Growing Grapes in WV - West Virginia Department of Agriculture

Growing GrapesIN WEST VIRGINIAW e s t V i r g i n i a D e p a r t m e n tof Agriculture

Growing Grapes inWest VirginiaGrapes are grown in West Virginia in small-scale commercial andbackyard plantings. The increased interest in grapes for table and wineproduction has led to increased research and cultivar selection by theDivision of Plant and Soil Sciences of the West Virginia University DavisCollege of Agriculture, Forestry and Consumer Science. With carefulplanning and management, grapes can be grown in West Virginia forhome or profitable commercial use.Types of GrapesThere are several hundredwidely different cultivars of grapesgrown in the United States. Thecultivars are grouped into fourtypes: (1) European (Vitis vinifera),(2) American (Vitis labrusca and itsderivatives), (3) Muscadine (Vitisrotundifolia) and (4) French hybrids,crosses of V. vinifera cultivars withdisease-resistant wild Americanspecies.The European grape has beendifficult to grow in West Virginiabecause it is very susceptible tocold injury and requires long, warmsummers for proper fruit maturation.Disease and insect susceptibilityare also serious problems withV. vinifera types. With proper siteselection and training systems toallow recovery from winter damage,European grapes can be grownin some areas of West Virginia.Wineries prefer vinefera grapes forwine production and will often pay apremium price for them.-1-The American grape typified bythe cultivar Concord is winter hardyand disease resistant. Americangrapes are the most commonlygrown grapes east of the RockyMountains. Many new cultivars ofexcellent seedless table grapes,very different from Concord, havebeen developed.Muscadine grapes are mostcommonly grown in the southbecause they are only hardy whereotemperatures rarely fall below 10 Fo(-12 C). Few places in West Virginiameet this requirement. The fruitand culture of Muscadine grapes isdifferent from other grapes and willnot be covered in this paper.French hybrids are usuallysuperior to American types forwine and are more cold hardy anddisease resistant than Europeantypes. Several of these cultivarshave been tested in West Virginiafor their adaptability to easternclimatic conditions (see section oncultivars).

Locating the VineyardProper site and soil selectionare critical to good production.The prospective grape grower isin most cases already on a farmand has little if any choice in thegeneral location for a vineyard,but the grower may have severalpossible sites available onthe farm from which to choose.The vineyard should be locatedaway from natural woodlands, ifpossible, to reduce infestation byinsects and damage by birds anddeer. It is important that the sitehave good air and water drainage.The slope should be gentleenough to allow easy cultivationand spraying without erosion. Alevel piece of land with lower landnearby so that cold air can drainoff, or a site that has a slope of2-3 feet in each 100 feet is ideal.Steeper sites should be plantedwith rows following the contour.Good air drainage is more essentialwith grapes than with othersmall fruits because, in additionto possible frost injury, infectionby such fungus diseases as blackrot is more severe where airdrainage is poor.The most desirable exposuremust be decided by the individualgrower. A southern exposuregives an earlier crop but increasesthe danger of injury to the tendershoots from late spring frost.A northern or eastern exposurereduces the risk of frost but givesa later crop. The grower mustdecide if the slightly earlier cropis worth the risk. Market demandswill be an important considerationin making the choice.A gravelly or sandy loam soilis considered best for grapes,but they will do well on many soiltypes. The soil should have afairly high water-holding capacity,not be waterlogged at anytime during the year, have 3 to 5feet of usable depth dependingon texture, be of at least mediumfertility and slightly acid. A soil toopoor to grow other crops will notbe satisfactory for a vineyard. TheSoilprospective grower should keepcertain general characteristics ofsoils in mind in choosing a site.A sandy soil warms up rapidlyand will mature a crop a few daysearlier than will a clay soil but asandy soil tends to be less fertileand to have a smaller water-holdingcapacity. A soil containing toomuch clay will also form a crustin hot weather that will adverselyaffect water infiltration.-2-

In selecting a grape cultivar,you must consider the number ofgrowing degree days, the lengthof the growing season and thefrequency of exposure to lowtemperatures. The time requiredto mature grape fruit varies withlocation and climate and is verydependent on the amount of heatexperienced by the vine. Thefrequency of very cold weatherwill determine winter survival ofthe vines.The growing degree day(GDD) is used to calculate theamount of heat received. It iscalculated as the daily averagetemperature (max + Min/2) minusothe base temperature of 50 Fbelow which grapes will not grow.During a spring day with a highooof 80 F and a low of 60 F, theGDD+((80+60)/2)-50=20. Theowhole month of average 70 Fweather would be equal to 600GDD (30 days x 20=600). YouRegion GDD CultivatarsTemperaturecan approximate the number ofGDD from the closest weather reportingstation (see appendix 1).For every 100 feet elevation, theGDD decreases by approximately70 for a season. If a nearby townexperiences 3000 GDD in a yearand your vineyard is 200 feethigher, then your vineyard wouldhave approximately 2860 GDD(3000-(70 x 2)).In general a frost free periodof 165-180 days is required tomature grape fruit and wood. Theperiod must be long enough toallow harvest of the fruit and timefor the wood to acclimate for thewinter. The length of the growingseason is not as important asthe GDD in determining cultivaradaptability, as some areaswith long seasons are not warmenough to mature grapes well.Wine growing regions are dividedinto five zones based solely ontheir GDD accumulations:Table 1. Wine growing regions, their GDD and typical cultivars.I >2500 Chardonnay, Pinot, Noir, White Riesling, Foch,Cayuga, White, most American typesII 2501-3000Above cultivars and Chambourcin, Chenin Blanc, CabernetSauvignon, Gamay, Seyval, Vidal 256III 3001-3500IV 3501-4000V >4000 Thompson Sdls.Chenin Blanc, Refosco, Zinfandel, Seyval, Vidal 256Dessert wines, table grapes, raisin grapes-3-

