Glossary of Grape Terms



Abiotic natural control: Control of pests by the action of nonliving factors (for example, high temperature).

Abscission layer: Layer of thin-walled cells along which cell separation (abscission) occurs, to bring about the shedding of plant parts such as leaves, flowers or fruits.

Absorption: A process in which one substance permeates or is taken up by another; a fluid permeates or is dissolved by a liquid or solid.

Acclimation: The natural process of becoming adapted to cold temperature.

Acid soil: Soil with a pH value less than 7.0.

Acropetal: Developing, maturing, or opening in succession from the base to the apex; thus, the oldest parts of the plant are at the bottom and the youngest part are at the top; sometimes used to indicate direction of movement, from base to apex; opposite of basipetal.

Active ingredient: Chemical or chemicals in a prepared product responsible for the desired effects (generally pest control), commonly abbreviated as a.i.

Adsorption: The adhesion of a gas, liquid, or dissolved substance to the surface or interface zone of another substance. If any compound, solid, liquid, or gas is loosely held by weak attraction to the surface of a solid it is said to have undergone adsorption. This process is much weaker and less permanent than absorption.

Adjuvant: An ingredient added to a solution that increases or modifies the action of the principal ingredient. For example, crop oil concentrate may be added to herbicide to enhance its effectiveness. Also see surfactant.

Adventitious bud: A bud in an unusual place on a plant, such as an internode, that is often the result of an injury. Suckers and water sprouts are examples.

Adventitious roots: Root growing from an unusual place, e.g., from a stem.

Aerial root: Root developing adventitiously from the above-ground portion of a vine.After-ripening: The seed maturation process that must be completed before germination can occur.

Aging: The period of time that a wine spends maturing to achieve its best flavor and aroma. Wines are aged in a variety of ways from large casks (such as oak or stainless steel) to bottles. Complex wines tend to benefit from aging, whereas simple wines should be drunk when they are young.

Aisle: The walking space between plant rows.

Alkaline soil: Clay soils with pH above 9.0, poor soil structure and a low infiltration capacity.

American grape: Grapes native to North America. Include mustang grapes (Vitis mustangensis), muscadines and Scuppernongs (V. rotundifolia), fox grapes and Concords (V. labrusca), and riverbank or frost grapes (V. riparia), among others. American grapes are resistant to the phylloxera root louse.

Ampelography: The botanical field in which grapevine varieties are identified, generally by using characteristics such as leaf morphology and berry color.

Anion: A negatively charged ion, (e.g., Cl-, O–).

Anther: The part of the stamen that contains pollen.

Anthesis: The time of flowering or flower opening. Anthocyanin: Water-soluble pigments that may appear red, purple, violet, or blue. Gives red grapes and wines their color.

Aoutement: French term for the lignification (hardening) of young twigs into woody plants. Usually takes place in August.

Apex: 1. The highest point or topmost shoot of the plant. 2. Blossom end of the berry.

Apical dominance: The suppression of lateral (side) branches by the apical (topmost) shoot, or apex, of the plant.

Apical meristem: The region of actively dividing cells at the tip (apex) of a growing stem or root.

Arm: Wood that is two or more years old; short branches of the trunk from which canes or spurs develop.

Aroma: The smell of a wine. The term is generally applied to younger wines, while the term bouquet is used for more aged wines.

Asexual propagation: The creation of new plants by using a vegetative part of the plant such as a leaf, stem, or root – any part other than a seed. Examples include layering, cuttings, tissue culture, and division.

Astringency: A lip-puckering sensation caused by excess tannins, which may disappear as the wine ages.

Available water: The amount of water held in the soil that can be extracted by plants. Also, the difference in the amount of water contained in soil at field capacity and the amount at the permanent wilting point.

Avenue: A space at the end of vine rows, usually 20 to 30 ft in width, wide enough for easy turning of vineyard equipment.

Axil: Where a branch joins the stem.

Axillary bud: Bud formed in the leaf axil, i.e. where the petiole joins the shoot.


Bacterium: One-celled organism that reproduces by fission; several bacteria are pests of grapevines (e.g. Pierce’s disease).

Balanced pruning: Pruning to manage the vegetative and reproductive growth of a grape vine for best fruit quality and vine health.

Bark, plant: Tough, protective covering of the woody stems of trees, shrubs, and vines.

Basal: Located at the base of a plant or stem, especially arising directly from a root or rootstock.

Basal bud: The bud(s) that develop at the base of a shoot, closest to the cordon; they are often non-fruiting in Vitis vinifera but can be quite fruitful in hybrid varieties.Basipetal: In a downward direction from the apex toward the base of a shoot or cane, opposite of acropetal.

Berry: (1) the kernel of certain grains such as wheat; (2) small, juicy fruits that grow on vines and bushes (3) Botanically,a berry is a fleshy fruit produced from a single ovary, such as a grape. The seeds are usually embedded in the flesh of the ovary. Definitions 1 and 2 from LABENSKY, SARAH R.; HAUSE, ALAN M.; LABENSKY, STEVEN R.; MARTEL, PRICILLA, ON COOKING: A TEXTBOOK OF CULINARY FUNDAMENTALS, 4th Edition, ©2007. Electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, New Jersey. Definition 3 from Wikipedia. See berry.

Berry set: The period after bloom (anthesis) when most of the unpollinated flowers have dropped and the pistils of pollinated flowers begin to develop into berries.

Biological control: Control of pest organisms using living organisms or their products (usually introduced) as predators, parasites, or pathogens of the pest.

Bilateral cordon: Extensions of the trunk in the form of two permanent horizontal branches each supported by a wire, extending in opposite directions and from which fruiting positions originate. Examples are high cordon, with downward shoot orientation, and low cordon, with vertical shoot positioning.

Bleeding: The sap exudate that is released from a woody plant after pruning usually occurring near the end of the dormant season.

Blending: A blending cultivar is one grown specifically to be blended with other wine grapes in the winery.

Blight: A sudden, severe or extensive discoloration, wilting or destruction of any plant parts or entire plants, often coupled with the name of the affected part of the host, e.g. leaf blight, shoot blight.

Blind buds: Nodes on spurs or canes from which there is no bud development in spring.

Bloom: 1. The time of flowering as indicated by shedding of calyptras, also known as flower caps. 2. The waxy coating on the surface of a berry that gives a lighter appearance to a dark-colored cultivar.

Botrytis: Botrytis bunch rot or gray mold is a fungal disease that infects fruits and occasionally shoots and leaves; caused by Botrytis cinerea. The benevolent form is known as “noble rot” and is responsible for some of the world's finest sweet wines.

