Pancyprian TS Org. Viticulture flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Coulure

Poor fruit set caused by failed fertilization, leaving many empty positions in the cluster and reducing yield; often linked to cold, wet weather at flowering or vine stress.

Millerandage

Uneven berry size within a cluster caused by partial fertilization; small seedless berries ripen unevenly and reduce quality and uniformity at harvest.

Veraison

The ripening transition when berries soften and change colour; sugars accumulate, acids decline, and anthocyanins form in red cultivars.

Ravaz index

Ratio of crop weight to pruning weight, used to assess vine balance; moderate values indicate balanced vegetative and reproductive growth.

VSP system

Vertical shoot positioning; a trellis system where shoots are trained upward in a narrow canopy to improve light exposure and airflow.

Guyot pruning

Cane pruning system retaining one or two long fruiting canes and a renewal spur; suited to cultivars with infertile basal buds.

Spur pruning

Pruning that leaves short two- to three-bud spurs on permanent cordons; simple and mechanizable but can crowd buds over years.

Growing degree days

Accumulated heat above a base temperature, commonly 10 °C, from budbreak to harvest; used to classify cultivar suitability by site.

Winkler index

Climate classification based on growing degree days above 10 °C, dividing regions into five warmth categories from cool to very hot.

Radiation frost

Frost forming on clear, calm nights when heat radiates from soil and vines; site selection, fans and sprinklers can mitigate it.

Advective frost

Frost caused by movement of a cold air mass into the vineyard; wind machines and sprinklers are less effective than for radiation frost.

Cation exchange capacity

Soil's capacity to hold exchangeable cations such as calcium, magnesium and potassium; it influences nutrient retention and fertilizer management.

Active lime

The fine fraction of calcium carbonate in soil that is readily reactive; high levels can induce iron chlorosis in susceptible rootstocks.

Iron chlorosis

Yellowing of young leaves from iron deficiency, common on calcareous soils with high pH; corrected by tolerant rootstocks or chelated iron.

Phylloxera

A root-feeding aphid-like insect that damages Vitis vinifera roots; controlled by grafting onto resistant American rootstock species.

Downy mildew

Fungal disease causing oil spots on leaves and white sporulation underneath; spread by rain splash and controlled with protectant fungicides.

Powdery mildew

Fungal disease producing white powdery growth on leaves and berries; it does not require free water and needs sulfur or systemic fungicides.

Botrytis bunch rot

Grey mould caused by Botrytis cinerea; favoured by humid canopies and wounded berries, reducing quality and yield.

FRAC groups

Classification of fungicides by mode of action; rotating groups reduces the risk of resistance developing in pathogen populations.

Integrated pest management

A decision framework combining prevention, monitoring, thresholds and biological control, using chemicals only when justified.

Regulated deficit irrigation

Irrigation strategy that imposes controlled water stress at specific growth stages to limit vigour and berry size while maintaining quality.

Stem water potential

A vine water status measure indicating tension in the xylem; more negative values indicate greater water stress and guide irrigation scheduling.

Petiole analysis

Laboratory test of leaf petioles at bloom or veraison to diagnose nutrient status and guide fertilizer applications.

Fertigation

Application of dissolved fertilizers through the drip irrigation system, allowing precise nutrient delivery with irrigation water.

Brix

A measure of soluble solids, mainly sugars, in grape must; it is used to estimate ripeness and potential alcohol.

Titratable acidity

Total acids in must measured by titration to a pH endpoint; it reflects freshness and balance alongside pH and sugar.

Potential alcohol

Estimated alcohol from must sugar, commonly about 0.55 to 0.60 percent alcohol per degree Brix, depending on conversion factor.

Mechanical harvest

Harvest using shaking machines that detach berries or clusters; fast and cost-effective but less selective than hand picking.

Pre-harvest interval

The minimum time between the last pesticide application and harvest; it must be respected to keep residues within legal limits.

Re-entry interval

The period after a pesticide application during which workers may not enter the treated area without required protective equipment.

Must clarification

Removal of suspended solids from grape juice before fermentation; it influences aroma, clarity and fermentation kinetics.

Break-even yield

The crop yield per hectare at which revenue equals total costs; it guides planting, pricing and contract decisions.