Table 2. The expected ten-year frequency of cold temperatures relatedto winter damage hazard.Minimum Temperature-5 -10 -15Winter Damage Hazard

Hardwood CuttingsHardwood cuttings are themost common method of propagation.Cuttings can be made atany time after leaf drop in the falluntil the sap starts to flow in thespring. If the cuttings are preparedin fall or early winter, there is abetter chance of obtaining goodcallus formation that is critical torapid root formation in the spring.However, good results are sometimesobtained by making cuttingsa week or two before the sap risesin the spring and setting them outimmediately.Straight, vigorous, wellmatured,one-year-old canes withwell-developed buds should bechosen for cuttings. The best cuttingsare made from canes aboutpencil-size or slightly larger withfour buds 2-3 inches apart. Thismakes an ideal completed cutting8 or 12 inches long.In making the cuttings, aslanting cut should be madejust below the lowest bud, and astraight cut should be made aboutone inch above the top bud sothat the top can be easily identifiedand the bud will not dry out.Rooting takes place more readilynear buds than on other parts ofthe cane. Usually about 50 percentof the cutting will root so takemore than are required.The completed cuttingsshould be grouped according tolength and tied in bundles of 50with the butt ends together. A fungicidedip is not essential but maybe used to prevent mold during-5-storage. They should be clearlylabeled, buried in trenches in awell-drained spot, butt ends up,and covered with 3 to 6 inches ofsoil. Inverting the cuttings inducescallusing of the butt end whilethe top remains dormant. Afterthe ground freezes, a coveringof straw or manure will preventalternate freezing and thawingwith changes in temperature. Thecovering should be removed assoon as the weather warms inthe spring.As soon as the ground hasbecome warm in the spring andthere is no danger of frost, thesoil should be prepared carefullyto a depth of 8-12 inchesand the cuttings set about 5-6inches apart in the row and deepenough so that only the top budprotrudes above ground. Thesoil should then be firmed wellaround the cutting. Weeds shouldbe controlled by hand, with herbicideor black plastic. Irrigationis useful and required in mostyears. If plastic is used, preparethe soil in ridges, cover with plasticand plant the cuttings throughthe plastic. Rooted cuttings canbe dug in the fall, graded andstored either by setting the rootsin a trench in well drained soil orstoring under moist conditions ato34 F.Layering &GraftingLayering and graftingare sometimes used in grapepropagation. Layering is usedfor certain varieties that do notroot readily from cuttings and

for filling in vacancies in anestablished vineyard. Grafting ispracticed chiefly by nurseries toestablish a cultivar on a differentrootstock and will not be describedhere.In layering varieties that donot root readily, a narrow trenchabout 10-15 inches deep is dugin early spring where the newplant is desired or where there isroom to produce a nursery plant.A healthy cane of the previousseason’s growth, originatingclose to the ground on aneighboring vine is bent downto the bottom of the trench andvertically back up to bring twoor more tip buds above the soilsurface. Wounding the caneopposite each underground budwill hasten rooting. The trench isthen filled to promote rooting ofthe cane section below ground.The part of the cane connectingthe new plant to the mother plantshould be stripped of developingshoots as they emerge. Onlythe shoots from the buds of theprotruding cane tip should be allowedto grow. The rooted plantscan be severed from the parentvine the following spring and setin their permanent location. If therooted plant is to fill the vacancywhere it is rooted, the plantshould not be severed from themother plant until the diameter ofthe new vine trunk exceeds thediameter of the bent over caneand fruit should be removed forthe first two years.RootstocksGrapes can be grown on theirown roots or grafted onto a plantthat provides special root characteristics.The primary reasons forusing a rootstock are to provideresistance to phylloxera andnematode parasites on the rootsystem, to isolate the scion cultivarfrom soilborne virus diseases,to induce vigorous growth in areplant situation, and to avoidvarietal susceptibility to limeinducedchlorosis. If any of thesesituations apply to the plannedvineyard site, rootstocks shouldbe considered.CultivarsGrape cultivars tested inWest Virginia are listed in Table3 pages 24-27. Because ofthe diversity of climate in WestVirginia, it is suggested that anycultivar to be planted should betried on a trial basis first. Inclusionin this table is not an indicationthat the plants will survive inall locations.-6-

Planting the VineyardSoil PreparationA well-cared-for vineyardwill often outlive the person whoplanted it. Hence, adequate soilpreparation is very important. Thispreparation should begin at leasta year before the vineyard is tobe set out. It should be designedto subdue weeds, to improve thephysical condition of the soil, andto add humus. This is easy to dobefore the vineyard is establishedbut is difficult to do after the vinesare in place. A soil sample shouldbe taken to determine potassium,magnesium, soil pH and organicmatter so that adjustments can bemade before planting. The need forkeeping a relatively high organicmatter content in the soil cannotbe overemphasized. A high humuscontent not only is essential forholding moisture, but it also improvesthe physical condition of thesoil. The growing of a short seasoncrop requiring constant cultivation,followed by a fast growing covercrop to be turned under, and augmentedby the addition of as muchbarnyard manure as possible willput the soil in a desirable state oftilth. Part of the manure can be puton the cultivated crop in the spring,the remainder in the fall. Leave acover crop on through the winterand turn it under in early spring.Before setting out the vineyard,poorly drained spots that show upwhile the cultivated crop is on theland should be drained. If the soilis sufficiently acid to require liming,i.e., too acid for cover crop growth,lime should be applied about a yearbefore planting. Troublesome perennialweeds such as quackgrassor morning-glory should be eliminatedwith herbicides before plantinggrapes. If grapes have been grownin this site before, at least two yearsof planting to grass or cover cropsis required to reduce the populationof grape root pests. Alternatively thesite could be fumigated or vigorousrootstocks used to avoid replantgrowth suppression.LayoutSeveral factors must be consideredin deciding on the bestplanting distances for a vineyard.First, there should be enoughspace between rows to allow forconvenient tractor cultivation andspraying; second, there shouldbe enough space between plantsin the row so that adjoining vineswill not intermingle too much; andthird, sufficient space should beallowed so that there will be littlecompetition between the roots ofadjoining plants for nutrients andwater. Vines are generally set 6-8feet apart in rows 9 feet apart. Atthe 8 feet spacing, 605 plants peracre will be required, at 7 feet, 690plants and at 6 feet, 807 plants.The first step in preparationfor planting is the laying out ofthe vineyard. Probably the bestmethod for laying out a small-7-

