Ch 4 - Viticulture Flashcards
What is the annual growth cycle of the vine, in chronological order?
- Winter dormancy
- Weeping
- Bud Break
- Shoot and leaf growth
- Photosynthesis begins
- Flowering
- Berry set
- Version
- Physiological maturity
- Harvest
Process by which materials are moved from one part of the plant to another
translocation
process by which sunlight is converted to sugar
Photosynthesis
process by which water evaporates through pores on undersides of leaves
transpiration
process by which sugar is broken down and converted into biological energy
respiration
A problem that causes poor fruit set, also known as shatter
Coulure
soil-based roundworm that has increased due to shallow root stock
Nematodes
mold that can be beneficial, also known as noble rot
Botrytis cinerea
a fungal disease known as powdery mildew
Oidium
a problem with fruit set where grape bunches have a high proportion of small seedless berries
Millerandage
a fungal disease known as downy mildew
Peronospora
bacterial disease spread by the glassy-winged sharpshooter
Pierce’s disease
a destructive louse that feeds on roots of vinifera vines
Phylloxera
Difference between climate and weather?
Climate = historical average / what is expected in the long run. Weather = actual meteorological conditions in the short term / what actually happens
How much water do grapevines need annually?
20-30 inches
Why are low fertile soils better for commercial vineyards?
less fertile = less vegetation and fewer grapes - concentrates sugar and phenolics better
Put these soil types in order (from largest to smallest particle size): gravel, silt, clay, sand
- gravel
- sand
- silt
- clay
How would a high elevation vineyard differ from one on a valley floor?
cooler, windier, less fog, more intense sunlight and larger diurnal temperature swings
what effects do bodies of water have on nearby vineyard climates
water changes temperature slower, so it nearby vineyards experience less temperature swings. Diurnal temperature changes are less, summers are not as hot, winters are milder. Humidity can provide fog, as well as greater cloud cover, rain, and dampness.
T/F - in general, lower latitude = warmer climate
true
Where do they use the Oechsle system of measuring grape ripeness?
Germany and Switzerland
Does photosynthesis stop at night?
Yes - can only occur while sun is shining
What ground temperature is needed for bud break?
50 degrees farenheit
For dry table wines, what is the typical time from bud break to harvest
140 to 160 days
In the northern hemisphere, who gets more sun: north-facing or south-facing slopes?
South-facing slopes (opposite is true in Southern Hemisphere)
Do continental climates have hotter summers and colder winters than Mediterranean climates?
yes
what is a Guyot system of vine training?
a simple cane-pruned system where one cane from each vine in a row is trained along a wire, all in the same direction.
What is the conversion factor for degrees Brix to alcohol?
55%
What temperature range is the sweet spot before photosynthesis starts to slow down?
50-90 degrees farenheit
What does a refractometer measure?
grape sugar levels
What is a pergola system of vine training?
Overhead vines are trained up a tall support and then allowed to spread out horizontally
Who regulates biodynamic viticulture in the US?
Demeter International
What is veraison?
grapes begin a sudden acceleration toward maturity and take on color
what are ideal latitudes for grape growing?
30 to 50 degrees (either north or south)
List in order the life cycle of a grape
bud break, shoot and leaf growth, flowering, berry set, version, harvest