Brix: A measure of soluble solids content in grapes, mostly as sucrose, using a refractometer and expressed in degrees. Each degree of Brix equals 1 gram of sugar per 100 grams of grape juice. Brix is measured at harvest. Most table wines are harvested between 19 degrees and 25 degrees Brix.

Broadleaf: Having broad and flat leaves rather than needle-like or grass-like leaves.

Brush: The broken ends of vascular bundles that remain attached to the pedicel when a berry is pulled off of a cluster, or the prunings left in a vine row.

Bud: An organ on a plant stem consisting of overlapping immature leaves or petals within protective scales. In viticulture, a dormant bud contains a larger primary bud and two smaller secondary buds.

Budburst: Systemic development of grape buds retained at pruning in response to warm spring weather.

Budding: The act of grafting buds of a candidate vine onto an existing vine; usually the grafting of a scion (fruiting) variety onto a rootstock, referred to as “field budding”.

Bud scales: Protective coverings over buds.

Bud sport: A genetic mutation from a bud that results in a distinct difference from the mother plant that can be retained by vegetative propagation.

Bud stick: A short portion of a shoot or cane used as source of buds for budding.


Calcareous soil: Soil with a pH over 7.0 that contains calcium carbonate (lime).Callus: A mass of undifferentiated cells, often resulting from a wound.

Calyptra: The hood or cap covering the calyx.

Calyx: The collective term for all the sepals.

Cambium: The layer of cells between the inner bark and the wood (the xylem and phloem) of a tree, vine, or shrub. It is responsible for secondary growth (new wood and bark cells). The cambium lies just beneath the bark.

Cane: A mature shoot after leaf fall.

Cane training: The process of conforming seasonal vine growth to a desired structure.

Canker: A localized necrotic area of a branch or trunk, usually caused by a fungal pathogen.

Canopy: The foliage of a crop; said to be closed when plant growth of adjacent rows closes over and shades row middles; direct sunlight penetration between rows constitutes an open canopy.

Canopy management: The assessment and resulting action of manipulating shoots, leaves, and fruit for the betterment of vine and fruit quality.

Cap fall: The time of flowering or flower opening. Also known as anthesis.

Cap stem: A small stem that attaches the individual grape berries to the cluster; also called a pedicel.

Capacity: 1. The ability to repay a loan from present income. 2. As applied to grapevines, the total growth and crop that a vine is capable of producing in one year.

Carboy: A glass container, usually holding five gallons, used in the fermentation and storage of wines.

Catch wire: A part of the vertical shoot positioning training system that is used for shoot growth placement.

Cation: Cations are positively charged ions (e.g., Na+, Ca++, K+). Anions are negatively charged ions (e.g., Cl-, O–).

Causal agent: Organism or agent that produces a given disease.

Certified planting stock: Vines that have been identified as true-to-type and disease- and insect-free.

Chaptalizing: The addition of sugar to the must or juice before fermentation to make up for deficiencies in vine-ripened sugar levels.

Chilling requirement: Minimum period of cold weather needed for a fruit-bearing tree or grapevine to flower.

Chlorophyll: Green pigments found in all green plants. Chlorophyll makes it possible for plants to make their own food.

Chlorosis: A condition where leaves turn light green or yellow due to a lack of chlorophyll. This condition can be an indicator of disease, nutrient deficiency, or lack of sunlight.

Clone: 1. A group of plants, growing in close association, derived by asexual reproduction from a single parent plant. Such plants are therefore of the same genetic constitution. 2. Genetically identical plants, usually obtained from asexual propagation methods. First definition from: Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.

Cluster: An entire bunch of grape berries.

Cluster stem: The structure that attaches the entire grape cluster (bunch) to the cane; also called a peduncle.

Cluster thinning: The act of removing fruit to enhance the quality of retained fruit.

Cold stabilization: A winemaking process where wine is chilled to near freezing temperatures for several weeks to encourage the precipitation of tartrate crystals and other insoluble solids, thus clarifying the wine. This procedure is usually used only for white wines.

Compatibility, graft: The ability of a scion and rootstock to join and grow.

Compost: Decomposed plant materials used as fertilizer or soil additive.

Contact herbicide: An herbicide that kills primarily by contact with plant tissue rather than as a result of translocation; also called non-systemic. Only the portions of the plant which came into contact with the herbicide will be affected.

Contact insecticide: Chemical that kills insects as they touch it or as the chemical touches them. Contrast with systemic.

Cordon: A long arm, usually trained along a wire, from which fruiting canes develop.

Corolla: All the petals of a flower.

Coulure: The failure of proper cluster formation after flowering, usually caused by adverse environmental conditions but also by poor management. The vine's grape bunches remain partially formed, thus adversely affecting yield. Pronounced coo-LYUR. Also sometimes called shatter.

Count bud: Any dormant node on a spur or cane retained at pruning, not including basal buds; the first count node is separated by 0.25 inch or more from the basal bud(s) below it, although transitional forms may make it difficult to determine the first count bud.

Cover crop: Crop grown primarily to provide ground cover, prevent erosion, control weeds, or to improve soil properties, rather than provide a harvestable yield. Nearly any crop can be used as a cover crop, but some are more useful than others. For example, legumes such as clover and alfalfa can improve soil fertility.

Crawler: Immature development stage of an insect which has legs and the ability to move; in later stages it may become permanently affixed to one site; usually refers to the first growth stage of an insect.

Cross, plant: A hybrid.

Crown, plant: The point at which the vine stem or trunk meet the roots at or just below the soil line.

Crown suckering: The act of removing shoots at the base of the plant, in order to facilitate improved fruit size and fruit quality in retained fruit, as well as to reduce vine stress.

Cultivar: Derived from cultvated variety. A named variety selected within a plant species. Distinguished by any morphological, physiological, cytological, or chemical characteristics. A variety of plant produced and maintained by cultivation which is genetically retained through subsequent generations. From: Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.

Cultivation: The process of turning over the soil to eliminate weeds or prepare the ground for crops; also called tillage.

Cultural control: Production practices which make the habitat or environment unfavorable for a pest and/or favorable for its natural enemies.

Curtain: A collection of shoots that form a dense canopy, most often used in relation to high cordon trained vines.

Cuticle: The outer layer of living tissue, especially a protective, waxy layer covering the epidermis of a plant.

Cutting: A portion of a dormant cane usually 14-18 inches long used for vegetative propagation: may also refer to a green or herbaceous shoot section to be propagated under mist in a greenhouse.


Deciduous: In general, dropping off, but usually referring to plants that lose their leaves in the fall.

Defoliation: The loss of leaves from a plant, whether naturally (in autumn) or via herbicide, disease or insects.

