Grapevine is an interesting plant not only that it produce some of the best fruit on earth which can be transformed into the wine, but also as the plant itself. Grapevine is a permanent plant but differs from other permanent plants in many ways. So, in order to successfully maintain vine and produce the best possible grapes and thus the wine, it’s important to know each and every grapevine parts and it’s functions. For this reason, we have decided to make a series of posts on grapevine structure.

In the first part, we will shortly introduce all the basic parts of grapevine.

Grapevine is a climber which naturally grows on the trees and bushes, high and in wide shapes. In the vineyard its growth is maintained with the pruning in order to control the quantity and quality of the grapes.

Like any other plant also grapevine has its underground and above-ground part. The underground part consists of an underground trunk with the root system. While the above ground part consists of the trunk, canes, and shoots. On the one-year-old shoots, there are leaves, tendrils, flowers, and grapes.

Photo (Dave Johnson for Bay Area News Group): Grapevine Structure – Overview

Root system – the roots of a grapevine are multi-branched structures that grow to various depths into the soil depending on the variety (rootstock), soil and climate. Some varieties develop very deep and almost vertical roots while others have very flat and shallow roots system and therefore requires deep, fertile soil.

Trunk – is the main steam, it’s permanent and supports the above-ground vegetative (leaves and stems) and reproductive (flowers and fruits) structure of the vine. The height of the trunk and also its branched varies with the selected training system. In cane-pruned training system, the top of the trunk is called the head. Fully developed trunk has arms – short branches from wich canes and spurs originate. Depending on a selected training system arms are located in different positions. In training system that utilize canes (cane-pruned training system) – one-year-old wood arise from arms usually near the head of the vines. While in training system that utilizes cordons (cordon training with spur pruning) arms are spaced at regular intervals along their length. *Cordons are extensions of the trunk that usually grows horizontally along a trellis wire.

Canes – When the shoots mature and woody, it becomes a vine cane. Canes if therefore one year old, woody and, matured shoot; after the leaves has fallen off. Canes are the main concerns for winegrowers during the dormant season. With the winter pruning of canes, winegrowers are managing vine size and shape and therefore control the quality of crop in the coming season.

Buds – develop in the leaf axil, right above the connection between the shoot and leave petiole. Inside each bud, there are three distinct growing points, each capable of producing a shoot, also known as primary, secondary and tertiary buds. Bud is actually a highly compressed shoot with all its parts, including cluster. At bud burst normally primary bud begins to grow, but sometimes also secondary or tertiary buds, so there can be two or three shoots on the same axil. In case the primary bud is damaged or freezes, then the secondary or tertiary buds grow in place of the primary bud. In comparison to the primary bud secondary and tertiary buds generally, have little to no fruit.

Shoots – are green stems which develop from buds, and represent the primary growth structure of grapevines. The shoots that arise from primary (winter) buds are normally the fruit-producing shoots. The shoot consists of stems, leaves, tendrils and fruits. *Canopy is a collective term that is used to describe the shoots, leaves, and fruits of the grapevine.

Leaves – The leaves of the grapevine, as any other plant, provide nourishment and air for the plant. Leaves are converting sunlight into usable energy for the plant. More leaves are well sunlit more organic compounds the grapevine can use for its growth. The shape and size of leaves are determined by the grapevine variety, as well as color, which varies from light to dark green.

Tendrils – are a slender structure that appears on the top and sides of stems. They grow until the grapevine is ready for harvest, after the harvest they become wooden in nature. Since the grapevine is a climber it needs tendrils to coil around small objects such as fences, trellises, etc. to reach up for the sun and heat. Tendril and flower cluster have a common development origin, therefore, we might find flowers design developed at the end of the tendril.

Flowers and Grapes – Flower cluster grow on the opposite site then leaves along the shoot. Most fruitful shoots develop from one to three flower clusters depending on the variety and growing conditions. Each cluster may contain only a few or up to several hundred flowers at the time of bloom; the number depends on the variety and environmental conditions. When fertilized, the flower clusters develop into clusters of grapes – the fruit set – and the berries start to grow.

