WSET Diploma D1 Hazards, Pests, & Diseases CH8 Flashcards
What are 9 Hazards That Can Occur in a vineyard
Drought Excess of Water Untimely Rainfall Freeze Frosts Hail Sunburn Fire Smoke Taint
How Much water do vines need in cool and warm climates
When does drought occur, what are its negative effects
How can you combat drought through management options
Cool - 500 mm water
Warm - 750 mm water
Lack of water - vine closes stemata to prevent water loss, slows photosynthesis, plant growth impaired, grape size reduced, ripening slows, eventually if long enough vines will die. Prolonged periods even with irrigation can die
Management Options
- Irrigation when allowed, can occur with difficulty after planting
- If new vineyard being planted, drought resistant rootstock should be considered (ex. Vitis Rupestrist & Berlandieri, 100R, 140R)
- Choose drought tolerent variety, ex Garnacha
Excess of Water, how does it occur, what are its negative effects
How can you combat Exccess water through management options
Rainfall, poor draining soils, waterlogging
Excess water can lead to too much vegatative growth, compete with fruit ripening, too much shading, less ripeness.
Rainfall can increase disease pressure due to high humidity
If soils are not free drainingcut off oxygen, eventually killing vine, Waterlogging can compact soils
Management Options
- Plant on slope
- Plant of free draining soil
- Construction of drainage system
Untimely Rainfall, what are its negative effects
How can you combat Untimely Rainfall through management options
- Rainfall suring pollination and fruitset can lead to millerandage or coulor reducing yields and quality
- Rain during summer can reduce ripening fruit
- Mild Water deficience before verasion can be posative for grapes
- Heavy Rainfall close to vintage can swell grapes, splitting them, leading to Grey Rot. Reduce must concentration, making harvest difficult (ex. hard for machines to access on wet clay soils)
Management Options - nothing really
- Choice of site, slope, soil, adaquate drainage
- Monitoring weather forcasts, harvest earlier or later
Freeze, what temp does it occur, what are its negative effects, what part of vine is most at risk
How can you combat Freeze through management options
-20C (-4F)
Prolonged freeze can severly damage or kill vines
The graft most susceptible, then canes and cordons. Can kill them, then need replacing (Canada, Washington, China)
Management options
1) Site Selection
a) Hilside Sites (up to 5C, 9F warmer)
b) Vineyards near large or deep bodies of water, moderating effect, (ex Great Lakes)
c) Vines planted where snow is most thick, provide insulation
2) Choice of Varieties
a) Some varieties more resilient against winter freeze, ex. Cab Franc, Riesling
b) Some American and Mongolian species of vine species, and extremely winter hardy. American concord can survive -30C, -22F
3) Protecting Vines
a) Building up soil around vine graft, insulates vine
b) Burying vines, costly in labour, occurs in China some seeing as one of most costly operations in vineyard
c) Pruned to have several trunks, ones killed in winter replaced
What are Two Types of Frosts, what temp does it occur, what are its negative effects
How can you combat Frost through management options (2 Categories)
When cool air 0C (32F) settles ground level, settles in vine’s growing buds and shoots
Cool winds after budburst, if freeze very bad, reduce yields
If buds and yound shoots are killed, secondary buds, less fruitfullness, longer to ripen
Frosts:
Advective - large volumes of cold air move in from cold areas
Radiative - Heat lost in still, cool nights
Management - 2 Categories
1) Reduce the Risk
a) Site Selection, avoid frost pockets, hillside sites, cold air drains away
b) Delay pruning, postpones budburt into warmer months
c) Late budding varietals, ex. Riesling
d) Vines trained high off ground, cold air low
e) Bare soil inbetween vines, trap day heat, radiate at night
2) Combat the Hazard -
a) Water Spriklers (aspersion),Water freezes around plant, releases latent heat, only one to combat Advective Frost, water is costly
b) Wind Machines, Helecopters do the same, pull warm air down, costly initial investment
c) Oil or Propane Gas Burning Heaters, high fuel and labor cost, low heating efficiency, pollution
What is and When does it Hail, what are its negative effects
How can you combat Hail through management options
Pellets of frozen rain, Severe damage to vines
- Unpredictable (Argentina & Burgundy regular issue)
- Rip young shoots and leaves
- Damage Ripening fruit
- Yields Reduced
- Encourages disease
Management Options
- Rockets fired into thunderclounds (Hail Cannons) with Silver Iodide to cause rainfall
- Netting - creates shading, so only in sunny areas
- Hail can be selective, growers have multiple plots
- Crop insurance against hail
What is and When does Sunburn Occur, what are its negative effects
How can you combat Sunburn through management options
In prolonged hot weather, (higher chance with water water stress) grape transpiration more limited, heats up more than the leaves, burns