Degree day: The amount of heat that accumulates over a 24-hour period when the temperature is between the lower and upper development threshold for an organism.

Dentate: Toothed, specifically referring to the teeth on the margin (edge) of a leaf.

Diagnostic: Distinctive, as of a distinguishing characteristic serving to identify or determine the presence of a disease or other condition.

Diatomaceous earth: Very soft, chalk-like rock containing fossilized, single-celled, ocean phytoplankton (diatoms). Diatomaceous earth acts by 1) absorbing the oil or wax from the surface of an insect's body, or 2) creating abrasive damage to the insect's body; in both modes of action the insect loses the thin waterproof epicuticle layer, desiccates and dies. Used primarily in sustainable and organic production systems as a general insecticide. Often abbreviated DE.

Dioecious: A condition in which staminate (male) or pistillate (female) flowers are borne on different plants. Some wild American grapes are dioecious, with male plants unable to produce fruit. See also monoecious. Pronounced die-EE-shus.

Disbudding: Removal of buds, especially from propagation material.

Distal: The end opposite the point of attachment.

Dormancy: Temporary cessation of growth, especially during winter.

Dormant pruning: Pruning during the dormant season.


Economic injury level: Pest population or damage level that will cause economic injury to the crop, the level where grower intervention or treatment is usually recommended.

ELISA: Acronym for Enzyme-linked immunosorbant assay. A test that can be used to confirm the presence of specific proteins signifying the presence of certain pathogens.

Emasculation: Removal of male reproductive structures. In plants, this means removing stamens, anthers, and pollen.

Embryo rescue: The process in plant breeding whereby tissue from young embryo plants is extracted (excised) and propagated in vitro (in glass) for subsequent growth.

Engustment: In grapes, the stage of ripening when aroma and flavor become apparent.

Enology: The study of wine and wine production.

Epidemic: A temporary prevalence of a disease in a locality where the disease is not permanently widespread.

Epidermis: Outermost layer of cells of young plant parts; on roots, some cells differentiate into root hairs, on stems and leaves into hairs of various kinds (pubescence) and on leaves, stems and berries into stomata.

Eradicant: A chemical that eliminates a pathogen from an area or host.

Eradication: To destroy or remove a pest or pathogen after disease.

Eutypa dieback: A severe fungal disease of pruning wounds in grapevine and other woody plants that slowly kills spurs, arms and cordons.

Evapotranspiration: The actual total loss of water by evaporation from soil, water bodies, and transpiration from vegetation, over a given area with time. From: Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.

Exocarp: The outer layer of the pericarp of a fruit. It forms the skin of a grape or peach.Eye: A compound winter bud, consisting of a primary bud and one or more secondary buds.


Fasciation: A distortion of a plant caused by an injury or infection that results in thin, flattened, and sometimes curved shoots and flower scapes, often with several scapes fused side by side.

Fertilization: 1. Addition of fertilizers or nutrients to promote plant growth, either from synthetic or natural sources. 2. In the process of fruit set, the union of sperm cells from the pollen tube with the egg cells of the ovary.

Field grafting: The process of clonally propagating vines in situ.

Field heat: The heat contained in a crop immediately after harvest. Field heat is a combination of the heat absorbed by the plant tissues from the environment prior to harvest and the heat resulting from the relatively rapid respiration occurring in the still-warm plant tissues.

Filament: 1. The stalk of a stamen. 2. A very slender fiber or thread; fibril.

Filamentous: 1. Thread-like. 2. Possessing filaments.

Filtering: Passing through a filter.

Fining: The process where a substance (fining agent) is added to wine to create an adsorbent, enzymatic or ionic bond with the suspended particles, making them a larger molecule that can precipitate out of the wine more easily and quickly. Unlike filtration, which removes particulates such as dead yeast cells and grape fragments, fining is effective in removing soluble substances such as polymerized tannins, coloring phenols and proteins.

Floral differentiation: Flower in inflorescence development after initiation.

Flower cap: Top of the individual flowers that come off during flowering.

Foliar feeding: Technique whereby liquid fertilizer is applied to and taken up by plant leaves.

Foundation stock: A collection of plant materials rigorously tested for freedom from viruses and other deleterious diseases, and verified as true to type (cultivar); these planting materials are provided to certified nurseries who multiply and propagate them for growers.

French-American hybrids: Hybrids of European (Vitis vinifera) and American grapes.

Fruit set: A developmental stage following flower fertilization that marks the beginning of fruit development and maturation.

Fruitful bud: A retained bud that will produce harvestable fruit.Fruiting cane: The one-year-old canes that will produce the current year's fruit.

Fruiting wood: The one-year-old canes that will produce the current year’s fruit.

Fruiting zone: The region of the shoot within the canopy where fruit will hang.

Fumigant: A substance that forms toxic vapors that kills pests.

Fungicide: A pesticide used to control or kill fungi.


Gall: Abnormal swelling of plant tissue caused by insects, microorganisms or injury.

Generation, insect: From any given stage in an insect’s life cycle to the same stage in offspring.

Genotype: Actual genetic makeup of an individual determined by its genes or germ plasm.

Genus: The division of classification up from species and below family; the first name in a binomial (e.g., Vitis in Vitis vinifera).

Gibberellins, gibberellic acid (GA): Plant hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, and sex expression.

Girdling: Girdling involves removing a complete ring of outer and inner bark, extending in depth to the cambium, usually on a trunk and resulting in a temporary interruption of the downward translocation of metabolites in the phloem. Girdling is a common practice in table grape production. Girdling can also happen accidentally, due to a tie that is too tight during training or from grafting tape.

Glabrous: Lacking plant hairs.

Glaucous: Covered with a whitish waxy substance; also called “bloom”.

Graft, grafting: 1. A small shoot (scion) of one plant inserted into another. 2. The union created by a grafting procedure. 3. The act of grafting.

Graft compatibility: Ability of scion and rootstock to join and grow.

Green manure crop: A cover crop that is plowed under to enrich the soil.

Grow tube: Usually a round, plastic tube that fits around young vines to protect it from predators and to facilitate herbicide applications. Often used for trees and grape vines.

Growing season: Period of active growth.

Growth regulator: A natural or synthetic compound that regulates plant or insect growth.

Growth retardant: A natural or synthetic compound that reduces or stops plant growth.

Guard cells: Specialized crescent-shaped cells that control the opening and closing of stomata in the epidermis. Stomata (or stomates) regulate gas exchange and water loss.

Guttation: The appearance of drops of xylem sap on the tips or edges of leaves of some plants. Although guttation occurs at night, it should not be confused with dew, which condenses from the atmosphere, primarily onto the leaf blade.