Sources:
Grapevine Structure and Function, by Edward W. Hellman
Grapevine Structure and Function, in Grape Grower’s Handbook, by Ted Goldammer
Lexicon of grapevine
Photo source: Dave Johnson for Bay Area News Group

Grape vine

Facts

  • Vine cultivation and wine production kicked off in Armenia. It then spread to Eqypt and Phoenicia and around 4,000 years ago to Greece. The Greeks took the art of viticulture around the Mediterranean and the Romans spread the knowledge up the river valleys into France and Germany.

Where it grows

  • Wild grapes thrived in the warm, damp, wooded lowland valleys from Turkestan, deep in Asia, through Armenia into Thrace.
  • Water is a precious resource and vineyards use a lot of it, but experiments are being conducted in Australia where roots on one side of the vine are kept in dry soil while roots on the other side are irrigated. The process is then reversed. This results in less side shoots and more grapes, which requires less pruning and offers savings in money and water.

Common uses

Grapes are eaten fresh and dried. Sultanas are soft, juicy amber-coloured fruits with a sweet flavour produced from seedless white grapes, mainly Thompson Seedless. Raisins are dark brown and wrinkled with a sweet mellow flavour. Currants are dried, black seedless grapes from a variety called Corinth, grown in Greece for more than 2,000 years.

Grape juice is widely drunk and, of course, used to make wine. The strong glass bottles with corks developed in the 17th century were the key to the type of wines we produce today. Although grapes are mostly crushed mechanically these days, they are still crushed by foot in some areas. Years ago the sugars in the grape juice were turned to alcohol by the yeast on the skins; today things are carefully controlled. Wine is more often sterilised and the yeast added. Good wine vintages are stored for around three years in heavy wooden casks. The tannin from the oak casks helps to preserve the wine when it is bottled. One of the reasons that good wines cost so much is that these casks have to be renewed every five years.

Apart from using various grapes, different types of wine are made by adjustments in the fermentation process. Champagne is made by bottling before fermentation has finished allowing the process to finish in the bottle. Sweet wines have their fermentation brought to a premature halt by the addition of sulphur. Port is made by arresting fermentation by the addition of alcohol. Brandy, which contains the most alcohol, is made by distilling wine.

Useful links

  • Plants for a Future
  • Royal Horticultural Society
  • University of Maryland Medical Centre
  • American Cancer Society

Glossary

  • Lobe: incomplete division in any plant organ (eg leaf).
  • Palmate: when all lobes originate from a central point.
  • Panicle: multi-branched collection of flowers (inflorescence).
  • Tendrils: slender coiling structure.

Trunk Shoots Tendrils & Buds Suckers & Watersprouts Canes More Info

Ed Hellman, Texas AgriLife Extension

The Trunk

The trunk is permanent and supports the arms of the grape vine. Illustration courtesy of Eric Stafne, Mississippi State University.

The trunk, which was formerly an individual shoot trained as the trunk in a young vine, becomes permanent and supports the above-ground vegetative (leaves and stems) and reproductive (flowers and fruits) structures of the vine. The height of the trunk varies with the training system selected. For cane-pruned training systems, the top of the trunk is referred to as the head. The height of the head is determined by pruning during the initial stages of training a young grapevine (or replacement trunk). The trunk of a mature vine will have arms, short branches from which canes and/or spurs originate, which are located in different positions depending on the system. Some training systems utilize cordons, semi-permanent branches of the trunk. Cordons are usually trained horizontally along a trellis wire, with spurs spaced at regular intervals along their length. Where bilateral training systems are used, the cordon is trained to either side of the trunk, and some growers refer to each of the two sides of the cordons as arms. Other systems utilize canes, one-year-old wood arising from arms and usually located near the head of the vine. Multiple trunks are often used in grape growing regions that are at risk for winter injury. The term “crown” refers to the basal region of the trunk slightly below and above the soil level.

Shoots and Canes

The shoot consists of stems, leaves, tendrils, and fruit and is the primary unit of vine growth and the principal focus of many vineyard management practices. Shoots arise from compound buds that are initiated around bloom during the previous growing season. Each compound bud can potentially produce more than one shoot. Primary shoots arise from primary buds (described below) and are normally the fruit-producing shoots on the vine. The main axis of the shoot consists of structural support tissues and conducting tissues to transport water, nutrients, and the products of photosynthesis. Arranged along the shoot in regular patterns are leaves, tendrils, flower or fruit clusters, and buds. General areas of the shoot are described as basal (closest to its point of origin), mid-shoot, and apex (tip). The term canopy is used to describe the collective arrangement of the vine’s shoots, leaves and fruit; some viticulturists also include the trunk, cordons and canes.