or medium vineyard is to use awire or cord marked by a knot atthe desired intervals. By simplymoving the ends of the line overthe distance between rows, smallmarking stakes can be driven atthe knots and the vineyard laid outquickly. Some growers prefer tomark off the outside rows with fivetosix-foot uprights, turn furrowslengthwise and across the field,and set the plants at the intersectionsof these furrows. Othersprefer to sight between outsidestakes. Whatever method is used,it is essential that the vines be setin sufficiently straight rows so thatthey will not interfere with culturaloperations after the trellis is inplace. Adequate headland must beleft at each end of the site for trellisanchoring and equipment turning.The rows should run northand south unless there is a goodreason for doing otherwise. Thiswill lead to better light exposure,drying and disease control. Therows should not run at right anglesto strong prevailing winds thatmight cause damage by whippingthe shoots about. The vines shouldfollow the contour of a fairly steepsite, or at least run across the hillrather than up and down.At convenient intervals a rowshould be left out to form an alleythat will facilitate harvestingand cultural operations. The alleyshould divide the vineyard intoblocks about twice as long as theyare wide. If the field is long, 25-footcross alleys at 1,000 foot intervalsare also desirable to facilitate harvestingand fertilizing.In West Virginia, grapes should-8-generally be set in early spring toavoid winter kill of fall set plants.Care should be taken to see thatthe plants do not dry out. Whenthe plants are received from thenursery, the bundles should beopened and the roots soaked forseveral hours if they seem dry. Ifthe ground is not prepared andcannot be prepared within a dayor two, the young vines should beheeled in or held under refrigerationuntil ready for setting. Whencarried to the field, they should bekept in a pail of water or a wet sackand should not be dropped far infront of the planters. Damaged andexcessively long roots should bepruned back before a vine is set.A crew of four persons shouldbe used for setting grapevines ifpossible - two to dig holes, one tohold the vine and tamp the soil,and one to backfill. The holesshould be wide enough so that theroots can be spread out and deepenough for the vine to stand a littledeeper than it did in the nurseryrow. Make sure the graft union isabove ground if grafted plants areused. A little surface soil should beplaced around the roots in the bottomof the hole, and the soil shouldbe firmed as the hole is filled into ensure good root-soil contact.Fertilizer should not be placed inthe holes. After planting and afterdanger of frost, the vine shouldbe pruned to one strong, two-budcane.Most grapes are self-fertile andbear well in isolated blocks, but afew, for example Brighton, requireinterplantings of pollinizers suchas Concord.

Weed ControlGrapevines are more shallowrootedthan trees. Consequently,they are more affected by competingweeds. To get the early vine growthneeded for best yields, cultivation orherbicide strips are an establishedpractice in commercial vineyards.The timing of weed control orcover crop reduction between rowscan be used as a tool to influencevine growth. Weed and cover cropgrowth reduce water availability tothe vine and slow vine growth. Reducingweed and cover crop growthstimulates vine growth by increasingsoil water availability. Clean cultivationwill also increase temperaturesaround vines on frost susceptiblesites.Several herbicides are registeredfor use on grapes. Thereare three basic types of herbicidesused: residual, soil-actingtypes such as simazine, contactherbicides such as paraquat andsystemic herbicides such as glyphosate.Residual herbicides areused to control weeds before theygerminate. Contact and systemicherbicides are used to control establishedweeds. Care must be taken toavoid applying herbicides to foliage.Consult your West Virginia UniversityExtension Service specialist orcounty agent and the herbicide labelfor details and recommendations.Cover CropsVineyard Soil Culture-9-One of the serious problemsin the grape vineyard is the maintenanceof the humus supply. Annualcover crops will help to maintainthe organic matter in the soil.Humus may also be increased byapplying barnyard manure, wastehay, straw and pomace plus stemswith the chopped prunings.A cover crop lessens soilerosion and the leaching of valuablesoil nutrients and it promotesearlier hardening of wood in shortseasonlocations. In the bearingvineyard the cover crop shouldbe sown at the last cultivation inAugust. Domestic rye grass, rye,wheat, barley and vetch are commonlygrown. If the cover crop issown under the trellis, perennialssuch as rye may become a weedproblem. Cold-susceptible coversare useful in these situations.Complete commercial fertilizersmay be used to get a goodcover crop. An application of100-250 pounds of a 10-20-10fertilizer per acre is recommendedfor small grains such as rye, and150-200 pounds of a 0-20-10fertilizer for legumes.The Hillside VineyardA system of clean cultivationis difficult to carry out in vineyardlocated on hillsides. Some earlyspring cultivation may be given insuch vineyards if rows have beenlaid out on the contour system andif some terracing was done. If muchsoil erosion occurs, mowed sodcover should be planted every rowor every alternate row dependingon vine size and vigor. Within therow the soil should be cultivated or