Hair, plant: Plant hairs may be present on stems or leaves. They are prolonged epidermal cells; on a grape stem or leaf it may be living or dead, deciduous or persistent; on a root it is short-lived and confined to the absorbing zone, called a “root hair”.

Hardpan: A hardened soil layer in the lower A or in the B horizon caused by cementation of soil particles with organic matter or with materials such as silica, sesquioxides, or calcium carbonate. The hardness does not change appreciably with changes in moisture content, and pieces of the hard layer do not crumble in water. cf. caliche. From: Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.

Hardy: Characteristic of plants that are tolerant of adverse climatic conditions, usually used with reference to cold tolerance.

Harvestability: Subjective comparative rating of ease of machine harvesting, “easy,” “medium” or “hard” referring to the force required to remove fruit.

Head, grapevine: The distal terminus of the trunk.

Headland: Uncultivated land at the end of rows or near a fence, used as turning space for equipment.

Hedging: The trimming of grape shoots, usually by machine, to control growth or to keep vine growth appropriate for a given trellis system.

Herbaceous: 1. Non-woody plant growth. 2. A term often used to describe the flavors in wine or grapes that resemble leafy, or vegetative flavors.

Herbicide: A material used to kill weeds, being either selective, killing only certain plants, or broad spectrum, killing many kinds of plants. In cotton, the material usually is characterized by (1) timing: “PPI” (prior to planting and incorporated), “pre” (prior to plant emergence from soil), and “post” (after plant emergence); or by (2) application type: “broadcast” (applied evenly over an area), “banded” (applied over a portion of the total area), or “directed” (targeted at a specific area), usually toward the base of the cotton plant.

Honeydew: Sugary substance secreted by aphids, mealybugs, and soft scales.

Hormone: A naturally occurring substance which is produced in one part of a plant and translocated to another part where it induces a response.

Host: An animal or plant that provides nourishment or a protected home for another animal, such as a parasite, or a disease organism.

Hot spot: A vineyard area where a pest population is substantially larger than in the balance of the vineyard and is at or near the level to cause economic damage.

Humus: The organic fraction of soil in which decomposition is so far advanced that its original form is not distinguishable. From: Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.

Hybrid: A plant produced from the crossing of genetically dissimilar parents. Sometimes called a cross.

Hydathode: A specialized leaf structure with one or more openings through which water is discharged from the interior of the leaf to its surface.

Hydrometer: A calibrated glass float used to measure the specific gravity (relative density) of liquids. In wine, it is used to measure sugar content (Brix) in grape juice, must, or wine.

Hypha: The threadlike filaments forming the mycelium of a fungus.


Incompatibility: The condition in which two organs fail to unite.

Indexing: Determination of the presence of disease by removing buds or other parts for inoculation of a susceptible indicator plant that exhibits specific symptoms of a transmissible disease.

Indicator plant: Plants that are hypersensitive to a pathogen, such as a virus.Indigenous: Born, growing, or produced naturally (native) in an area, region, or country. cf. endemic. From: Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.

Indoleacetic acid (IAA): Plant hormone (an auxin) that promotes growth, especially elongation of stems and roots, and prevents abscission. Often abbreviated as IAA.

Infection: Infection- Invasion of the body tissues by microbial agents or parasites other than insects.

Infest: To attack as a parasite, or to contaminate as with microorganisms.

Infiltration rate: The rate of movement of water from the soil surface into soil.

Inflorescence: Flowers, flower cluster, or flower group.

Integrated control: Pest control strategy that uses all appropriate methods and techniques (cultural, chemical, and biological) to maintain pest populations below economic injury levels.

Internode: The portion of the main stem between nodes.

Interveinal: Between the main veins on a leaf.

Inoculum: Pathogen or pathogen part that infects plants.

Insect growth regulator: Any class of chemicals that interferes with the ability of insects to proceed to the next stage of their life. Often abbreviated IGR.

Instar: Stage of nymph (e.g., stink bug) or larva (e.g., bollworm) between molts.

Inversion, temperature: The condition on a clear night during which air temperature is coldest near the ground and increases with altitude.


Juicing: Subjective, comparative rating of the amount of juice in a bin of mechanically harvested grapes, with descriptors of “light,” “medium”, or “heavy”; given that some percentage of juice is lost during harvest, light juicing is always preferred.


Lamina: The broad expanded part of a leaf, also “leaf blade”.

Larva: The immature stage of an insect with four distinct metamorphic stages (egg, larva, pupa, and adult). For moths and butterflies, the larval stage is as a caterpillar. Plural larvae.

Latent bud: This bud develops in the leaf axil of the shoot during the growing season, initiating development during late spring. The bud forms the flower and leaf primordia for the shoots that grow in the following season.

Lateral: A branch of a shoot. See also lateral shoot.

Lateral shoot: Side shoot or stem that develops from axillary (side or lateral) buds on the stem of current season's growth. Laterals begin to form in the leaf axil along the shoot after hedging. Shown here are Pinot noir grape shoots.

Layer: Technique to replace a missing vine in an ungrafted vineyard, by means of a long cane from an adjacent vine that is buried in the missing vine position; the buried portion will develop roots and is cut from the mother vine after a year or two.

Leaching: The downward movement of materials in soil by the action of water.

Leaf: Flat, thin, green part of the plant that carries out photosynthesis to produce carbohydrates for plant growth and development.

Leaf blade: Flat, thin part of the leaf. The shape and size of leaf blade varies with cultivar. Also known as the lamina.

Leaf bud: The bud from which leaves, but not flowers, develop. Grapes generally develop compound buds that give rise to shoots that contain flowers.

Leaf scar: The scar left on a stem or twig after a leaf falls off.

Lees: The solid sediments (such as dead yeast, seeds, and pulp) left after fermentation. These will be deposited at the bottom of the fermenting barrel or tank. Different winemaking methods are used to manage the lees.

Legs: Wine that adheres to the side of the glass when it is swirled, and then drips back down into the glass. This effect is associated with wines with higher alcohol content.

Lenticel: Small, round or elliptical, pore-like structures, resembling freckles, on the bark of some woody plants that allow gas exchange between the atmosphere and the interior tissues. In most Vitis species of grapes, lenticels are absent on shoots but present on berries and pedicels. Density of lenticels on berries is low, and they are often filled with cuticular wax as the berries develop. Muscadine grapes (Muscadinia species) are distinguished from Vitisspecies of grapes by the presence of lenticels on shoots.

Lesion: Wound or injury site on vine that develops abnormal tissue.

Life cycle, insect: A complete series of life stages from egg to reproducing adult.

Light saturation: The point at which there is no increase in the photosynthetic rate of the plant. Factors that affect the light saturation point are the quantity of photosynthetically active radiation (PAR) and carbon dioxide.