Shoot tip. The shoot has many points of growth that will be described in more detail below, but the main shoot growth in length occurs from the apical meristem, located at the shoot tip. New leaves and tendrils unfold from the tip as the shoot grows. Growth rate of the shoot varies during the season. Grapevine shoots do not stop expanding by forming a terminal bud as some plants do, but may continue to grow if there is sufficient heat, soil moisture, and nutrients.

Leaves. Leaves are produced at the apical meristem. The shoot produces two or more closely spaced bracts (small scale-like leaves) at its base before it produces the first true foliage leaf (Pratt, 1974). Leaves are attached at the slightly enlarged area on the shoot that is referred to as a node. The area between nodes is called the internode. The distance between nodes is an indicator of the rate of shoot growth, so internode length varies along the cane corresponding to varying growth rates during the season.

Leaves consist of the blade, the broad, flat part of the leaf designed to absorb sunlight and CO2 in the food manufacturing process of photosynthesis, and the petiole, the stem-like structure that connects the leaf to the shoot. The lower surface of leaf blade contains thousands of microscopic pores called stomata (singular = stomate), through which diffusion of CO2, O2, and water vapor occurs. Stomata are open in the light and closed in the dark. The petiole conducts water and food material to and from the leaf blade, and maintains the orientation of the leaf blade to perform its functions in photosynthesis.

Tendrils. The shoot also produces tendrils, slender structures that coil around smaller objects (i.e., trellis wires, small stakes, and other shoots) to provide support for growing shoots. Tendrils grow opposite a leaf at the node, except the first two or three leaves at the base of the shoot. Thereafter, tendrils can be found opposite leaves, skipping every third leaf. Flower clusters and tendrils have a common developmental origin (Mullins et al., 1992), so occasionally a few flowers will develop on the end of a tendril.

Buds. A bud is a growing point that develops in the leaf axil, the area just above the point of connection between the petiole and shoot. The single bud that develops in this area is described in botanical terms as an axillary bud. On grapevines, a bud develops in every leaf axil, including the inconspicuous basal bracts (scale-like leaves). In viticulture terminology, the two buds associated with a leaf are termed the lateral bud and the dormant bud (or latent bud). The lateral bud is the true axillary bud of the foliage leaf, and the dormant bud forms in the bract axil of the lateral bud. Because of their developmental association, the two buds are situated side-by-side in the main leaf axil. Each bud is a compound bud, containing three distinct growing points, each capable of producing a shoot. These are commonly referred to as the primary, secondary, and tertiary buds, respectively. At bud burst, the primary bud is typically the only bud that begins to grow. If the primary bud is damaged, then the secondary and/or tertiary buds are released from dormancy and grow in place of the primary bud. These secondary and tertiary buds generally have little to no fruit in comparison to the primary bud.

A cross section of a dormant bud. The three buds within the compound bud can be seen. Photo by Patty Skinkis, Oregon State University.

Suckers and Watersprouts. Latent buds embedded in older trunk and cordon wood may also produce shoots. Suckers are shoots that grow from the crown area of the trunk. Watersprout is sometimes used to refer to a shoot arising from the upper regions of the trunk or from cordons (Winkler et al., 1974). Buds growing from older wood are not newly initiated buds, but rather they developed on green shoots as axillary buds that never grew out. These latent buds can remain dormant indefinitely until an extreme event such as injury to the vine or very severe pruning stimulates renewed development and shoot growth (Winkler et al., 1974).

Suckers often arise from latent buds at underground node positions on the trunk. In routine vine management, suckers are removed early in the season before axillary buds can mature in basal bracts of the sucker shoots. Similarly, above-ground suckers are typically stripped off the trunk manually so a pruning stub does not remain to harbor additional latent buds that could produce more suckers in the following year.

Latent buds come into use when trunk, cordon, or spur renewal is necessary. Generally, numerous latent buds exist at the “renewal positions” (a pruning term) on the trunk or cordons. Dormant secondary and tertiary buds exist in the stubs that remain after canes or spurs have been removed by pruning.

