Grape

Description

The Common or European grapevine (Vitis vinifera) is a long stemmed, woody vine (liana) which produces high value berries, or grapes. The vines can reach lengths in excess of 30 m and can live for many years with proper management. The leaves of the grape vine are alternately arranged on the stem and are long and broad with 5–7 lobes, typically reaching sizes of 5–20 cm (2.0–7.9 in). Flowers are produced in clusters and fruit. The fruit is a berry known as a grape and grows in clusters from the vine. In wild species, the fruit is 6 mm (1/5 in) in diameter and ripens to dark purple to black with a pale wax bloom. In cultivated plants, the berry is usually much larger, up to 3 cm (1.2 in) long and can be green, red or purple. Vitis vinifera is native to the Mediterranean region, central Europe, and southwestern Asia but is cultivated on every continent except Antarctica. Most grape cultivation centers on the use of Vitis vinifera, however, in North America the related species Vitis labrusca, Vitis riparia and Vitis rotundifolia are also grown. Vitis amurensis is native to Asia and has been hybridized with Vitis vinifera to produce cold tolerant grapevine varieties.


Uses

Grapes are the most widely produced commercial fruit crop in the world. They are often eaten fresh but are also commonly used to produce wine. Grapes can also be processed into jams, and preserves, juices, grape seed oil, grape seed extract, raisins and vinegar.


Propagation


Requirements
The first consideration when attempting to cultivate grape is to select a variety based on the prevailing local climate, with the best production occurring in hot, dry regions. American varieties tend to be the most cold hardy while the European hybrids perform best in hotter, drier regions. Generally, vines should be grown in full sun, in a well draining soil and in a location where there is good circulating air to reduce incidence of disease. Low lying areas should be avoided when selecting a planting site as this can lead to water accumulation during periods of wet weathe Vines prefer a soil with a slightly acidic to neutral pH between 6.0 and 7.0 and require a trellis system to support the weight of the fruit on the vines.

Preparation
Grape vines are usually planted as dormant bare root vines in Spring. Young plants can be purchased from nurseries and garden centres for planting in the home garden. Grape vines require a trellis and this should be built before the vines are planted in the ground. For information on constructing a suitable trellis see: https://www.plantvillage.com/posts/19....
The trellis helps support the weight of the fruit and protects the vines from damage while aslo increasing air circulation and reducing diseases in the canopy. You may also consider a more decorative method of supporting the vines, such as an arbor.

Planting
New vines should be planted out in Spring after all danger of frost has passed. Dig a hole for each plant approximately 30 cm (12 in) deep and 30 cm (12 in) wide, spaced 1.8– 3.0 m (6–10 ft) apart and plant the vine at the same level as the nursery. It is important not to cover the graft union in soil. Tamp the soil around the plants and add any remaining soil. The newly planted vines should be cut back to have only 2 or 3 new buds and watered lightly.

Training
In order for grape vines to develop strong root systems and support heavy loads of fruit, new vines should not be allowed to produce fruit for the first 2–3 years after planting. The vine will produce new shoots, of which several should be allowed to grow while the others are cut back. This allows the vine to fill out with leaves which provide energy for an extensive root system. The new shoots should be attached to the trellis. At the beginning of the second year of growth, select 2–3 of the strongest canes on each plant and cut back the rest. Allow 3 or 4 shoots to develop on each cane and attach to the trellis. Remove any flower clusters that form.

Pruning
Pruning is an essential component of healthy grape production and should be carried out annually in early Spring while the vines are still dormant and before the buds begin to swell. From the third year onwards, most of the previous years growth should be removed. The more buds that are left on each shoot, the more fruit it will produce but care must be taken to ensure that too many are not left as the fruit may not ripen as a result. Fruit clusters can be removed as required throughout the growing season.



References

CABI Crop Protection Compendium. (2014). Vitis vinifera datasheet. Available at: http://www.cabi.org/cpc/datasheet/56504. [Accessed 12 December 14]. Paid subscription required.

Lord, W. (2001). Growing Grapes. University of New Hampshire Cooperative Extension. Available at: http://extension.unh.edu/resources/fi.... [Accessed 12 December 14]. Free to access.