Lignified: The presence of woody or bark-like tissue on canes or peduncles.

Lime sulfur: Calcium hydroxide and sulfur solution that is used to control pests from fungal pathogens to mites. Generally, lime sulfur is used during dormancy and may be used during the growing season at low concentrations. Temperatures must be below 80 degrees Farenheit. Lime sulfur is corrosive and precautions must be made for worker protection and safety.

Lobe: Sections of a leaf centered on the main veins (five in grapes) and separated by sinuses of varying depths.

Locule: In plants, locule usually refers to a small cavity within the ovary that contains the seeds.

Lyre system: A horizontally divided grape training system with vertical shoot orientation of the two canopies; the name arises from a schematic cross-section of the system resembling a lyre musical instrument.


Macroclimate: The large (global, >300km), general weather trend over time (years) in which an animal or plant exists.

Malolactic fermentation: Winemaking process whereby tart malic acid, which occurs naturally in grape must is converted to milder, softer-tasting lactic acid.

Margin, leaf: The edge of a leaf blade.

Mating disruption: A pest management technique designed to confuse male insects by releasing a synthetic pheromone into the environment, thereby masking the female’s natural pheromone plumes and causing the males to follow “false pheromone trails” at the expense of finding mates.

Maturity: In horticulture, the point at which a fruit or vegetable is fully developed.

Mechanical injury: Wound or injury to a plant by equipment.

Mesoclimate: The regional (<50km), general weather trend over time (years). In viticulture, these areas can include vineyard sites, hillsides, or clusters of vineyards. Smaller than a macroclimate but larger than a microclimate.

Methoxypyrazines: A class of chemical compounds that produces herbaceous odors (e.g,. green bell pepper). In white wine (e.g., Sauvignon blanc), the odors can be desirable. However, in red wines (e.g., Cabernet Sauvignon) high levels of methoxypyrazines are very undesirable.

Microclimate: The local (<1km), general weather trend over time (years). These areas can include a single vineyard, a single plant, or even a leaf or grape cluster.

Microflora: A group of microscopic organisms, such as bacteria, which exist in a specific location (for example, on a leaf surface).

Middle, row: In viticulture, the area between vine rows. Also called middle.

Microfauna: A group of microscopic animals, such as protozoa or nematodes, which exist in a specific location (for example, on a leaf surface).

Micronutrients: the nutrients needed only in small amounts; vitamins and minerals. From: LABENSKY, SARAH R.; HAUSE, ALAN M.; LABENSKY, STEVEN R.; MARTEL, PRICILLA, ON COOKING: A TEXTBOOK OF CULINARY FUNDAMENTALS, 4th Edition, ©2007. Electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, New Jersey.

Millerandage: French term for a condition in which some grapes in a bunch do not develop fully, resulting in different sized berries having different maturity levels. Caused by cold, wet weather during flowering. Produces lower quality wine. Also called shot berries or "hen and chicks".

MOG: Material Other than Grapes, such as leaves, other vine parts and foreign material in a harvested grape load.

Molt: To shed a cuticle or exoskeleton during a growth phase.

Monoecious: A plant with separate male flowers and female flowers occurring on the same plant. Pronounced moan-EE-shus. See also dioecious.

Mouthfeel: The overall sensory perception given by a food’s physical and chemical interactions in the mouth, usually excluding taste and aroma. In the case of wine or juice, mouthfeel combines sensations related to the product’s viscosity as well as sensations related to the product’s chemical properties, such as astringency.

Mulch: (n.) (1) A layer of dead plant material on the soil surface. cf. fresh and humic mulch. (2) An artificial layer of material such as paper or plastic on the soil surface. (v.) Cultural practice of placing rock, straw, asphalt, plastic or other material on the soil's surface as a surface cover. From: Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.

Mummy: Shriveled, black grape left on the stem. Mummies are often the result of disease, and potentially a critical source of disease inoculum the following growing season.

Muscadine: American grape Vitis rotundifolianative to the Southeastern United States from Delaware to the Gulf of Mexico. Also see scuppernong.

Muscat: 1. Group of sweet European grapes (Vitis vinifera) grown for wine, raisins, and table grapes. 2. Wine from muscat grapes.

Must: Freshly pressed grape juice that contains the skins, seeds, and stems of the fruit.

Mustang grapes: American grape (Vitis mustangensis) native to the southern United States, including western Louisiana, Texas, and Oklahoma.

Mutation: Changes in the genetic structure (DNA) of an organism. May occur spontaneously or through radiation, viruses, or mutagenic chemicals. Also see bud sport.

Mycelium: The vegetative part of a fungus consisting of a mass of branching threadlike hyphae or filaments.

Mycorrhizal fungi: Fungi that form a symbiotic association with the roots of a plant.


Nematicide: Any agent, usually a chemical, that kills or inhibits nematodes.

Nematode: Microscopic worm-like animals that live in soil or water, or as parasites in plants and animals.

Necrosis: The death or disintegration of cells or tissues while they are still part of a living organism; in plants usually resulting in a darkening of the affected tissue. Reference: McLean, John A. Glossary. Retrieved 01 July 2010.

Node: A structure, usually along the main stem, from which lateral vegetative and fruiting branches arise.

Nodosity: A root gall formed on the tips of small roots by the feeding of grape phylloxera.

Nouaison: French term for the period immediately after flowering, when fruits first begin to form.

Nymph: Juvenile stage of an insect superficially resembling an adult.


Oak root fungus: A disease caused by the fungus Armillaria mellea that causes destructive root rot of grapevines.

Organic matter: In soil, organic matter consists of plant and animal material that is in the process of decomposing. When it has fully decomposed it is called humus. Humus is important for soil structure because it holds individual mineral particles together in clusters. Ideal soil has a granular, crumbly structure that allows water to drain through it, and allows oxygen and carbon dioxide to move freely between spaces within the soil and the air above.

Ovary, plant: The enlarged lower part of a pistil, enclosing the ovules or young seeds.

Overcropping: Excessive crop on a grapevine which results in ripening being negatively affected, making the crop unsuited for its intended purpose.

Overwinter: To survive the winter period.

Ovicide: A material that kills the eggstage of an organism.

Own-rooted vine: An ungrafted vine, growing on its own adventitious roots.


Parasite: An organism that lives wholly off and often feeds within another organism (called a host); with most insect species, insect parasites usually kill their hosts and are referred to as parasitoids.

Parasitoid: An insect that parasitizes and kills other insects, but are only parasitic in their immature stages, killing their host before emerging as a mature larva or adult.

Parenchyma: The primary tissue of plants, composed of thin-walled cells that remain capable of cell division even when mature; constitutes the greater part of leaves, roots, the pulp of fruits, and the pith of stems.