Canes. The shoot enters a transitional phase, starting around veraison, when it begins to mature or ripen. Shoot maturation begins at the shoot base as periderm develops, starting at the shoot base, appearing initially as a yellow, smooth “skin”, and continues to form outward toward the shoot tip through the remainder of summer and fall. As periderm develops, it changes from yellow to brown, and becomes a dry, hard, smooth layer of bark. During shoot maturation, the cell walls of ray tissues thicken and there is an accumulation of starch (storage carbohydrates) in all living cells of the wood and bark (Mullins et al., 1992). Once the leaves fall from the vine at the beginning of the dormant season, the mature shoot is considered a cane.

The cane is the principal structure of concern in the dormant season, when pruning is employed to manage vine size and shape, and to control the quantity of potential crop in the coming season. Because a cane is simply a mature shoot, the same terms are used to describe its parts. Pruning severity is often described in terms of the number of buds retained per vine or bud count. This refers to the dormant buds, which in a single bud contains three growing points as described above. When considering a dormant cane, the buds located at the very base of a cane include secondary and tertiary growing points that give rise to the axillary buds of the shoot’s basal bracts (Pratt, 1974). It should be noted that the most basal buds on a cane are generally not fruitful and do not grow out, so they are not included in bud counts. These are often referred to as non-count buds during the pruning process.

Canes can be pruned to varying lengths, and when they consist of only one to four buds, they are referred to as spurs, or often, fruiting spurs. Grapevine spurs should not be confused with true spurs produced by apple, cherry, and other fruit trees, which are the natural fruit-bearing structures of these trees. On grapevines, spurs are created by short-pruning of canes. Training systems that use cane-pruning also use spurs for the purpose of growing shoots to be trained for fruiting canes in the following season. These spurs are known as renewal spurs, indicating their role in replacing the arms.

Mullins, M. G., A. Bouquet, and L. E. Williams. 1992. Biology of the Grapevine. Cambridge University Press.

Pratt, C. 1974. Vegetative anatomy in cultivated grapes. A review. American Journal of Enology and Viticulture 25:131-150.

Recommended Resources

Grapevine Structure and Function, Texas A&M University

Grapevine Anatomy and Dormant Pruning, Adobe Breeze presentation, Virginia Tech

Cane Pruning Grapevines video and Spur Pruning Grapevines video, Oregon State University

Wine Grapevine Structure, pp 4-5 in ”’Winegrape Varieties in California”, University of California

Anatomy of Winter Injury and Recovery, Cornell University

Parts of the Grape Vine: Roots

Parts of the Grape Vine: Flowers and Fruit

Reviewed by Tim Martinson, Cornell University, and Patty Skinkis, Oregon State University

Grapevine’s Best Of 2016: Best Place To Shop Organic

Words by

Reykjavík is a relatively small city, but even so, sometimes you need a bit of local advice to find what you’re looking for, whether it’s a good people-watching spot, somewhere to see some contemporary art, or the best place to catch an Icelandic movie. Don’t worry, friends—we’ve got you covered via our Best of Reykjavík 2016 series. Here are some of our favourite spots in Reykjavík, for all kinds of super-fun days and nights out. Enjoy! And if you try our list, you can let us know what you thought of the selections via [email protected]

Best Place To Shop Organic

Winner: Frú Lauga
Laugalækur 6
Frú Lauga is one of the only places in Reykjavík where you can shop local and organic. It is located in Laugardalur, a little bit outside of downtown, with a greenhouse for growing fresh produce right on the spot. You can find a wide variety of enticing and delicious organic products, such as tomatoes, salad greens, garlic, milk, cream, meat, and olives. It doesn’t get more greenhouse-to-table than this—who can argue with that kind of quality?

Runner up: Heilsuhúsið
Lágmúli 9 and more
Heilsuhúsið sells a variety of health products, cosmetics, toiletries, natural foods and vitamins. The store’s goal is to nurture the body and soul by helping you maintain a healthy, eco-friendly lifestyle. The store has grown and is now located in five different locations, all of which have a juice bar. We recommend trying a shot of ginger or wheatgrass while you shop.