Pearson, R. C. & Goheen, A. C. (Eds.) (1988). Compendium of Grape Diseases. American Phytopathological Society Press. Available at: http://www.apsnet.org/apsstore/shopap.... Available for purchase from APS Press.

Strick, B. C. (2011). Growing Table Grapes. Oregon State University. Available at: http://smallfarms.oregonstate.edu/sit.... [Accessed 12 December 14]. Free to access.


Common Pests and Diseases

Pierce's disease
Xylella fastidiosa

Symptoms
Yellow to red leaf edges; dry leaves with leaf death in concentric rings; leaves dropping but petiole remaining attached to vine; fruit dry and shriveled
Cause
Bacteria
Comments
Disease transmitted by sharpshooters and spittlebugs
Management
Application of appropriate insecticide in areas adjacent to plantation can help reduce the number of sharpshooters reaching vines in spring; remove symptomatic vines while dormant; monitor vines with mild symptoms and remove when symptoms become pronounced

Crown gall
Agrobacterium vitis

Symptoms
Galls on vines; wilting and yellowing of canopy; drying grapes; collpsing plants
Cause
Bacterium
Comments
Bacteria enter via wounded areas; spread from infected rootstock
Management
Sanitize all equipment regularly; avoid injuring plants; plant disease free stock, heat treatment of planting material can help eliminate pathogens prior to planting

Young vine decline
Phaeoacremonium spp.
Togninia minima,
Togninia californica

Symptoms
Small yellow spots between leaf veins; leaves dropping; round brown or purple lesions on fruit; dry cracked fruit
Cause
Fungi
Comments
Fungus can enter the plant through propagation wounds
Management
Avoid stressing vines; provide adequate irrigation and do not over-fertilize; do not harvest fruit until vines are at least 3 years old

Anthracnose (Bird’s eye rot)
Elsinoe ampelina

Symptoms
Dark red lesions on grapes; sunken gray lesions with a darker edge on grapes; lesions on the leaves causing leaf to curl; lesions on shoots may cause a ring of damage which will kill parts of the plant; lesions may also be present on tendrils, fruit stems, and leaf stems
Cause
Fungus
Comments
Disease favors warm weather
Management
Plant less susceptible cultivars; application of Bordeaux mixture or other appropriate fungicide while vines are dormant may be necessary

Armillaria root rot
Armillaria mellea

Symptoms
Weak, short shoots; white fungal mats under the bark at the soil line; unproductive vines; rapid wilting
Cause
Fungus
Comments
No known Armillaria resistant grape varieties
Management
Fumigation may be necessary in soils known or suspected to have carried the disease

Black rot
Guignardia bidwellii

Symptoms
Brown lesions on the leaves that develop black dots (pycnidia); grapes have light spots that eventually form pycnidia; grapes harden and turn black, while still remaining on the vine
Cause
Fungus
Comments
Disease favors rainy weather; spores may ooze out during rain
Management
Remove all mummified fruit from vines during dormant pruning; cultivate soil during bud break to bury mummies and reduce inoculant; application of appropriate fungicides can help control the disease

Botrytis bunch rot (Gray mold)
Botrytis cinerea

Symptoms
Brown lesions on the stem early in the season; grapes covered with a gray to tan powder; stems and grape clusters shrivel
Cause
Fungus
Comments
Disease favors high levels of moisture and high temperatures.
Management
Plant less susceptible varieties; reduce amount of vegetative growth on vines; do not over fertilize; use suitable trellises to increase air circulation in canopy and expose grape clusters to sun; disease usually merits chemical control

Dieback (Eutypa dieback.)
Eutypa lata

Symptoms
Stunted, withered leaves curled into a cup shape; dark cankers on wood; cross section of wood reveals wedge-shaped discoloration
Cause
Fungus
Comments
Affects older vines that are five to six years old
Management
No resistant varieties known; disease practically impossible to control without chemicals in areas where alternative hosts are available; use of an appropriate fungicide on pruning wounds can prevent the fungus from entering the plant; fungicide should be applied at time of pruning