weeds controlled with herbicides.The more sod, the greater thereduction in vine growth. On lesssteep slopes, trashy cultivation maybe the best alternative. In this methoda disc or rotary mower is runthrough the vineyard often enoughto keep the weeds and grass fromcompeting with the grapes, but theground is never left bare. In general,fruit production will not average ashigh from hillside vineyards as fromthose on more level land becauseit is more difficult to thoroughlycultivate hillsides. Where mulchingmaterials are cheap and plentiful,mulching may be the best methodof soil management in hillside vineyards.FertilizerSoil fertility should be determinedfrom soil sample analysisprior to planting. After planting, soiltests are not a dependable methodof identifying nutrient deficiencies.The nutritional status of the vinescan best be determined from petioleanalysis after planting. Petioles (leafstems) are collected from the youngestmature leaves of exposed bearingprimary shoots during August.They sample should reflect typicalvines. If some vines are showingsymptoms of nutrient deficiencies,these should be sampled separately.Contact the extension agent orspecialist for further information oncollecting petiole samples. A historyof fertilizers applied and petioleanalysis results are useful in decidingon future fertilizer applications.Soil fertility in the vineyard maybe best maintained by the use ofmanure and pomace when used atrates of 5-15 tons/acre. Some formof commercial fertilizer should be-10-used if there is insufficient manure.Nitrogen is generally the elementlacking; hence, marked responseswill be obtained by applications ofurea, ammonium sulfate or ammoniumnitrate. Cost per unit of nitrogenshould determine the selection ofthe form used. Forty to 60 pounds ofactual nitrogen per year is a generalrecommendation, and applicationsshould never be greater than 80pounds actual nitrogen per year. A200-300 pound application of ammoniumsulfate per acre (about onehalflb. per vine) made in the springis an average recommendation forvine maintenance on high-lime soils.Nitrogen fertilizer should be applied2-3 weeks before the anticipated budbreak so that there is sufficient nitrogenin the plant for strong growthat bud break. After establishmentof vine size, apply fertilizers only asrecommended by tissue analysis.Complete fertilizers should beused on the cover crop only, as potassiumand phosphorus need onlybe applied to the grapes when testsindicate they are lacking. Potassium,magnesium or manganesedeficiencies should be corrected assoon as discovered with rates of fertilizerdetermined by the severity ofthe symptoms. Petiole analysis candetect incipient deficiencies so theycan be corrected before symptomsappear.In new plantings, a fertilizersuch as ammonium sulfate shouldbe spread uniformly in a circulararea around each vine, startinga few inches from the trunk andextending out to a distance of a fewfeet. Broadcast applications maybe used after the first year, as vineroots extend throughout the soilvolume.

Training and PruningBefore attempting to train or prune a grapevine, certain principlesmust be understood to achieve the desired results. Pruning is the removalof wood to regulate fruit production. Training is the removal of wood insuch as way as to shape the vine so that it will bear a good crop withoutbreaking and will not interfere with cultural operations.Grapes are vigorous plants that require the removal of 80-90 percentof the new wood after establishment to balance fruiting and vegetativegrowth. All pruning should be done while the vines are dormant, preferablya short time before the sap begins to circulate in the spring. Winterinjuredwood may then be identified and removed.Training Young Vinesping. If vines do not produce 3/4pounds of prunings, the recom-First year: Prune back to fourmendations for the second yearbuds at planting. After danger oftraining should be repeated.frost, cut back to two living buds.A second cane originatingSecond year: During thefrom the very base of the vine candormant season following the firstnow be retained and pruned to thegrowing season, a single goodbottom wire if a double trunk sys-cane should be chosen to formtem is desired for areas with fre-the main trunk and attached toquent winter injury. In these areasthe top wire if possible. When thethe training systems are done withbuds burst, 6 to 10 shoots shouldtwo trunks. If one trunk is killed bybe retained on the upper portionwinter injury, mechanical damageof the trunk if training systemsor eutypa dieback disease, it cansuch as umbrella Kniffin, Hudsonbe removed with little effect onRiver umbrella, or Geneva doubleproduction. During the third grow-curtain are being considered, oring season, all but two or threeat the proper position for arms orshoots near the top of this caneother training systems. All othershould be removed shortly aftershoots should be removed toshoot growth commences. In laterconcentrate growth in the canesyears this second trunk is pruneddesired for future training. Allas a mirror image of the otherflower clusters should be removedtrunk and both are considered asas they develop to allow the plantone plant in counting buds.to become established beforebearing a crop.PrinciplesThird year: Vines that produce3/4 pounds or more of pruningThe principles of pruningshould be balance pruned and indicate what wood to leave, howfruited in the third year. Flower much to leave, and where to leaveclusters should be thinned to one it on mature vines. In brief theyper shoot to prevent over crop-are as follows:-11-

1. The fruit is borne onshoots produced from oneyear-oldwood. One-year-oldwood is brown, reddish-brown,or gray, depending on thevariety, and the bark is tightand not peeling. The amountof wood older than one yearshould be kept to a minimum toform the framework for holdingthe fruiting wood.2. Severe pruning resultsin an excess of wood and littlefruit, although both berries andclusters will be large. Lightpruning results in the productionof little wood and a largenumber of small clusters ofsmall fruit. A balance betweenwood and fruit production isdesired to give a good cropof large clustered fruit andenough wood for good canesthe following season. The numberof buds to leave is cultivardependent. For most cultivars30 buds should be left for thefirst pound of one-year-oldwood prunings removed and10 buds left for every pound ofprunings after that. If you remove3 pounds of one-year-oldwood, then there should be 50buds left on the vine. These 50buds may be ten 5-bud spursor five 10-bud canes dependingon your training system.This allows a balance that willvary with the vigor of the plant.To do this, most of the woodis removed, leaving more thanyou think should be left. Afterweighing what has been taken-12-off, the buds remaining canbe counted and more woodpruned off to adjust the numberof buds remaining to fit the balancedpruning equation.3. The best canes to keepfor fruiting are those of mediumsize (about the size of a pencil)with plump buds. Canes with adiameter of one-fourth to onethirdinch and an internodallength of five to eight inches(internode lengths are shorteron vinifera and French hybridcultivars)-both measured betweenthe fifth and sixth nodesfrom the base - are consideredideal.4. The most productivebuds on the canes are cultivardependent, but generally thethird to ninth buds will produceshoots with the most flowers.5. The bearing wood shouldbe close to the main trunk.This saves space and limits theuptake of plant food by unfruitfulwood. Choose wood andrenewal spurs (canes prunedto 2-3 buds to provide canesfor fruiting the next year) closeto the permanent training structure.Permanent structuresinclude the main trunk andbranches (short arms or longcordons) that the fruiting woodoriginates from.Flower-ClusterThinningFlower-cluster thinning is theremoval by hand of some of theflower clusters on each shoot to