Negative effect on quality, usually sorted out, reducing yields. Scars on skin, browning grape, bitter taste, susceptible to rot
Management
- Design new vineyard, row orientation and aspect (ex. Northern Hem plact east west)
- Canopy Management, control shade
- If forcasted, additional irrigation to reduce water stress, avoining sunburn
- Cloth or Net, Agricultural sunscreen spray
What is and When does Fire Occue, what are its negative effects
How can you combat Fire through management options
Serious in hot dry climate, associated with climate change Ex Australia, California, Chile
Hard to detect, smoke taint, lots of fuels
Management
- Fire detectors and sprinklers
- Water tank
- Employee training in event of emergency
What is and When does Smoke Taint Occur, what are its negative effects
How can you combat Smoke Taint through management options
- Smoke in vineyard during growing season
- Smoky or plastic aromas in wine
- Most effected verasion onwards
- Smoke absorbed by graps, bind with sugars, creates aroma-less precurors, then oly aromatic after fermentation
Management Options
- Test affected must by micro vinification, establish extent of problem
- How grapes are handled can reduce effect, hand harvest, gentle whole bunch press, lower fermentation temps, shorter maceration
- Flash Detente and Reverse Osmosis, not removed completely
What Pests/Animals can Threaten Vines and impact production
What do grape growers evaluate
Evaluate seriousness of attack, measures to be taken. Economic cost vs damage
Pests & Animals
- Phylloxera
- Nematodes (Root knot, dagger)
- Grape Moths (Light Brown Apple Moth, Grape Berry Moth, European Grape Moth)
- Spider Mites (Pacific Spider Mite, Red Spider Mite, Yellow Spider Mite)
- Birds
- Mammals
Other Pests
- Leaf Hoppers (direct vine leaf damage)
- Ladybirds
What is Phylloxera, how is it harmful, how does it spread
What symtoms does a vine show
How to combat Phylloxera through management options
Aphid like insect feeds and lays eggs on roots of vines.
Damage roots, make prone to disease and fungi, less uptake of nutrients, weaken, then kill
Transported mainly by humans, in soil, on equipment, irrigation water
Symptoms
- Vines die of drought in patches
- Vine roots surrounded by yellow eggs and insects
- Swelling on older roots
- Pale green leaf galls under leaves
- Slow stunted shoot growth, yellow leaves - in 3 years, vine dies in 5 years
Management options
- Vines in sandy soil immune
- American vine species - Riparia, Berlandieri, Rupestris. Hard corky layers seal wounds, not letting in, unwanted aromas, grafed to European varieties for desired wine
- Create rootstock hybrids to avoid chlorosis turning leaves yellow
- Rootstocks derived form american species
- Professional advice on what to plant and how to combat
What are Nematodes, how is it harmful, how does it spread
What are two common Nematodes
What symtoms does a vine show
How to combat Nematodes through management options
- Microscopic worms, feed on vine roots reducing vigour and yield, others transmit viral disease
Spreads
- Already present in soil, unlean rootstock from nursery, irrigation water, or vehicles, only managed, never eliminated once present
Root Knot Nematodes root feeders
Dagger Neamtodes - viral
Management - soil analyzed for number and type, not much to do
- Fumigate soil (chemical banned in lots of regions), plow in cover crop of mustard plant - contains biofumigants kill nematodes
- Nematode resistant rootstock, Ramsey, Dog Ridge (Vitis Champini)
What are Grape Moths, how is it harmful, how does it spread
What are three most common Grape moths and where are they located
What symtoms does a vine show
How to combat Grape Moths through management options
Moths feed on flowers (spring) and grapes (later in year)
Wounds more susceptible to fungi, bacteria, botrytis, signficant crop lossed can occur.
Inadvertently imported
Light Brown Apple Moth - Australia
European Grape Vine Moth - Southern Europe
Grape Berry Moth - Central & Eastern North America
Management
1) Biological
a) Bacterium, Bacillus Thuringiensis, prduces supstances toxic to moths
b) Sexual Confusion - pheramone capsules to stop mating
c) Natural Predators - parasitic wasps, green lacewings, some spiders
2) Insecticides
What are Spider Mites, how is it harmful, in what conditions do they thrive
What are the Types of Spider mites, where are they from
What symtoms does a vine show
How to combat Spider Mites through management options
Most detrimental of mites
Thrive in dusty conditions, when vines are already water stressed. Feed on surface cells of leaves - reduce photosynthesis, delay ripening, and reduce yields
Pacific Spider Mite - California
Red Spider Mite - Europe
Yellow Spider MIte (2 forms) - Europe
Management
- Inhospitable enviornment, sprinklers, cover crops, mulches to reduce dust
- Encourage Predatory Mites (plant host species)
- Specific sprays, pesticides can kill beneficial mites, can add to cost