Powdery mildew
Erysiphe necator

Symptoms
Red patches on canes; yellow patches on top surface of leaves; white powdery growth on leaves; white powdery growth on fruit
Cause
Fungus
Comments
Disease favors mild temperatures and high humidity
Management
Plant vines in sites with good air circulation and sun exposure; use a training system that promotes air circulation through the canopy; apply sulfur or copper based fungicide

Leaf spot (Phomopsis cane)
Phomopsis viticola

Symptoms
Dark lesions with yellow edges on canes and leaves; canes appear bleached and may have dark discoloration; small distorted leaves; lesions in shoots cause cracking
Cause
Fungus
Comments
Disease emergence favorable with rain directly following budbreak
Management
Use pathogens free planting material; if disease is present prune out dead and infected wood and plow under soil; apply an appropriate fungicide

Esca (Black Measles or Spanish Measles)
Phaeomoniella aleophilum, Phaeomoniella chlamydospora

Symptoms
Symptom appears on leaves, trunk, canes and berries. On leaves we will see intervenaial striping looks like tiger strips. White cultivars shows chlorotic and necrotic strips where as red cultivars shows red areas and necrotic strips.
On berries we will see superficial spots and later may coalesce making berries appear black. Trunk/arm/cordons shows dark brown black vascular streaking and oozes dark sap when we cut trunk. Some time this measles in associate with numerous secondary wood rotting fungi which decorate the vineyard completely.
Cause
Fungus
Comments
The leaf and berry symptoms may occur together in single cane or may show symptom on only one parts. The severe infestation of measles kill grapevine in a single year which is commonly called apoplexy.
The symptoms are common in 5 to 7 year old vineyard. The prune wounds helps in pathogen entrance and establishment.
Management
Till date there is no effective method to control this disease. Remove the infected berries, leaves and trunk and destroy them. Protect the prune wounds to minimize fungal infection using wound sealant (5% boric acid in acrylic paint) or essential oil or suitable fungicides.

Leaf blight (Isariopsis Leaf Spot)
Pseudocercospora vitis

Symptoms
On leaf surface we will see lesions which are irregularly shaped (2 to 25 mm in diameter). Initially lesions are dull red to brown in color turn black later. If disease is severe this lesions may coalesce. On berries we can see symptom similar to black rot but the entire clusters will collapse.
Cause
Fungus
Comments
Common in tropical and subtropical grapes. The disease appear late in the season. Cynthiana and Cabernet Sauvignon are susceptible to this pathogen.
Management
Fungicides sprayed for other diseases in the season may help to reduce this disease.

Black vine weevil
Otiorhynchus sulcatus

Symptoms
Feeding damage to stems, leaves, buds and/or flowers; loss of plant vigor
Cause
Insect
Comments
Larvae live in soil and feed on roots
Management
Consider growing a cover crop such as red fescue

Grape cane girdler
Ampeloglypter ater

Symptoms
Holes encircling cane; punctures in cane
Cause
Insect
Comments
Greatest injury to vines during establishment
Management
Prune out infested shoots below girdle before adult insects emerge in summer; spraying me be required to control adult populations

Grape mealybug
Pseudococcus maritimus

Symptoms
Sooty mold growing on fruit
Cause
Insect
Comments
Sporadic pest; sugary secretions by the insect drop onto fruit and encourage growth of mold
Management
Control ant populations to encourage populations of mealybug natural enemies; apply appropriate insecticide

Japanese beetle
Popillia japonica

Symptoms
Leaves skeletonized (only veins remaining); flowers and buds damaged; plant damage may be extensive; adult insect is a metallic green-bronze beetle with tufts of white hair protruding from under wing covers on each side of the body; adult beetles are approximately 13 mm in length; larvae are cream-white grubs which develop in the soil
Cause
Insect
Comments
One beetle generation every 1-2 years; pheromone traps may actually attract more beetles to home gardens and should generally be avoided; beetle overwinters as larvae in soil; beetle has an extensive range of over 300 host plants
Management
If beetles were a problem in the previous year, use floating row covers to protect plants or spray kaolin clay; adult beetles can be hand picked from plants and destroyed by placing in soapy water; parasitic nematodes can be applied to soil to reduce the number of overwintering grubs; insecticidal soaps or neem oil can help reduce beetle populations