Crop Profile for Grapes in Tennessee
Prepared: May, 2002
General Production Information
State's ranking in national production of grapes: unranked
State's contribution to total US production of grapes: <1.5%
Yearly production numbers:
Total acres grown: 375
Total acres harvested: 345
Cash value: $625,000 (2000 crop)
% of crop destined for wine: 98% +
Production regions: all areas of the state
Grape production holds a very significant place in Tennessee's agricultural picture. In the search for alternative agricultural enterprises, grapes have found a place for numerous growers. Approximately 375 acres are currently devoted to grape production in Tennessee. Of this figure, 345 acres are bearing (1). The 2000 crop totaled 727.5 tons having a commercial value of $625,000. Over 98 percent of the Tennessee crop is marketed through wineries and the estimated value of the wines produced in 2000 is nearly $5.5 million, making wineries one of the best examples of value-added enterprises in the state. This figure was derived using a juice yield of 130 to 150 gallons per ton and a selling price of $10 per bottle of finished wine. Wineries have made an important contribution to the state by providing taxes on the wine and other items sold in the wineries, employment for many Tennesseans and a strong attraction of tourists.
Estimates place the cost of establishing a vineyard and caring for it until the first commercial harvest at $5,000 per acre or more. This figure does not include land charges, labor or irrigation costs, since most Tennessee vineyards are not irrigated at this time. Annual production costs average $1,500 to $1,800 per acre excluding harvest(2).
For American and French-American hybrids, the average yield per acre will be about 5 tons. Depending on cultivar, site and cultural practices, this figure may range from 3 to 9 tons per acre. Muscadines have the potential for yielding in excess of 10 tons per acre, however, winter injury to vines keeps this figure lower. Vinifera cultivars do not yield as high as other types of grapes. Production will average less than 1.5 tons per acre. Variation from year to year is quite high due to cold injury and disease pressure.
Commercial vineyards are fairly small, ranging from about one acre to thirty acres. New growers are strongly advised to start small and expand the size of the vineyard as their expertise and the market demand develops.
Grapes are produced throughout Tennessee, however, most of the vineyards are found in the eastern half of the state. American and French-American hybrid cultivars do well throughout the state and comprise over 90 percent of the grape acreage. While muscasdines are grown along the southern border, winter injury to vines is an annual threat. Vitis vinifera cultivars have not performed satisfactorily or consistently in the areas in which they have been tested. Cold injury, disease pressure, low yields and a strong demand for wines made from the other types of grapes combine to make plantings of V. vinifera modest in size. Even with the American and French-American hybrids, spring frosts, high levels of rainfall and hot, humid summers present challenges in the consistent production of high quality crops for the wineries.
Cultural Practices
Vineyard Establishment:
Many vineyards are established on slopes or elevated sites to reduce the potential for frost injury and disease. Shallow soils or those having poor internal and surface water drainage characteristics are avoided.
The first thing prospective growers are encouraged to do prior to planting the vineyard is to visit several wineries to ascertain what cultivars should be planted and what the demand for the crop might be when they begin harvesting commercial crops. Site selection and preparation should start at least six months to one year in advance of planting.
Several training systems are in use by Tennessee growers including the bilateral cordon, the umbrella kniffin and the Geneva double-curtain systems. In the first two systems, vines are generally set 8 feet apart in rows 10 to12 feet apart (544 and 453 vines per acre, respectively).
Since most vineyards are set on sloping land, the preferred vineyard floor management plan consists of a clean strip 4 feet wide under the vines and close-mowed sod between rows. This system provides some passive protection against frosts and enables better pest control. Sod cover between rows lessens the erosion potential within the vineyard and provides support for equipment. Although it may not be the ideal sod cover, tall fescue is the dominant grass used in vineyards. While it is vigorous and competitive with vines, it is easy to establish and to control with herbicides. Rows are planted across slopes as opposed to up and down the slopes to lessen erosion potential and to facilitate more precise application of pesticides. This floor management system is more conducive to mechanical harvesting which is being used by several producers.
The first commercial crop in the vineyard should be expected the fourth year following planting. A full crop can be expected the following year. While these goals have been reached in less time, the majority of the plantings follow this timetable.
Rooted cuttings are planted for American, French-American hybrid and muscadine cultivars. Grafted vines using either C-3309 or SO4 for the rootstock are suggested for V. vinifera cultivars. The newly set vines are pruned back to one cane having two buds prior to the onset of growth. The objective for the first year is to develop a straight trunk on the vine. To aid in accomplishing this, the new shoot growth is loosely secured to a stake set beside the vine or to a string tied to the trellis wire and the base of the vine. Semi-transparent polyethylene tubes are being used in several new plantings to encourage development of a straight trunk.