Parthenocarpy: The development of a fruit without fertilization or seeds. Stimulative: induced by pollination or chemical treatment; or vegetative: occurring without external influence.

Pathogen: Any organism that causes disease.

Pedicel: The stalk of a single flower of an inflorescence or of a berry.

Peduncle: Stalk of an inflorescence or flower head. In grapes, the peduncle is the same as the cluster stem, meaning from the point of attachment to the shoot to the first lateral branch on the cluster.

Permanent wilting point: Soil moisture content at which plants can no longer get water from the soil and will wilt and die. Often abbreviated as PWP.

Perennial weed: A weed that reproduces by seed and/or by vegetative means, living two or more years.

Perennial wood: Woody growth that is retained year after year.

Perfect flower: Flower with functional male parts (stamens) and female parts (pistils).

Pericarp: The part of a fruit formed from the wall of the ripened ovary; fruit wall. The pericarp consists of the endocarp, mesocarp, and exocarp.

Periderm: Protective tissue that replaces the epidermis after the growth of phloem is initiated.

Pest: Any unwanted and/or destructive disease, insect, or weed.

Petiole: Stalk of a leaf blade.

Phenolic compounds: Phenolic compounds in grapes and wines include several hundred chemical compounds that strongly influence taste, color, and mouthfeel. Tannins and anthocyanins are phenolic compounds, as are many other chemical constituents of grapes and wines. Some of these are naturally present in the fruit and some are created as a function of the winemaking and aging process. Phenolic compounds such as Resveratrol have been linked to many of the health-beneficial properties of grapes and grape products.

Phenology: the study of the time of appearance of characteristic periodic phenomena in the life cycle of organisms in nature, e.g., migration in birds and flowering and leaf-fall in plants, particularly as these phenomena are influenced by environmental factors. Phenology especially involves the effects of temperature or day length.

Phenotype: The external appearance or a measurable characteristic of an individual.

Pheromone: A chemical substance secreted by insects to affect the behavior or development of other members of the species; specifically a sex pheromone used to attract members of the opposite sex.

Phloem: The region of living vascular tissue in plants, external to the cambium, that carries sugars and carbohydrates (which are formed during photosynthesis) from the leaves downward toward the roots.

Phytoplasma: Any of various specialized bacteria that are obligate parasites of plant phloem tissue and of some insects.

Photosynthesis: The production of sugar from carbon dioxide and water in the presence of chlorophyll, activated by light energy and releasing oxygen.

Phytotoxic: Toxic to plants.

Pistil: The female part of a flower, consisting of a stigma, a style and an ovary.

Pistillate flower: A flower with only female parts (pistils).

Pith: Soft, sponge-like tissue found in the center of stems. Made up of parenchyma cells.

Pollen: Male spores produced in the anthers of a flower.

Pollination: The transfer of pollen to the stigma of a flower.

Pomace: Grape skins, seeds, stems and pulp that remain after the grapes have been pressed. Also known as marc.

Predacious: Feeding as a predator.

Pre-emergent herbicide: Herbicide that is applied before weed seedlings emerge from the ground, that kills them upon their emergence.

Pre-plant: Treatments applied before main crop plants are planted.

Pressing: Extracting juice from grapes using a wine press.

Primary bud: In grapevines, the central, largest, and most fruitful bud in a compound winter bud, which usually develops into a fruiting shoot in the following growing season.

Primary fermentation: Initial fermentation, in which yeast convert sugars in grape juice or must to alcohol (wine) and carbon dioxide. Also see malolactic fermentation.

Primordia: An organ or tissue in its earliest recognizable stage of development.

Protectant: A chemical applied to a plant surface before infection.

Pubescent: Covered in short, fine, soft epidermal hairs.


Quarantine: A legal action preventing the sale or shipment of plants or plant parts to prevent the spread of a disease or pest.


Rachis: 1. The main stem that runs from the peduncle down through the cluster of grapes. 2. Axis of a compound leaf or compound inflorescence.

Racking: The process of siphoning wine off the lees (sediment at the bottom) into a new, clean vessel, clarifying the wine.

Re-entry interval, re-entry period: The period of time specified by law that must elapse after a pesticide is applied before people can resume work in the treated area. Often abbreviated REI.

Refractometer: An instrument, usually hand-held, that measures dissolved sugar in a small juice sample in the field; makes it possible to determine ideal harvesting times of grapes so that the product arrives in an ideal state to consumers or for subsequent processing steps such as vinification.

Residual: Length of time for effective control by a pesticide after application.

Residual sugar: Sugar not converted to alcohol during fermentation. Usually measured in grams of sugar per litre of wine (g/L). Indicative of a wine's relative sweetness.

Resistance: Developed ability of a pest to withstand a pesticide.

Renewal spur: In grapevines, the cane that is pruned to one or two nodes on the cordon; becomes the fruiting cane the following year.

Rhizosphere: Rooting zone. Soil around a plant's roots.

Rootstock: Grape variety used as the underground portion of a grafted vine onto which the scion is grafted. Bred to provide pest resistance and/or adaptability to unfavorable soil or environmental conditions.

Rosette: A spiral of overlapping leaves growing on a shortened stem and emerging from a central point, growing in circles around that center.

Row: A row consists of a strip of plants growing side by side in a line.

Rugose: Wrinkled, puckered, or uneven.


Sanitation: Removal or destruction of pest breeding, refuge, and overwintering sites as well as pest food sources or the pests themselves; cleaning of infected tools and field equipment.

Scion: A short piece of stem containing buds, taken from one plant and grafted onto the rootstock of another.

Scuppernong: A variety of muscadine (Vitis rotundifolia). Greenish or bronze American grape native to the southeastern U.S. Named for the Scuppernong River in North Carolina.

Second crop: Clusters initiated and produced in the current season and borne on lateral shoots, that bloom and mature later than the main crop.

Secondary bud: In grapevines: the second largest of the three buds in a compound winter bud, generally less fruitful than the primary bud, and does not develop unless there is damage to the primary bud (e.g., frost injury).

Secondary fermentation: In winemaking, either a continuation of the primary fermentation of sugar to alcohol that takes place after the wine is moved from one type of container to another, such as from stainless steel to oak, or a supplemental fermentation triggered after the primary fermentation is complete by the addition of sugars, such as is commonly done in the production of sparkling wines.

Selective herbicide: Herbicide that kills certain types of plants without affecting other types of plants. For example, broadleaf herbicides kill broadleaf weeds but not grasses.

Self-pollination: Fertilization by transfer of pollen from the anther to the stigma of the same flower, or to different flowers on the same plant.