control crop load. This is mosteffectively done when the clustersfirst appear. Clusters are removedto increase the vigor of very weakvines and to reduce excessivecrops on vigorous vines. Early reductionin crop load will allow theremaining fruit to be larger, ripenearlier and have higher sugarsthan fruit on over cropped vines.Clusters are usually thinned toone cluster per shoot.Growth regulators are alsoused to control fruit size. Gibberellicacid is a natural plant hormoneusually produced by seeds. Mostseedless grapes respond togibberellic acid with an increasein berry size. In some cultivars,such as Canadice, the increasedberry size can result in excessivecompactness and berry cracking.Concord seedless also reactsunfavorably. Gibberellic acid isapplied at mid bloom and at fruitset, usually about 7-10 days afterbloom, to reduce berry numberand increase berry size.Seeded grape cultivars mayrespond to gibberellic acid withreduced cluster compactness andtherefore a reduction in bunchrot in cultivars with very compactclusters. In seeded grapes,gibberellic acid is applied whenshoots are 4 to 6 inches long.Consult the label before use becausesome seeded cultivars varyin their response to gibberellicacid. Misapplication of gibberellicacid can result in increased winterdamage and reduced bud fruitfulnessin the year following application.Label recommendationsshould be strictly followed.SystemsThere are many different waysto train grape vines. Research andexperience have shown that theJudson River umbrella or Genevadouble curtain are best for mediumto large vigorous vines of Concordand similar varieties. Four armKniffin, cordon and other trainingsystems are acceptable for smallervines. In choosing which system,several considerations should bekept in mind. Vines that are trainedon two wires, one above the other,will have less growth and loweryields on the lower wire becauseof shading from the canes above.Renewal spurs should be in highlight environments to produce goodcanes for the next year's crop.Cultivars with large leaves anddrooping shoots, such as Concord,Niagara, and Fredonia, should havethe head or renewal area of the vineat the top wire to get the best lightexposure. Cultivars with uprightshoots and small leaves can bettertolerate having the renewal areaat the middle wire of a three-wiretrellis because there is less shading.Cane bending as used in umbrellaKniffin will increase bud break alongthe canes or vigorous vines, butshould not be used with weak vinesof any cultivar. In all systems, thefoliage should be uniformly distributedalong the trellis and over itsfull height to a depth of not morethan one and one-half to two layersof leaves for effective exposure tosunlight.-13-

Geneva Double Curtain:This system utilizes a 4-footcross arm on the trellis todouble the amount of canopyper row and a single wireabout 3 feet high to supportthe trunk (Fig. 1). Vines aretrained to alternate sides ofthe 6-foot high trellis. Eachvine has a 6-8 foot cordon(permanent branch on eitherside of the main trunk,or trunks that is secured by two to four wraps around the support wirewith a wire tie at its end. Each cordon has 10-12 short (4-6 bud) canesevenly spaced along its length. A renewal spur should be kept as nextyear's replacement for each of the short canes.Four Arm Kniffin: This system utilizes two wires at 3 and 6 feet fromthe orchard floor (Fig. 2).At pruning, four canes andfour renewal spurs shouldbe retained. The canesshould originate a few inchesbelow the wire they are tobe trained on and be 8-12nodes long. Two to 6 canesmay be retained dependingon variety, can vigor and vinespacing.Umbrella Kniffin: This systemuses the same trellis as thefour arm Kniffin; however,the canes all originate fromthe head or top of the vine(Fig.3). The top of the vineshould reach to 6-12 inchesblow the top wire. From thishead region, one to six canesof 8-15 buds are bent sharplyover the top wire and tieddown to the lower wire. Each cane retained should have a renewalspur retained nearby on the head of the vine.-14-

Bilateral Cordon: This systemis similar to the Geneva doublecurtain only it is a single curtain(Fig. 4). In this system the mainvine is trained up to the top wireand two cordons are trainedout from it toward the adjacentvines. Each cordon is three tofour feet long and has 5-6 shortcanes or spurs that can besummer tied to the lower wireif needed. The cordon should also have an equal number of renewalspurs spaced along its length.Two-Wire Vertical Trellisfor GrapesThe basic two-wire trellis is 5feet high and is designed mainlyfor the four-cane kniffin system.Single-span brace or tie-backassemblies may be used. Wirespacing from the ground up is 30and 28 inches. Line post spacing is20 to 30 feet. High tensile 200,000PSI 12 1/2 gauge fence and trelliswire tensioned to a minimum of250 pounds can provide adequatesupport for trellis lengths up to4,000 feet. Properly constructedend brace assemblies are a mustfor any grape trellis, but becomemore important as the trellis lengthincreases.General trellis componentspecifications are given in Figure 5.The trellis can also be constructedwith different size posts, number ofwires and post spacings to accommodateheavier fruit loads.The end post in the tie-backbrace assembly is driven at aTrellising-15-30-degree angle from vertical, oppositethe direction of pull of theline wires. For a 58-inch high trellisa 4-inch diameter, 9 foot long postshould be used in unstable soil, an8 foot post in stable soil. The angleto drive the post can be determinedby setting the post vertically atground level and marking a 58-inchheight on the post. Attach a plumbline at this mark and lean the postuntil the plumb line is 32 inches(horizontally) away from the post.The post is driven at this angleuntil the top is 58 inches (vertically)above the ground.The 6-foot long x 4- to 5-inchdiameter tie-back post is drivenvertically to a 4- to 5- foot depth ata 28-inch horizontal distance fromthe plumb line location. With theline wires attached to the tie-backpost 6 inches above ground, theend post, top line wire and horizontalprojection of the two line wiresfrom the tie-back post towardthe end post form an equilateraltriangle.