Previous Winner:
2015: Frú Lauga
2014: Frú Lauga
2013: Frú Lauga
2012: Frú Lauga
2011: Frú Lauga

Read more of our Best of 2016 lists here.

Support The Reykjavík Grapevine!
Book your day tours in Iceland right here!

Blister Mite Control On Grapes: Treating Grape Leaf Blister Mites

If you’ve noticed irregular blotches or blister-like lesions on your grape leaves, you may be wondering what, or who the culprit is. Although you may not see them, chances are good that this damage is the product of blister leaf mites. Read on to learn how to spot grape erineum mite damage and what other grape leaf blister mite info is helpful for controlling or eradicating these pests.

Grape Leaf Blister Mite Info

Adult blister leaf mites are tiny — smaller than a mote of dust. But if you could view them with the naked eye, you would see cream-colored worms with two pairs of legs. Grape erineum mite damage appears on young leaves as dark green to pink tinged swellings on upper areas. The underside of leaves have a concave appearance, littered with blister-like edemas covered with a felted carpeting of dense long leaf hairs.

Erineum mites overwinter on

the grapevines and move on to the new growth in the spring. They feed in groups beneath the swellings and, as their numbers increase, move to new areas of the vine. From late summer into autumn, the mites move back to the bud scales to overwinter.

While unsightly, treating grape leaf blister mites is generally unnecessary. Leaves afflicted with the erineum galls or swellings function normally and there is no effect on grape production unless the vine is suffering from additional grapevine diseases, pests or environmental stresses. These mites can affect growth and production of newly planted, very immature vines, however, so blister mite control in these cases may become needed.

Blister Mite Control

Different grape varieties are more susceptible to erineum mites. In young plants, removing and disposing of infested leaves can control light infestations.

A natural predator, Glaendromus occidentalis, feeds on erineum mites. Introduction of this predator has some effect on reducing their numbers; however, the tiny mites are often protected by the dense hairs of the galls.

In vineyards, blister leaf mites are rarely an issue when the property has been routinely treated for powdery mildew with application of sulphur early in the growth season. A number of other chemical sprays used for the control of leafhoppers and spider mites also stem the population of blister leaf mites.

For the home grower, however, again, there is very little need for treating grape leaf blister mites with a chemical measure. The affects done by these tiny mites is primarily aesthetic and should simply be tolerated. You should still get a bumper crop of grapes provided all other conditions are favorable.

Table grape growing, non commercial

Diseases

Powdery mildew

Powdery mildew is probably the most common disease of grapevines in the home garden. The disease becomes conspicuous as a grey/white powdery growth on all green parts, including leaves, shoots and berries.

Powdery mildew on grape vine leaves.

The berries may split and the pulp will often dry out. A fortnightly application of wettable sulfur or sulfur dust should be applied from mid September to late December. It is best to apply wettable sulfur early in the growing season and sulfur dust once the fruit has set. Do not apply sulfur on days when the maximum temperature is predicted to be 30°C or higher. Sprays containing bicarbonate of soda can also be used from early in the growing season to contain mildew.

Powdery mildew on grapes.

Downy mildew

This was was first detected in WA vineyards in 1998 but may not be a problem for the home gardener. The disease first appears on the upper surface of leaves as small yellow oilspots. The spots may enlarge to cover the leaf. A downy growth appears on the undersides of the oil spots.

As a preventive measure applications of copper oxychloride can be applied.

Pests

Bunch mites

Bunch mites are not visible to the naked eye. Adults are less than 0.2mm long and are found on the leaf underside close to the bunches. The mites damage the berry stalks by interrupting the water supply which causes the berries to shrivel and fall off. Do not confuse this with wind-suck which may happen in hot, dry windy weather as the roots withdraw water back from the berries as a method of survival.

Grape leaf blister mite

Blisters on a grape leaf

These mites cause blistering of the leaf on the upper-surface. On the under-surface felt-like patches develop. Although the leaves become unsightly, fruit production is not affected. A spray of lime sulfur applied at bud-swell should give adequate control.

Nematodes

The sandy soils on the coastal plain near Perth are known to contain root-knot nematodes (Meloidogyne sp.) which can destroy the root system of the vine as the vines get older. Table grapes grown on a nematode-resistant rootstock will perform much better than vines growing on their own roots but are harder to obtain through garden centres.