Senescence: The active, highly ordered and genetically regulated process through which a biological organism, or one of its parts, progresses after maturity; leaf fall is preceded by senescence, involving loss of chlorophyll and other chemical and physical changes.

Sepal: Leaf-like parts on the outside of a flower. Usually green and just under the petals. Collectively called the calyx.

Serrations: Tooth-like indentations at the margin of a leaf.

Shatter: A condition in which individual grape berries become separated from the stem. May be caused pre-harvest by cool, wet weather during early grape development, which tends to prevent the flower caps from falling off. Then, after the berries start to grow, they push against the cap and shatter, significantly reducing yields. May be caused post-harvest by rough handling during harvest and shipping.

Shoot: New green growth with leaves, tendrils, and often flower clusters, developing from a bud of a cane or spur.

Shoot thinning: The act of removing shoots in order to facilitate improved fruit size and fruit quality in retained fruit, as well as to reduce vine stress.

Shot berry: Shot berries are small, undeveloped grapes, usually seedless. Millerandage is the French term for this condition, in which some grapes in a bunch do not develop fully, resulting in different sized berries having different maturity levels. The condition is also known as “hen and chicks”. Shot berries are often caused by cold, wet weather during flowering. They produce lower quality wine.

Shouldered cluster: A grape cluster that has a portion with a branched rachis.

Sink: The point or place where a substance is absorbed or removed from a system. For example, during ripening, a leaf is the source of photosynthate while fruits are a sink.

Sinus: Cleft or indentation between the lobes of a leaf blade.

Slip-skin: Characteristic of grape varieties where the skin of a mature grape separates easily from the pulp.

Sod culture: Orchard or vineyard plants growing in turf or grass that is periodically mowed.

Soil fumigant: A chemical injected or incorporated into the soil to control soil-borne diseases of pests.

Soil structure: The way in which individual soil granules clump or bind together to form larger pieces called aggregates. Soil structure includes the soil pores between aggregates, and it influences movement of water, air, microbes, and roots.

Soil texture: The relative proportion of sand, silt and clay particles in a soil.

Source: The point or place from which something originates. For example, during ripening, a leaf is the source of photosynthate while fruits are sinks.

Species: A group of similarly classified organisms but different from other groups within the same genus.

Spur: A cane pruned back to one, two, or three buds.

Stamen: The male reproductive organ of a flower.

Staminate flower: A male flower, bearing only stamens.

Stemmer-crusher: A machine that removes grape berries from the stems and then breaks the skins of the berries. Also known as a destemmer-crusher.

Stenospermocarpy: The biological mechanism that produces seedlessness in some fruits, even though those fruits have undergone normal pollination and fertilization. The resulting embryo is aborted, but the fruit continues to grow. The remains of the undeveloped seed can be seen in the fruit. Also see parthenocarpy.

Stigma: The top of the style, where pollen enters the pistil.

Stock: Grape variety used as the underground portion of a grafted vine onto which the scion is grafted. Bred to provide pest resistance and/or adaptability to unfavorable soil or environmental conditions. Also known as a rootstock.

Stomate: A tiny pore in a leaf that allows gas exchange (of water vapor, oxygen, and carbon dioxide). Stomates are usually found on the underside of the leaf. Plural stomata or stomates.

Strategic leaf pruning: The act of removing specific leaves to expose fruit to sunlight and to improve air flow through the canopy.

Stratification: Process of pretreating seeds to remove their physiological dormancy and get them to germinate. Stratification requires cold (usually around 40ºF), moist (but not wet) conditions for a period of time (usually 3-8 weeks).

Style: The part of the pistil between the ovary and the stigma.

Suberin: Waxy, waterproof substance found in plants. Wine corks are made of suberin and are taken from the bark of the cork oak (Quercus suber).

Succulent: 1. Thick and fleshy, usually said of leaves. 2. A plant having fleshy tissues that conserve moisture.

Sucker: A shoot growing from old wood. Usually, a sucker refers to a shoot growing at the trunk base.

Suckering: The process of removing suckers or other unwanted shoots.

Sulfites: Sulfur-based compounds that occur naturally during wine fermentation, but are also often added before, during, or after fermentation. They protect wine from oxidation and the activity of undesirable microorganisms, particularly bacteria. Sulfites are typically added at higher levels to white and/or sweet wines to prevent browning and/or spoilage.

Sunscald: Plant damage usually caused by exposure to bright sunlight, although it may also be caused by excessive heat and/or wind. Sunscald is often seen when plant parts are suddenly exposed to sunlight, as with a sudden loss of leaves (often caused by insect feeding), or when nearby trees or other plants are cut down.

Supercooling: The cooling of hydrated tissue or a liquid below its freezing point without a phase change to solid; the mechanism by which grape buds survive winter minimum temperatures.

Surfactant: (from surface active agent) Material used in herbicide formulations to bring about emulsifiability, spreading, wetting, sticking, dispersibility, solubiiization or other surface-modifying properties. Also see adjuvant. From: Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.

Susceptible: Likely to be affected by, or highly sensitive to, a disease, insect, or environmental condition.

Systemic: Something (e.g., chemical, disease, plant growth regulator) that spreads internally throughout a plant.

Systemic herbicide: Herbicide that is translocated through the plant, either from foliar application down to the roots, or from soil application up to the leaves. Also see contact herbicide.


Tannin: Tannins are in a class of compounds known as phenolics and are found in grape skins and seeds. These are important in red grapes for wine production and quality. In red wine, tannins cause a dry or astringent mouthfeel. While fruit and seeds can provide tannins to finished wines, tannins are also extracted from oak barrels or oak chips during fermentation and aging.

Teinturier: French term meaning dye or stain. Refers to grapes whose flesh and juice is red due to anthocyanin pigments accumulating within the pulp of the grape berry itself, rather than just the skin. Few grape cultivars have red pulp.

Temperature inversion: The condition on a clear night during which air temperature is coldest near the ground and increases with altitude.

Tendril: Twisting, clinging, slender stem-like structure on vines. Tendrils attach themselves to a trellis or post to provide support for the plant. In grapes, tendrils are found opposite a cluster and leaves.

Tensiometer: Instrument for measuring the moisture content of soil. The instrument consists of a column to be filled with water with a ceramic tip and a vacuum gauge to measure tension. A tensiometer works by measuring the amount of tension that the soil exerts on the instrument as it loses soil moisture and water is removed from the instrument.

Terpenes: A class of organic compounds important as odorants of the highly aromatic muscat grapes and related varieties such Riesling and Gewurtztraminer.

Terroir: (French) The combination of factors, including soil, climate, and environment, that gives a wine its distinctive character.