-16-

Geneva Curtain-TypeTrellis for GrapesThe Geneva Curtain trellisis a three-wire T-shaped trellisdesigned for high production andmechanical harvesting, usuallyon relatively flat terrain. Singlespan brace or tie-back assembliesproperly constructed can supporttrellises up to 4,000-foot length.Line posts spaced 20-30 feet apart,depending on terrain, providesupport for the 12-1/2 gauge hightensile support wires.Wire spacing from the groundup for the vertical support wiresis 26, 26 and 20 inches. A 4-footlong cross-arm is used to supporttwo upper support wires placed 22inches out from the post. Theseupper support wires are at a72-inch height above ground. Allwires are tensioned to a minimumof 250 pounds. Line posts shouldbe placed closer together on rollingterrain to maintain a uniform wireheight.General trellis componentspecifications are given in Figure6. The trellis can be modified to accommodatedifferent requirements.-17-

HarvestingGrapes should be picked whenthe fruit reaches the desired ripenessfor its intended purpose. Asthe fruit ripens, the color changes,the sugars increase and the acidsdecrease. The timing will vary fromyear to year. Berries should besampled daily as the harvest approachesto determine sugar, acidand pH. To sample, randomly collect100 to 200 representative berriesfor each cultivar. Acids decreaserapidly under warm conditions andfruit quality can change rapidly.To harvest the grapes a grapeknife or harvesting shears are used.Hold the grapes with one hand andcut with a rapid upward cut awayfrom your hands and arms to preventinjury. Hand shears are saferbut are slower and more difficult touse. Do not jerk or pull clusters fromthe vine as this will crush some ofthe fruit. Discard all green, immatureor diseased fruit. Gently placethe fruit into harvesting lugsor boxes and handle as littleas possible. Take the containersinto the shade as soon aspossible to reduce fruit temperatures.Grapes should be takento the winery the same day theyare picked.Grapes will keep severalweeks after maturity on the vineor if picked and stored in a verycool, dry, well-ventilated place.As long as there is no droppingof the berries it is best to leavethe crop on the vines and pickas the market demands. Unlessweather is rainy, there will be nodeterioration. If well-protectedby foliage, grapes will standcold weather (but not a frost).However, birds and bees molestingthe crop must be consideredin the decision as to whether ornot the mature crop is left on thevine.Pest ManagementBirds are common problems in Shotguns are one methodvineyards. They may eat the entire of controlling birds, howeverberry or damage the fruit by clawing many birds are protected by law.or pecking. The severity of damage Gas exploders and electronicis related to cultivar, degree of ripeness,amount of foliage hiding the orchard frequently, have simi-noisemakers, if moved about thefruit and proximity to bird roosting lar effects. Other scare devicessites. Small isolated vineyards with such as hawk kits, scare eyes,early ripening cultivars are the most distress tapes and bird bombssusceptible to damage. Monitor bird can be used in combination withdamage as the fruit begin to change gas cannons to improve theircolor. Early detection is critical in effectiveness. Bird netting is thecontrol efforts. Many systems are most effective method for controllingbirds, but is expensive andavailable to control birds, but noneis completely successful.cumbersome.-18-

DeerIn areas with adjacent woodlands,deer can cause significant damage tothe vines and foliage. Many repellentshave been tried, but none iscompletely successful. Fencing is themost effective method of keeping deerout of the vineyard. There are severalfence design alternatives from lowcost electric spider fences, to 6 wireelectric fences or 8-foot high or highernonelectric fences. See “Deer and Agriculturein West Virginia,” Publication809-810, for more information.DiseasesBlack rot (Guignardia bidwellii)is the most important diseaseof grapes in West Virginia. Thefungus attacks the leaves, stemand tendrils in the spring. Earlysymptoms of the disease are smallbrown or black spots that cause noserious damage and are seldomnoticed. Later the fungus spreads tothe fruit, where it is still not noticeableuntil the berries are about halfgrown. Between this period and fruitripening the severity of the diseaseincreases very rapidly and the fruitfinally turns black and shrivels. Thedisease overwinters in those shriveledberries (mummies) and on thedead tendrils and canes, so theseshould be removed and destroyedat pruning time. Careful spraying willkeep this disease under control.Botrytis (Botrytis cinerea) is theother major fungus that will attackfruit. Infection first occurs duringflowering and is not apparent untillater in the season. Single berrieswill turn brown and rot. Sporemasses are a characteristic graythat will cover the affected area.Sporulation is enhanced by rain,-19-free moisture on the berries andhigh humidity (above 92%). Thefungus will not grow at temperaturesabove 94oF. The fungus overwintersin the infected berries or clustersand spores are spread by air aftermoist weather in the spring. Botrytisis best controlled by an integratedprogram. Reduce overwinteringinoculum by removing grape mummiesat pruning and discing themunder. Fungicides at bloom timeare most effective. Vines shouldnot be sprinkler irrigated once thefruit begin to ripen to avoid moistureon the berries. An open canopythat allows air circulation will alsokeep fruit drier and reduce infectionconditions.Powdery mildew and other fungusdiseases are controlled by fungicidesapplied at regular intervals.InsectsThe grape leafhopper (Erythroneuraspp.) is a small, light-green,sucking insect that can be found inalmost all vineyards from late Mayand early June until fall. Adults havered, yellow or black markings andoverwinter in dead grass, underleaves, or in rubbish piles. Theyemerge as soon as it is warm inthe spring. They live on strawberry,blackberry, and raspberry leavesuntil the grape leaves open. Theysuck the sap through the lowersurface of the leaves and causesmall, pale spots to appear. Whenthe insects are numerous, the leafhas a mottled appearance and mayeventually dry up and fall. Cleaningup rubbish piles and spraying willhelp control this pest.The grape berry moth (Endopizeviteana Clemens) is theworm usually found when grapes

