Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Hazards, Pests and Diseases > Hazards > Flashcards

Hazards Flashcards

1
Q

What is the minimum amount of rainfall vines need in cool and warm climates?

A

Cool climates- 500mm
Warm climates- 750mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens to the vine if there is drought?

A

Leaves close their stomata- reduces photosynthesis.
If continues- grape size reduced, ripening slows down= unripe grapes and lower yields.
If prolonged- grapes lose their leaves and die

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the ways of managing drought?

A

Irrigation
Rootstocks- V.berlandier/ v.rupestris parentage. eg 110R/140R.
Drought tolerant varieties eg garnacha

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does an excess of water do?

A

Too much vegetative growth- shades grapes from sun= less ripening and competes for sugars and nutrients
High humidity= fungal disease
Water logging= reducdes ox to roots= death.
Water logging- compaction of soils- hard to work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does one manage an excess of water?

A

Slopes
Free draining soils
Construction of drainage system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens there is freeze?

A

-If temp falls below -20, vines dies.
-If vine grafted onto root stock, graft most at risk.
-Frost can kill cordons/canes= reduced yield and kill whole vine.
Canada, Washington State, China most at risk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How can one manage freeze?

A

1.Site selection
-hillsides can be 5 degrees warmer than valley floor
-near large bodies of water, eg large lakes in North America- moderates temp
-plant vines where snow settles most thickly= deep layer of snow provides insulation
2. Choice of varieties
-cab franc/Riesling
-American and Mongolian varieties do well, or a hybrid of one of these. eg V. amurersis
-eg concord variety
3. Protecting the vines
-burying the vines- costly (China)
-hilling up the vines- soil insulates the vine
-vines can be pruned to have several trunks, so those killed in winter can be replaced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What causes frosts and what does it do?

A

-When cold air below 0 degrees collects at ground level, freezing water in vines growing buds and shoots.
-If happens to newly burst buds/young shoots- kills them
-cool climes vulnerable- vine doesn’t grow until 10 degrees
warm climates vulnerable- vine starts growing- damaged with drop in temp.
If buds and shoots killed, secondary buds= less fruitful and longer to ripen= more likely affected by rain/autumn frosts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are advective frosts?

A

Large vols of cold air moving in from v cold areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is radiactive frosts?

A

-Heat being lost on still, cool nights.
-earth heated by sun during day, radiates during night.
-amount of heat lost depends on cloud cover.
-windless nights= layer of freezing cold air to develop above surface of soil
-cold air dense than cold air- collects in valleys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How can you reduce the risk of frosts?

A

-Site selection- hillsides, avoid frost pockets.
-Delaying pruning- warmer months.
-Late budding varieties- eg riesling
-High training- cold air at ground
-Bare soil between the vines- not cover crops= absorbs heat during day, radiates at night

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can you do when frost threatens?

A

1.Sprinklers- as water freezes around part of vine, releases latent heat, protecting vine. Must be kept on until temp rises.
-Running cost lower than wind/heaters- but not if cost of water high.
-only method to combat advective frost.
2. Wind machines- pull warm air from above down to ground level= raising temp
-effective where inversion layer of air 10m above ground
-initial cost
3. Oil/propane gas.
Disads- cost of labour and fuel, and for environment, not that effective, air pollution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What effect does sunburn have to the grapes?

A

Grape transpiration more limited than leaf transpiration= grapes can reach higher temp= sunburn.
Browning, bitter taste, increased susceptibility to rot (skin damage)
= needs sorting =reduces yields

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How can you manage sunburn?

A
  1. Row orientation and aspect. In n hemisphere, avoid E-W orientation or else southern side gets sunlight all day, and intense in the afternoon.
  2. Irrigation
    3.Canopy management
  3. Agricultural sunscreen/cloth/net
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is most at risk of fires?

A

Cover crops, mulches, woodlands, pastures= fuel to the fire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How can you manage fire risk?

A

Smoke detectors
Employee training
Installing and maintaining water tank

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens to the grapes during smoke taint?

A

-effect on the fruit occurs from veraison onwards
-aroma compounds in smoke absorbed by grapes
-once in the grapes, compounds bind with sugar and aroma less precursors= compounds only become aromatic through ferm process
-strength of aroma can increase during ageing of wine and during bottle ageing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the management options for smoke taint?

A
  1. Affected must test analysis and/or micro-vinification to release smoke aroma in days leading up to harvest- establish extent of problem.
  2. Smoke precursors present in skins= handle carefully.
    -hand harvest
    -whole bunch pressing
    -low ferm temps
    -reduced maceration times
    3.Flash detente, reverse osmosis. = helps but doesn’t remove completely
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are nematodes?

