing disease-free stock

  • new, less detrimental, pruning techniques
  • not pruning in the RAIN
  • disinfecting pruning wounds
  • removing prunings promptly from vineyard
60
Q

What is PIERCE’S DISEASE and describe effects, what it needs etc

A

WHAT IT IS - Bacterial disease

ORIGINATED - American continent - initially affected southern USA and central america, is PRESENT in california

EFFECTS ON VINE - Kills vines quickly.
Bacterium lives in sap channels of vines = clogs = grape shrivelling, dropping leaves, death of vine 1-5 years

SYMPTOMS UNCLEAR - has to be analysed in a lab

HOW IT’S SPREAD - Vector - sharpshooter
Grassy-winged sharpshooter - leader

SUSCEPTIBLE VARIETIES - Pinot Noir and Chardonnay

61
Q

MANAGEMENT OPTIONS for PIERCE’S DISEASE

A

SPRAY/CHEMICAL - NO CHEMICAL CONTROL FOR BACTERIUM. Chemical insecticides can also be used (for the sharpshooters)

VINEYARD - Reducing number of vector - removing vines close to rivers has been effective - riverbanks can be a habitat for the blue-green sharpshooter
Strict quarantine rules for movement of plants - prevent further spread

PEST - Species of wasp that feeds on the eggs of sharpshooters

FUTURE - work being done on developing Pierce’s disease-resistant vines

62
Q

What is GRAPEVINE YELLOWS and describe effects, what it needs etc

A

WHAT IT IS - Group of diseases caused by a type of bacteria. Serious threat - no treatment available

HOW IT’S SPREAD - by vectors = leafhoppers
nursery selling untreated, diseased stock
Lives in cover crops and other plants.

EUROPE - Flavescence doree. Present in Germany, south Europe, New York State, Australia (different form)

SYMPTOMS - Delayed budburst, drooping posture (new shoots fail to become woody), canopy turning yellow (white varieties) or red (black varieties)

EFFECTS ON VINE - Some strains, vine dies as disease progresses - in others, can recover after attack
Drastically reduced yields, lower quality (high acid, low sugar content)

SUSCEPTIBLE VARIETIES - Riesling and Chardonnay

63
Q

MANAGEMENT OPTIONS for GRAPEVINE YELLOWS

A

No control against the bacteria

CONTROL VECTOR
Insecticides
Plants that host should be removed

NURSERY - Bathe pruning wood in hot water to kill disease

64
Q

What is FANLEAF VIRUS and describe effects, what it needs etc

A

WHAT IT IS - Long-standing group of diseases AKA Fanleaf degeneration

HOW IT’S SPREAD - Was spread by the move to grafted vines (following phylloxera) and use of infected plant material
Spread slower by dagger nematode

EFFECTS ON VINE - Early shoot growth stunted, canes can grown in distorted ways and leaves are very pale, malformed and can look like a fan
Little effect to losing most of crop (in susceptible varieties such as cabernet sauvignon)

65
Q

MANAGEMENT OPTIONS for FANLEAF VIRUS

A

NO CURE - eventually, affected vines will have to be removed and replaced - ADDS TO COST

Before replanting, soil tests should be done for presence of dagger nematodes - VIRUS-TESTED, CLEAN PLANTING MATERIAL should be used

66
Q

What is LEAFROLL VIRUS and describe effects, what it needs etc

A

WHAT IT IS - group of viral diseases present around the world

HOW IT’S SPREAD - Was spread by grafting and mealy bugs - key pest in SA, Med, Argentina and some parts of Cali

EFFECTS ON VINE - Doesn’t kill vines - can reduce yields up to half and affect quality negatively.
Slows down growth of roots and shoots
Surviving fruit may take additional weeks to ripen - have more acidity, less colour and lower sugar levels.
Overall health of vine affected = stores less carbohydrate

SYMPTOMS - Downward rolling of vines leaves - usually AUTUMN. Leaves change colour to yellow/red (white/black varieties)

Vines need to be tested in lab. Some show no symptoms

67
Q

MANAGEMENT OPTIONS for LEAFROLL VIRUS

A

NO CURE - remove unproductive vines and replant with virus-free stock

Nurseries can screen for virus infections

VINEYARD - Mealy bugs favour humid environments - open canopies help reduce
Control by spraying is difficult because of waxy coating

NATURAL PREDATORS - Ladybugs, lacewings, others

Hazards, Pests and Diseases (1 decks)

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