are wormy at harvest time. It is adark-colored caterpillar. It passesthe winter in the pupal stage onfallen leaves. It emerges about thetime the grapes are blossoming.There are two broods. The first eatsthe stems and external portions ofthe young berries. The caterpillarsof the second brood live entirely inthe berries. They attack all cultivars.They are most injurious to thosecultivars that have compact clusterssince they tend to be protected insuch clusters and can feed readilyon more than one berry. Someof the injured grapes fall from theclusters; the rest must be discardedat harvest time. Spraying is the bestcontrol, but deep cultivation of theleaves in late fall or early springalso aids in control. For a few vines,it often pays to pick and destroy theberries infested by the spring broodand to rake and burn the leaves inthe fall to reduce the overwinteringpopulation. Populations may bemonitored with a commercially availablepheromone trap. Trichogramaminutum Riley is an egg parasitethat will provide some biologicalcontrol.The rose chafer (Macrodactylussubspinosus (Fabricius)) may bevery bad in some seasons, especiallywhere there is light, sandysoil nearby. It is a long-legged,yellowish-brown beetle about onethirdinch long. It may appear in vastswarms about the middle of June orearlier. It stays about a month andeats foliage of all kinds in gardens,vineyards and orchards. The larvaefeed on the roots of grasses in sandysoil. Consequently, if most of thesurrounding land is under cultivation,the number of chafers may bekept down. Cultivation also destroys-20-some of the pupae. Petal-fallsprays for grape berry moth willalso control rose chafers.The Japanese beetle(Popillia japonica (Newman))is a shiny metallic-green beetleless than half an inch long withcoppery-brown front wings. It isof considerable importance inparts of West Virginia. It usuallyappears between June 1 and 15,and may be present until mid-August or later. Grape leavesare among its favorite foods, andunless protected many of theleaves may be reduced to a lacelikeskeleton. The eggs are laid inthe soil in grassy areas and thegrubs develop there. The larvaemay be controlled by a bacterium,Bacillus popillae (milkyspore). This biological controlagent is applied to grassy areasto control large larval populations,but is not effective againstadults. Commercially availableattractant traps are generally notadequate to protect vineyards,but can be useful in monitoringpopulations. Insecticide applicationswill usually be necessary forcontrol of the adults.The Grape root borer(Vitacea polistiformis (Harris))can cause extensive damage toa vineyard before its presence iseven detected. Although inconspicuous,the larval feeding canresult in yield losses and deathof the vines. The borers, whichare white with brown heads andrange in size from less than aninch to two inches, feed beneaththe outer bark of the roots. Theadults, unlike most moths, flyonly during the day, and often escapeidentification because they

esemble wasps. Control of this pestis difficult because contact insecticidesare ineffective against subterraneanlarvae. An effective culturalcontrol method involves moundingsoil beneath vines after borers havepupated, and then leveling theridges in the fall or spring. Whenadults leave the cocoons they areunable to dig to the surface. Timingis important because if moundingis done too early the larvae merelytunnel up into the ridge beforepupating. Proper weed controlappears to be important in borermanagement because of increasedlarval mortality at the exposed soilsurface. Nitrogen fertilizer may helpthe vines overcome some of the effectsof damage.Other DisordersNutrient deficiencies canstunt, yellow, blacken, scorch orkill grape leaves. Symptoms canbe used to identify the deficientelement; however, petiole analysisis best used to confirm a suspectedsymptom. The extent of thedeficiency is gauged by the time atwhich the symptoms appear andby their severity. Growers shouldbe familiar with the leaf symptomsof deficiencies of nitrogen, potassium,magnesium, and manganeseand should closely inspect theirvineyards in late August or earlySeptember to determine whethersymptoms are present. Consultyour extension agent or specialistfor assistance in identification.Nitrogen deficiency is seenin reduced vine size and small,pale leaves. Potassium deficiencyis seen in interveinal or marginalchlorosis or both. With increasingseverity, marginal necrosis(scorch) develops. Magnesiumdeficiency appears first and ismost severe on basal leaves ofthe shoots. Magnesium deficiencyis usually indicated by chlorosisbetween the large veins; howeverthe veins remain green and thereis usually a thin line of greentissue at the margin of the leaf.When severe, the tissue betweenthe veins can become necrotic andeasily confused with potassiumdeficiency. Manganese deficiencyis indicated by intermittent interveinalchlorosis which is usuallymore severe on shaded leavesthan those in full sun.-21-

Table 3. Summary of grape cultivar characteristics in trial at Kearneysville, WV (1986-1989).Table 3A. Seeded Table CultivarsProductivity PruningBerries Ripening BlackRotCultivar Color Maturity Vigor Hardiness Clusters ClusterSizeBuffalo Blue 2+ 3 3 2 2+ 3 2 3 3 3Concord Blue 2+ 3 3 2+ 2 3 2 3 3 2Festivee Blue 1+ 2 1 2+ 2 2+ 3 2 2 2Blue 1+ 3 3 3 1 3 3 3 2 2White 1 3 3 1 1 2 2 1 2 2KayGreyRed 2 2 2 3 2+ 2+ 3 2 2 1-22-FredoniaMonticelloSt. Croix Blue 11 3 2 2 1 1 3 2 2 2Vigor: 1=weak Hardiness: 1=poor Clusters: 1=too tight, 2=loose,3=fullKey to Table:Maturity:1=early, 2=mid, 3=latePruning:1=short,2-either3=longProductivity:1=lowBlack Rot:1=highRipening:1=uneven3=uniformBerries:1=small,2=med, 3=largeCluster Size:1=small

Table 3B. Seedless Table CultivarsProductivity PruningBerries Ripening BlackRotCultivar Color Maturity Vigor Hardiness Clusters ClusterSizeCanadice Red 1 2 2 1 2 1+ 1 2 1 1Blue 2+ 2 2+ 2+ 2 2+ 2 3 3 2Concord,SdlsGlenora Blue 1+ 3 3 1+ 2+ 2 3 2 2 2Himrod Blue 1 2 1 2 2+ 2+ 2+ 2 2 2Interlaken White 1 2 2 3 3 2+ 3 2 3 2Lakemont White 1 2 2+ 3 3 2 3 3 3 2Remaily White 1+ 2 2 3 2+ 2 1+ 2 3 2-23-Romulus White 1+ 2 1 2 2 2 3 2 2 2Red 1+ 2 2 2 2+ 3 1 2 2 2SuffolkRedVenus Blue 1+ 2+ 2 1 2+ 2 3 2 2 2Vigor: 1=weak Hardiness: 1=poor Clusters: 1=too tight, 2=loose,3=fullKey to Table:Maturity:1=early, 2=mid, 3=latePruning:1=short,2-either3=longProductivity:1=lowBlack Rot:1=highRipening:1=uneven3=uniformBerries:1=small,2=med, 3=largeCluster Size:1=small

Table3C. Wine CultivarsProductivity PruningBerries Ripening BlackRotCultivar Color Maturity Vigor Hardiness Clusters ClusterSizeAurore White 1 2 2 3 2 2 1 1 3 1Baco Noir Blue 2 3 3 1 1 1 1 3 3 3Catawba Red 3+ 3 3 3 2+ 3 1+ 3 3 3White 3 3 2 3 3 3 1 2 3 3CayugaWhiteBlue 3 2+ 2 3 2 2 2+ 2 3 1White 3 1 1 1 1+ 1+ 2+ 2 1 1Chelois Blue 3 2 2 1 1+ 1+ 3 2 3 2Blue 3 2+ 2 3 2 2 2+ 2 3 1Gewurztraminer-24-Delaware Red 3 3 3 1 1+ 1 2 3 2 2White 3 1 2 1 1 1 2 2 1 1ChambourcinChardonnayDeChaunacCluster: 1=too tight, 2=too loose,3=fullVigor: 1=week Hardiness: 1=poorKey to Table:Maturity:1=early, 2=mid, 3=latePrunning:1=short,2=either3=longProductivity:1=lowBlack Rot:1=highRipening:1=uneven3=uniformCluster Size: 1=small Berries:1=small,2=med.,3=large

Table3C. Wine Cultivars cont.Productivity PruningCultivar Color Maturity Vigor Hardiness Clusters Cl.Size Berries Ripening BlackRotLeon Millot Blue 1+ 3 3 1 1+ 1+ 3 2 2 2M. Foch Blue 1 3 3 1 1 1 1 3 3 2Niagara White 3 3 3 3 2+ 3 3 3 3 3Riesling White 3 1 1 1 2 2 2 2 1 1White 1+ 2 2 3 2 1 3 2 3 1SeyvalBlancBlue 2+ 2+ 2+ 1 2+ 2 2+ 2 3 1Seyval14117Vidal Blanc White 3 3 2+ 3 2 1 2 2 3 1-25-Horizon White 2 2 2 3 2 2 3 2 2 1Vignoles White 2 2 2 1 1 1 2 1 2 1White 3 2 2 3 3 3 1 2 2 3VillardBlancVigor: 1=weak Hardiness: 1=poor Clusters: 1=too tight, 2=loose,3=fullKey to Table:Maturity:1=early, 2=mid, 3=latePruning:1=short,2-either3=longProductivity:1=lowBlack Rot:1=highRipening:1=uneven3=uniformBerries:1=small,2=med, 3=largeCluster Size:1=small

Appendicesw Weather stations are often located at airports or industrial areas thatmay be slightly different than town centers.x Years data indicates the number of years of collected data these calculationsare based on. The more years data, the better the accuracy.Use extreme caution when fewer than two years data used.y Growing degree days calculated with a base temperature of 50 F.z The average number of times these temperatures occur in 10 years.Use caution when calculations based on less than 10 years data.o-26-

Appendix 1a. Growing degree days and frequency of low temperatures from various weatherstations throughout West Virginia.w x y zStation Years Data GDD Average occurrence of low temperatures in 10 years-5 F -6 to -10 F -11 to -15 F

Appendix 1a. continuedw x yStation Years Data GDD Average occurrence of low temperatures in 10 years z-5 F -6 to -10 F -11 to -15 F

Appendix 1b. Growing degree days and frequency of low temperatures from various weatherstations throughout West Virginiaw x y zStation Years Data GDD Average occurrence of low temperatures in 10 years-5 F -6 to -10 F -11 to -15 F

Appendix 1b. continuedw x y zStations Years Data GDD Average occurrence of low temperature in 10 years-5 F -6 to -10 F -11 to -15 F

Appendix 1c. Growing degree days and frequency of low temperatures from various weather stationsthroughout West Virginia.w x y zStation Years Data GDD Average occurrence of low temperatures in 10 years-5 F -6 to -10 F -11 to -15 F

Appendix 1c. continuedStations w x y zYears Data GDD Average occurrence of low temperature in 10 years-5 F -6 to -10 F -11 to -15 F

Walt Helmick, Commissioner1900 Kanawha Blvd., EastCharleston, WV 25305www.wvagriculture.org