A

Microscopic worms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What damage to nematodes do?

A

Feeding off vine roots- significantly reducing yields and vigour
Transmit viral diseases- eg fanleaf virus spread by nematode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How are nematodes spread?

A

Unclean equipment, irrigation water, machinery
Unclean nursery stock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How can nematodes be managed?

A

Fumigate the soil
Plough mustard cover crops- contains biofumigant- kills nematodes
Rootstocks- Dog ridge and Ramsey
Plants from nurseries need to be heat treated to kill the nematodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What do grape moths do?

A

-Feed on flowers in spring, and grapes later on in year.
=Wounds cause bacteria and fungi- crop loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are some examples of grape moths?

A

Light brown apple moth- Australia
European grapevine moth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How can moths be managed?

A

Insecticides
Pherome tags and capsules- sexual confusion
Bacillus thuringiensis- produces toxic substances to moths
Natural predators - some spiders, green lace wings, parasite wasps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Give examples of spider mites

A

Pacific Spider Mite- California= most destructive
Red and yellow mites- europe= cause damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What do spider mites do?

A

-Feed on cells of leaves
-Discolouration
-Slows down photosynthesis
-Slows down ripening
-Reduces yield
-Thrive in dusty conditions- most damaging when vine already water stressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How to manage spider mites?

A

-Make environment inhospitable- sprinklers, cover crops, mulches= reduces dust
-Encourage predatory mites
-General pesticides= kill beneficial predatory mites, so can use tailored ones- but expensive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is powdery mildew caused by?

A

Fungus called Erysiphe Nectator or commonly known as Oidium Tuckeri

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Which vine species and grapes are more susceptible to powdery mildew?

A

Vitis vinifera.
Cab sav and chard- more susceptible
PN and Riesling- less susceptible

31
Q

What does powdery mildew do to the vine?

A

Overwinters in buds and canes.
Then attacks young green part of cane.
Fungus causes dull grey patches on leaves- turns to black.
Patches damage young shoots, inflorescences and grapes- reducing yield.
Grapes split at veraison= other infections.

32
Q

What does the growth rate of powdery mildew depend on?

A

Temperature. Optimum temp- 25 degrees and likes shady areas.
Doesn’t need humidity, can spread in dry conditions, especially dense canopies.

33
Q

How can you manage powdery mildew?

A

Open canopy
Sulphur- spray from a couple of weeks after budburst until veraison.
Systematic fungicides- penetrate green tissue of the vine, doesn’t wash off by rain.
-fungicides can become resistant= only limited number of applications per year.

34
Q

What causes Downy Mildew?

A

Fungus called Peronospora- water mould that lives within vine tissue, not on surface

35
Q

What does Downy Mildew do?

A

Attacks green part of vine, especially young leaves and flowers- reducing yields by defoliating the vine

36
Q

What conditions does downy mildew need?

A

Rainfall and warm temps (20 degrees)
High risk periods- warm springs, warm summers

36
Q

What are the symptoms of downy mildew?

A

Yellow circular oil spots, then white fungal growth on underside of leaves

37
Q

How can you manage downy mildew?

A

1.Sulphur- ‘Boredaux Mixture- copper and lime spray.
-Only works until 20mm of rainfall.
-Only option for organic.
2. Fungicides
3. Good drainage, open canopu

38
Q

What causes grey rot?

A

Botrytis cinerea fungus

39
Q

What does grey rot cause?

A

Loss in yield
Loss in quality (colour, body, aromas/flavours

40
Q

Which grapes are most at risk of grey rot?

A

Thin skins and tight bunches- eg Semillon, Savy B, PN
Grapes vulnerable if any points of entry (grapes rubbed up against each other in tight bunches/punctured by birds/insects
-If flowers affected, fungus can stay dormant in grape and re emerge after veraison

41
Q

What conditions are needed for grey rot?

A

High rainfall and high humidity- sores become active in these conditions

42
Q

How can grey rot be managed?

A

-Choose varieties with thick skins, eg Petit Verdot.
-Open canopy
-Sulphur and cooper sprays don’t work , so other fungicides can be used at key points in season (when flowering nearly complete, end of grape formation, bunch closure and veraison.
-however fungicides can become resilient
-Antagonistic bacteria- bacillus subtilis.

43
Q

What is Eutypa Dieback

A

-‘Deadarm’
-Rotten wood in vines- can affect whole vys.
-reduces vys significantly and kills vines over 10 year period if not tackled.