Tertiary bud: The smallest of the three buds. It is generally more cold hardy than either primary or secondary buds but the least fruitful, and it usually does not develop unless the primary and secondary buds have been killed.

Tetraploid: Plant with four sets of chromosomes, which is twice the normal amount.

Threshold: The point at which an action is taken; often applied to insects. (Most thresholds are action thresholds; an action is taken when a pre-determined number of a given insect is present in the soil or on a cotton plant. It can also be an economic threshold, which takes the commodity value and treatment cost into consideration when determining when to apply control measures.)

Tissue analysis: Analysis of a tissue sample for mineral nutrient/element composition.

Tissue culture: The growth of small pieces of animal or plant tissue in a sterile controlled medium.

Titratable acidity: Acidity of a juice, must or wine determined from the amount of base needed to titrate the wine to a specific end point pH. Usually sodium hydroxide (NaOH) is used for titration to an end point pH of 8.2 in the US and 7.0 in France. Titratable acidity is reported in g/L tartaric acid equivalents and often abbreviated as TA.

Tomentum: A hairy covering of short, closely matted hairs.

Topping up: Replacing wine that has evaporated from a barrel, ensuring no air space in the container and no exposure to oxygen.

Topworking: Changing a cultivar by grafting a new one onto the trunk.

Trace elements: Minerals needed in very small amounts. In plants, these would include micronutrients such as the elements iron, boron, and zinc.

Tuberosity: Damage to larger roots by the feeding of phylloxera, creating significant damage to grapevine roots.

Training, grapevine: The arrangement of plant parts spatially, done to develop a structure that optimizes the utilization of sunlight and promotes productivity, adapts to the characteristics of the grape cultivar, promotes efficient and sustainable vineyard management practices, and is economical to establish and maintain. Vines are often trained to a given trellis (posts, wires) and once complete is a “training system.”

Translocation: Movement of solutes and water within a plant from the roots to plant parts or from one plant part to another through the xylem and phloem.

Transpiration: Release of water vapor from plant parts, especially the leaves via stomates.

Trellis: 1. (noun) The physical support structure used for training vines. The structure is usually made of wood or metal for vigorous vines. 2. (verb) To train on a trellis.

Trunk: The permanent, aboveground woody stem of a tree or vine.

Turgidity: Pressure inside a cell due to the uptake of water.

Tytape: Braided, non-elastic tape often used to secure grapevine to wire.


Vacuole: A large, membrane-bound, fluid-filled compartment in the cytoplasm of a plant cell.

Varietal character: Distinctive aroma or flavor characteristics of certain grape cultivars that make them recognizable.

Variety: Members of a species that differ from others of the same species in minor but heritable characteristics. Occurs naturally and may be perpetuated by humans as a cultivar. Examples include red forms of usually white flowers, or a grain with larger seeds.

Vascular elements: In plants, vascular elements consist of two complex tissues, the xylem and the phloem, through which all materials (water and nutrients) flow. Comparable to circulatory systems in animals.

Vector: An organism that transmits a pathogen from one organism or source to another. Example: An insect may act as a vector by transmitting a disease from one pig or chicken to another.

Vegetative propagation: The creation of new plants by using a vegetative part of the plant such as a leaf, stem, or root – any part other than a seed. Examples include layering, cuttings, tissue culture, and division. Same as asexual propagation.

Vein: A vascular bundle in a leaf; in grape there are usually five main veins and a number of minor veins.

Veraison: The onset of ripening. The change of color of the grape berries. Veraison represents the transition from berry growth to berry ripening, and many changes in berry development occur at version.

Vertical shoot positioning (VSP): A training system in which growth is trained upward from low cordons, most often associated with Vitis vinifera wine grapes. Commonly referred to as VSP.

Vigor: Relates to the relative robustness of a plant in comparison to other individuals of the same species. It is reflected primarily by the size of a plant and its parts in relation to its age and the environment in which it is growing. Syn. plant vigor. cf. hybrid vigor. From: Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.

Vine density: The number of vines planted per unit area.

Vine shelter: Plastic or waxed cardboard tube that fits around a young plant and helps protect it from predators and directed herbicide applcations. Often used for trees and grape vines in the year of planting. Also known as a grow tube.

Vine size: Total current season’s growth of a vine and an indicator of a vine’s capacity.

vinifera: European grape native to the Mediterranean and Central Asia. Also known as Old World grapes. Called 'vinifera' after its scientific name Vitis vinifera.

Vinify: To turn grape juice into wine.

Vintage: 1. A season's yield of wine from a vineyard. 2. The year in which grapes were harvested to create a wine.

Virus: Simple submicroscopic parasites of plants, animals, and bacteria that consist a core of RNA or DNA surrounded by a protein coat; they can replicate only inside the living cells of organisms. Often cause disease. Also, the disease caused by infection by a virus.

Virus-tested: Subjected to screening for viruses by plant indexing or laboratory procedures.

Viticulture: 1. The cultivation of grapes. 2. The science of growing grapes.

Vitis labrusca: American grape, sometimes known as fox grape. Primary uses are for juice, jams and jellies although these grapes can be used for sweet wines or eaten fresh. Most commonly known cultivar is 'Concord'. Native to the Eastern United States and Canada.

Vitis rotundifolia: Also known as muscadines. American grape native to the Southeastern United States from Delaware to the Gulf of Mexico. Also see scuppernong.

Vitis vinifera: European grape native to the Mediterranean and Central Asia. Also known as Old World or European grapes. Also see American grape.


Waterberry: A disorder of ripening grapes in which sugar accumulation stops and grapes become soft and watery.

Water sprout: A shoot growing from adventitious buds in old wood, rather than from shoots or canes. Also see sucker.

Weed: 1. Any plant growing where unwanted. 2. A plant having a negative value within a given management system. From: Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.

Wettable powder: Dry formulation that must be mixed with water or other liquid before it is applied.

Wing: The well developed basal lateral branch of a rachis separated from the main body of the cluster.

Wilt: Loss of freshness or turgor of plants because of inadequate water supply or excessive transpiration; also a vascular disease interfering with water transport.

Winkler Region: A means of classifying climate of grape growing regions based on heat summations; originally developed for California but used in other regions.

Wire moving: In viticulture: The act of positioning of foliage wires so that growing shoots are oriented in the correct direction appropriate for a trellis system.


Xylem: Vascular tissue in plants primarily responsible for the distribution of water and minerals taken up by the roots. Makes up most of the sapwood of a tree or vine.


Yeast: Single-celled microorganism used to convert sugar to alcohol and carbon dioxide during the fermentation stage of wine production.

Yield-to-pruning weight ratio: A measure of the balance between vegetative growth (current season) and fruit production.

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