Natter’s Notes

Blister Mites: Grapes; Pears; Walnuts

Jean R. Natter, OSU Master Gardener

Erineum mite damage on home garden grape leaves: “Blisters” on the top; corresponding concave areas on reverse filled white fuzzy material (enlarged leaf hairs). (J.R. Natter; 2016-04)

Blister mites are running wild this season. It seems that the perfect conditions combined for population explosions of these tiny, elongated mites which noticeably disfigure the leaves of grapes, pears, walnuts, and more. Among pears, even newly planted trees are victims. The symptoms are similar on all three genera but the specific causal agents – also referred to as eriophyid mites or simply eriophyids – vary.

Blister or eriophyid mites reside on the undersides of the leaves, injecting fluids into the leaf tissue as they feed. Those fluids cause the blistering on the top surface with the associated white “fuzz” (enlarged plant hairs) in the concave areas on the reverse. (So, no, it’s not fungal growth.)

Blister mites are far different than the more common spider mites. Adults are microscopic, light in color, cylindrical, tapered at the posterior end, with two pairs of short legs just behind the head. Nymphs are the same but are smaller.

Microscopic image of an erineum mite, Aceria species, elongated, 2 pair legs, size about approximately 1/100-inch. (https://utahpests.usu.edu/uppdl/files-ou/factsheet/eriophyid-mites2010.pdf)

Grape Erineum Mites (Colomerus vitis) are microscopic, wormlike, with 2 short pairs of legs at the head end, and white-yellow in color. They overwinter between the outer bud scales and bud tissue and feed on leaves during spring and summer. Feeding from the undersides of the leaves produces a blistered appearance on the top of the leaves. At the same time, the corresponding depressions on the underside are filled with enlarged light-colored leaf hairs which shelter the mites from natural enemies and pesticides. In spite of how extensive and nasty-looking the infestation is, blister mites seldom affect grape health or production.

As the season progresses, the enlarged leaf hairs progress from white to yellow and, finally, brown. Then, from mid-August until leaf drop, the mites return to their overwintering sites beneath the bud scales.

Home management for grape erineum mites: Sprays aren’t needed. “Dormant-season oils and insecticides used for other pests and sulfur applications for powdery mildew usually control this pest.”

Pear Leaf Blister Mites (Eriophyes pyri) feeding causes reddish to yellowish green blisters on the top surface of the leaves, often in 2 lengthwise rows, one at each side of the main vein. With time, the blisters turn brown or black. Leaves may drop prematurely. Loss of excess foliage weakens trees, reduces shoot growth, and interferes with fruit maturation and fruit bud formation. Feeding on fruit causes irregular, russeted spots which feel rough and somewhat scaly. PNW Insect says “Eriophyid mites move from tree to tree, perhaps by wind or carried on birds or insects.”

Home Management for Pear Leaf Blister Mites: Lime sulfur applications in the fall can significantly reduce populations of these mites the following year. (The trick, though is to obtain it in small home-use packaging.) Applications before bud swell can also be effective. Or apply superior oil as buds begin to swell.

Walnut Blister Mites (Aceria erineus)

Just as do the previous two mites, walnut blister mites overwinter beneath bud scales. When springtime temperatures rise, the mites feed among the leaf hairs on the undersides of the leaves. Several generations occur during the summer, which attack new foliage as soon as it unfurls.

Home Management of Walnut Blister Mites: Naturally-occurring predator mites almost always keep mites under control if broad-spectrum insecticide applications are avoided. Heavy rain and cold weather also suppress mite numbers.

Broadleaf weeds like mallow, bindweed, white clover, and knotweed enhance mite numbers. Avoid excessive nitrogen applications, as this encourages mites.

Horticultural oil is the only spray suggested for home-use.

Resources

Eriophyid Mites:

Grape Erineum Mites: https://pnwhandbooks.org/insect/small-fruit/grape/grape-grape-erineum-mite

Pear Leaf Blister Mites: https://pnwhandbooks.org/insect/tree-fruit/pear/pear-eriophyid-mite

Walnut Blister Mites: https://pnwhandbooks.org/insect/nut/walnut/walnut-walnut-blister-mite

(Click the link below for PDF containing the above text and all the images.)

Blister Mites – PDF

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