44
Q

How is Eutypa Dieback spread?

A

Spores spread by wind over long distance

45
Q

How does Eutypa Dieback occur?

A

Pruning in mod temps and especially during rainfall.

46
Q

What are the symptoms of Eutypa dieback?

A

In spring- stunted shoot growth and yellow leaves

47
Q

Give some examples of varieties that are susceptible to Eutypa Dieback, and some areas.

A

Grenache, Cab sav, Savy B
South Australia, SW France, California

48
Q

How can you manage eutpya dieback?

A

-Pruning later
-Applying fungicide to pruning wounds
-Cutting back woof to 5-10cm beyond visible symptoms and treated to fungicides. Dead wood must be burnt to stop spores spreading.
-Bacillus subtilis
-If badly affected, retrain from sucker left on vine, or remove vine and replant.

49
Q

What is Esca caused by?

A

Group of organisms in warmer climates, eg southern Europe, California.
Enters vine through pruning wounds.

50
Q

What are the symptoms of esca?

A

Tiger striping of leaves
Spotting inside of wood.
Reduced yield, and kills within a few years

51
Q

How can you manage esca?

A

-disease free stock
-different pruning techniques
-not pruning in rain
-removing prunings promptly from vy, disinfecting pruning wounds

52
Q

What is Pierce’s disease?

A

-Quickly kills the vine
-Bacterium lives in sap channels of vine, clogs= grapes shrivel
-Dropping leaves
-Death= 1-5 years

53
Q

What are the symptoms of Pierce’s disease?

A

Unclear- needs to be tested in labHow

54
Q

How is Pierce’s disease spread?

A

Sharpshooter insect- vector
-glassy winged sharpshooter= disease spread more rapidly

55
Q

Which varieties are vulnerable to Pierce’s disease?

A

chard and PN

55
Q

What are the management options for Pierce’s disease?

A

-no chemical control
1. reduce vectors- remove vines close to rivers (riverbeds habitat for blue green sharpshooters)
- chemical insecticides
-wasps- feed on eggs of sharpshooter
2. strict quarantine- prevent further spread
3. Pierce’s disease resistant vines

56
Q

What is grapevine yellows and what is it caused by?

A

Group of diseases caused by bacteria

57
Q

What is grapevine yellows spready by?

A

Vector- leafhoppers and nurseries- untreated stock

58
Q

What is the most common type of grapevine yellows in europe?

A

Flavescence doree

59
Q

What are the symptoms of grapevine yellows?

A

-wilted posture- due to shoots not lignifying
-canopy turns yellow for white grapes, red for black
-delayed budburst
-sometimes dies, sometimes recovers

60
Q

Which grapes are the most vulnerable to grapevine yellows?

A

chard and riesling

61
Q

Where can the grapevine yellows bacteria live?

A

In plants like cover crops

62
Q

How can you manage grapevine yellows?

A

-no treatment for bacteria
-reduce vectors- insecticides
-remove cover crops- habitat for bacteria and vectors
- in nursery- bathe pruning wood in hot water= kills

63
Q

What is the outcome for vines infected with grapevine yellows?

A

Reduced yield and quality (high acidity and low sugar)

64
Q

What happens to the vine with fanleaf virus?

A

-stunted shoot growth
-canes become distorted
-leaves become v pale and malformed, go into fan shape

65
Q

What affect does fanleaf virus have on vineyard?

A

Sometimes little effect, sometimes ruins whole crop- cab sab v susceptible

66
Q

How is fanleaf virus spread?

A

Spread enormously through grafting after phylloxera
Also spread by Dagger Nematode

67
Q

How can you manage fanleaf virus?

A

-No cure- need to remove and replant vines
-Before vy replanted- need to test soil- no dagger nematodes and only virus tested, clean planting material used

68
Q

How is the leafroll virus spread?

A

Grating and mealy bugs.
Argentina, Mediterranean, South Africa

69
Q

What effect does the leafroll virus have?

A

Doesn’t kill- reduces yield up to half, and bad grape quality

70
Q

What does the leafroll virus do?

A

-slows down ripening of roots and shoots
-surviving fruit- delayed ripening, low sugar, high acid, less colour
-overall health of vine affected- stores less carbs
-downward rolling of leaves in autumn
-leaves turn red for black grapes, yellow for white

71
Q

How can you manage leafroll virus?

A

-no cure- remove, replant
-control mealybugs- prefer humid environments, canopy management
-encourage predators, lady bugs, lacewings
-nurseries can screen vines for virus infections

72
Q
A

Hazards, Pests and Diseases (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions