Viticulture Flashcards
How can spider mites be managed?
- sprinklers or cover crops to reduce dust
- predatory mites
- pesticides
What is the optimal temperature for germination?
79 - 90 degrees F
How is leafroll virus spread?
Unclean grafting and mealybugs
What is the optimal temperature range for photosynthesis?
64 - 91 degrees F
What causes downy mildew (peronospersa)?
- water mold living in vine tissue
- warm springs and rainy, warm summers
What is the optimal temperature for vine flowering?
63 degrees F
Describe Esca?
- complex fungal disease caused by a group of organisms
- favors warm, dry climates
- enters through pruning wounds
- tiger striping on leaves
- reduces yield, kills in a few years
What are the symptoms of Pierce’s Disease?
- bacteria clogs sap channels
- shrivels grapes
- drops leaves
- kills between 1 to 5 years
What are the symptoms of grapevine yellows?
- delayed budburst
- droopy shoots
- failure of shoots to lignify
- leaves turn yellow or red
How is Fanleaf virus transmitted?
nematodes
How is Pierce’s disease spread?
Glassy winged sharpshooter
How does Eutypa dieback attack a vine?
through pruning wounds
How is oidium best managed?
- keep open canopy
- sulfur treatments
What are the visual symptoms of downy mildew?
- oil spots and white downy growth on leaves
- defoliation
What are the symptoms if powdery mildew?
- dull grey or black patches on leaves
- reduces yield
How are grapevine yellows spread
insects
How is Pierce’s Disease managed?
- no cure but insecticides may help
- remove vine from insect habitats
- predatory wasps
- quarantine exposed plants
How is leafroll virus managed?
- no cure, remove vine
- screen for virus in nurseries
- reduce mealybug populations via open canopies and predatory insects
Leafroll and Fanleaf are what type of diseases?
viral
What are the visual symptoms of phylloexera?
- insect eggs on vine roots
- pale galls on leaves
- stunted growth
- yellow leaves
- vine death
How is downy mildew managed?
- open canopy
- good drainage
- Bordeaux mixture (copper sulfate and lime)
What is the most common grapevine yellow disease?
Flavescence doree
What are the symptoms of fanleaf virus?
- stunted growth
- distorted canes
- pale, deformed leaves
What are 2 synonyms for gobelet training?
- albarello
- en vaso
- bush training
What are the symptoms of leafroll virus?
- reduces yield and quality
- slows growth of roots and shoots
- slows ripening
- more acidic grapes with less color and sugar
- downward turned red or yellow leaves
What is the minimum amount if sunshine hours needed to support viticulture?
1300 hours
What type of pruning is easiest for mechanization?
spur pruned
What is the optimal temperature range for the synthesis of anthocyanins?
59 - 77 degrees F
What ester is responsible for banana aromas?
isoamyl acetate
What is the primary role of magnesium?
- found in chlorophyll and necessary for photosynthesis
How much rainfall per year does a vine need?
- 19 inches in cool regions
- 29 inches in warm regions
What causes chlorosis?
low iron levels in high pH soils
What are the 2 types of frost?
- advective
- radiative
What are the 2 types of buds?
- compound buds form in one growing season and open in the next
- prompt buds form and break in the same growing season
Dagger and root knot are types of what?
nematodes
What is the effect of too much nitrogen?
Excessive canopy growth
What is the main role of nitrogen?
Needed in proteins and chlorophyll for photosynthesis
What is the effect of under cropping?
- sugar deficit in grapes
- too many leaves create too much shade
What is the effect of too little potassium?
inhibits sugar accumulation in grapes
What is the effect of too little phosphorus?
poor root systems
What rootstocks are considered nematode resistant?
- Ramsey
- Dog Ridge
The uptake of what key nutrient is inhibited in low pH soils?
phosphorus
What does the Huglin Index take into account?
- mean and max temps
- day length at altitude
What is the effect of too little magnesium?
- poor yields
- poor ripening
What are the visual symptoms of Dead Arm?
- stunted shoot growth
- yellow leaves
What are common methods of must concentration?
- reverse osmosis
- vacuum extraction
- cryoextraction
During which development stage does chlorophyll begin to break down and anthocyanins synthesize?
Veraison
What is the primary role of potassium?
Regulates water flow in vines
What is the main symptom of phopmosis?
Canes turn white and become brittle
How is phopmosis managed?
- improve air flow in canopy
- burn dead wood
- fungicide
What is the role of roots in vine development?
- anchor vine
- uptake water and nutrients
- store carbohydrates
- produce growth hormones
What two methods of vine propagation do not involve planting from seeds?
- cutting (grafting)
- layering
What effect does water stress have on photosynthesis?
Will cause vine to conserve water by halting transpiration. This prevents CO2 from entering, halting photosynthesis
What is the effect of too little nitrogen?
- low vigor
- yellow leaves
- can impact fermentation
What is the primary role pf phosphorus?
needed for photosynthesis
What is the main benefit of light colored soil?
reflects radiation onto vines
What is the primary role of calcium?
supports the structure of the plant
What are the most important elements which develop in early grape growth?
- accumulation of tartaric and malic acid
- tannin accumulation
- development of aroma compounds
What are the best way to control the spread of grapevine yellows?
- control insect populations
- bathe pruning wood in boiling water to sterilize
Silver iodide is used as a precaution against what?
Hail
In what conditions does oidium thrive?
- shade
- 77 degrees F
- doesn’t require high humidity
During what stage of development would you expect to find the highest levels of malic acid?
Veraison
How are head trained vines able to be pruned?
- spur
- replacement cane
What is the result of over cropping?
too high yields cause grapes to take from carb reserves
What defines a maritime climate?
- low difference between summer and winter temps
- evenly spread rainfall
What defines a Mediterranean climate?
- low difference between summer and winter temps
- rainy summers
- drier winters
What is the optimum age range for a vine to produce fruit?
10 - 40 years
What is the main benefit of dark colored soils?
Absorbs and releases heat at night
What are the 4 most important species of American rootstock?
V Labrusca
V Riparia
V Berlandieri
V Rupestris
Describe transpiration
- stomata on underside of leaves allow water to diffuse out as CO2 enters
- this forces vine to take up water and nutrients from the soil
Describe millerandage
high percentage of seedless, green, unripe grapes caused by cold, wind, and wet during fruit set
Why do sloped vineyards absorb more sunlight?
solar radiation hits earth at an angle
What are the 4 main features of organic viticulture?
- compost application
- cover crops
- natural fertilizers
- reduction of monoculture
How is “growing degree days” defined?
heat summation during growing season
How are nematodes combatted?
- soil fumigation
- mustard plants
- resistant rootstock
- buy treated rootstock from nurseries
What is the purpose of summer pruning?
- enhance ripeness
- reduce fungal pressure
- ease of management
At what temperature does a vine emerge from dormancy?
50 degrees F
What is aspersion?
coating vine with ice to prevent frost damage
Describe coulure
High percentage of fruit set failure caused by imbalance in carbohydrate levels due to low photosynthesis or high water stress
How can grape moths be controlled?
- bacilius thuringiensis
- sexual confusion
- natural predators (wasps, spiders)
Replacement cane training is also known as what?
Guyot
What causes low carbohydrate levels?
- excessive leaf removal
- water stress
- mildew infections
- excessive yield in previous season
How are cordon trained vines usually pruned?
Spur pruned
How is grey rot managed?
- plant thick skinned varieties
- prevent wounds from other pests
- open, dry canopies
- fungicide
- antagonistic bacteria
Why can west facing vineyards encounter problems?
They can get too much strong afternoon sun
What is the most commonly grown grape in the world?
Caberbet Sauv
What is Tephra?
fragmented materials that get ejected from volcanoes
What is the effect of too much potassium?
- inhibit magnesium uptake
- high pH in soils
What does “weeping” or “bleeding” refer to in regards to a vine? When does this occur? Before what stage in the vine’s life cycle does this occur? What average air temperature triggers this?
refers to the running of watery sap from pruned canes sometime in February (Northern Hemisphere)/August (Southern Hemisphere) when a vine emerges from dormancy
Occurs prior to bud break when average air temperature surpasses 50F
What hazard is the vine most vulnerable to during bud break?
Frost
What stage follows budbreak? How many weeks afterwards does this happen? What happens during this stage?
Flowering; embryo bunches bloom into small flowers for about 10 days, and the self-pollinating grapevine begins the process of fertilization, leading up to fruit set.
This occurs 5-12 weeks after bud break
What are the 3 main hazards to a vine during the flowering stage?
damaging effects of cold, frost, and wind
What stage follows flowering? What happens during this stage?
Fruit set; successfully pollinated embryo bunches grow into true grape clusters during fruit set- each grape is the product of individual fertilization.
What % of embryos successfully fertilize during fruit set to produce grapes on the cluster? What happens to the rest?
around 30%; the rest “shatter” falling from the cluster
What treatment can be applied to low pH soils to raise the pH?
Lime/wood ash
What species of American vine’s rootstock was the major contributor to phylloxera resistance?
Vitis riparia
What attributes are considered when selecting a rootstock?
resistance to phylloxera
ability to withstand other diseases and drought
tolerance to salt and lime
its effect on vine vigor
What are the two methods of vine training? How do they differ at the basic level? Which requires a trellising system?
Head training and cordon training
In cordon training, the vine has at least one permanent cane that extends from the trunk, called an arm or cordon. it grows thick and gnarled over time, and fruit-bearing shoots will emerge from it each season.
Head-trained vines have no permanent cordon, and the trunk ends in a knob or head.
Cordon-trained vines require a trellising system. Head-trained vines rarely require trellising as they’re self-sustaining by nature and don’t need an apparatus such as a tree, stake, or wire trellis to stand upright.
What is an example of a head-training method that requires a trellis?
Guyot
How many spurs does a cane-pruned vine have? How many canes grow during the growing season? How many are retained following the season? What type of vine training uses cane-pruning?
One permanent spur
Two canes grow from the spur, one of which was retained form the previous pruning and contains the buds from which the shoots will emerge.
The newly grown cane will be retained and will be the source of the following year’s clusters. The 2 year old cane will be removed.
Head-trained vines use vine pruning.
What type of vine training system uses spur-pruning only? Which type of training system can be either?
Cordon-trained vines are spur pruned only
Head-trained vines can be cane or spur pruned
Cordon de Royat is an example of what training and pruning combo? Where is this system commonly used?
Cordon-trained/spur-pruned
Commonly used in Champagne for Pinot Noir
What are three examples of spur-pruned/cordon-trained vine systems?
Cordon de Royat
Geneva
Lyre
If a vine is trained using the Tendone system, how does it grow? How is it pruned? What is the purpose of this? What is this system called in Italy? What is this system called in Portugal?
Grows upward and overhead along wooden frames or trees. Can be either spur-pruned or cane-pruned.
Trained so that workers to pass underneath. Also promotes good circulation and protection from frost.
Called Pergola in Italy and Enforcado in Portugal
Who introduced the principles of biodynamic farming in 1924?
Rudolph Steiner
What is the average growing season temperature required to ripen white and red grapes?
white - 66 degrees f
red - 70 degrees f
What is the term for the stem of a vine’s fruit cluster?
rachis
What is the Ravaz index?
measurement used to establish vine balance
What is the term for the grafted portion of a vine above ground?
scion
60% of grape loss across the world is due to what disease?
Leafroll
What is another name for daktulosphaira vitifoliae?
phylloxera
What species of grapevine is wild and self pollinating?
Vitus sylvestris
What is the French term for harvest?
vendage
What producer markets his dead arm vines?
d’Arrenberg
What is the name for the waxy coating on the outside of grapes and what is its role?
Bloom
- protects from disease
- prevents dehydration
- collects yeast and beneficial microbes
What is another name for Esca?
Black Measles
What is the French term for budbreak?
debourment
List 2 biodynamic certifying bodies
- Demeter
- Biodyvin
What type of soil is basic? What type of soil is acidic?
Limestone - basic
non limestone - acidic
How many meters in elevation cause a 1 degree drop in temperature?
100 m
What rootstock is know to be late ripening?
rupestris
What are the 6 biodynamic compost preparations?
- yarrow (502)
- chamomile (503)
- stinging nettle (504)
- oak bark (505)
- dandelion (506)
- valerian (507)
What are the 3 biodynamic spray preparations?
- horn manure (500)
- horn silica/ground quartz crystals (501)
- Horsetail tea (508)