Control of vegetation around the vine is essential for good growth and to permit control of certain pests. One of the primary objectives of site preparation is control of noxious weeds in the site. If this has been done, the pressure from grasses and weeds is reduced considerably the first year, although some method of vegetation control will be essential. New vines should also be sprayed with fungicides and insecticides to control several potentially devastating pests. Once fruit is allowed to remain on the vine, generally the third growing season following planting, the pest control program needs to be expanded to that recommended for bearing vineyards.
Bearing Vineyards:
Consistent yields of high quality crops are the goals of grape growers. To accomplish them, timely production practices including pruning, fertilization, weed and grass control, insect and disease control practices, cluster thinning, shoot positioning and leaf removal must be carried out. Time of harvest is related to the cultivar and weather conditions that favor development of an ideal sugar/acid ratio for the type of wine being produced. The exact time of harvest is based on analysis of fruit samples by the winery.
Most pruning is done when vines are dormant. although delayed pruning and double pruning are becoming more common practices where time and labor availability permit. Fertilization of the vineyard is generally carried out in advance of bud break. The analysis of fertilizer materials used is based on pre- and post-plant soil testing and growth and yields from the previous year. Tissue testing is used primarily as a troubleshooting tool at this time.
Weed and grass control begins with the application of a tank mix of pre and postemergence herbicides prior to the start of growth. A second herbicide application may be needed by early to midsummer to maintain clean ground under the vines.
Insect and disease control begins with a dormant application of lime-sulfur for anthracnose. Timing, pesticide selection and rate are all based on information contained in Extension Publication 1197. "Commercial Small Fruit Sprays."(3) This publication is revised annually to reflect changes in pesticide availability and timing. Applications are suggested throughout the period of crop development and after harvest. The need for some applications are based on weather conditions that favor the development of certain pests while others are based on monitoring the vineyard and phermone trapping.
Canopy management practices, which may include shoot positioning and leaf removal will begin shortly after bloom and will continue up to within a couple weeks of harvest. These practices have been shown to have a positive impact on pest control and increased fruit quality.
Insect Pests
Insect pests cause fruit loss, foliar damage, and vector diseases.
Grape berry moth(Endopiza viteana)
Grape berry moth is a primary insect pest of Tennessee grapes. Infestations vary from vineyard to vineyard, within a vineyard, and from year to year. Potentially, infestation could affect 100 percent of the grape acreage. The grape berry moth overwinters in cocoons on the vineyard floor and in adjacent woodlots. The first generation emerges in June. The second generation appears in August. A third generation occurs in the South and occasionally in the North. The second generation causes the most damage by tunneling into and feeding on green fruit. A single larva can destroy two to six grapes in a cluster, and several larvae often feed on a cluster. Sprays should begin within three weeks of the appearance of adult male moths in pheromone traps, to target the egg hatch, or when scouting finds more than 5% larval damage to grape clusters. Insect damage usually causes less than 10% loss. But without control, damage will increase each year.
Destroying dead leaves in the fall or early spring kills overwintering pupae. Pheromone traps can be used in vineyards with a history of the pest. Egg laying occurs two to three weeks following the trapping of adult male moths. A protective spray at this time reduces or eliminates the need to spray later in the season. While pheromone rope ties can be used to disrupt male grape berry moths, vineyards should be over five acres. Therefore, most Tennessee vineyards would not be candidates for them.
Japanese beetle (Popillia japonica)
Grapes are a preferred host for the adult beetles. At this time, Japanese beetles are found throughout East Tennessee and most of Middle Tennessee. They have not reached West Tennessee at this time, however, they are moving further west in the state each year. All vineyards in the current range of Japanese beetles are infested.
Adults emerge from the ground and begin feeding in June and July. One generation hatches each season. Adults feed on leaves only. Damaged leaves have a lacy appearance. Depending on the vigor of the cultivar, the threshold for beginning spray applications will vary from 15 to 20 percent of the leaves. Without control, Japanese beetles can completely defoliate an entire vine. Premature leaf loss can adversely affect fruit quality, increase the vine's susceptibility to winter injury and reduce the vine's long-term productivity. Control is difficult to achieve since Japanese beetles will move into a vineyard from perimeter areas and quickly reestablish high populations in the vineyard following sprays. With the current presence of Japanese beetle in Tennessee, lack of control could result in a loss of approximately 35 percent of the state's crop.
Phylloxera (Daktulosphaira vitifoliae)
Two forms of the aphid-like phylloxera exist. The root gall form feeds on the outside of roots, causing galls or swellings. Most American and French hybrid varieties are resistant to the root gall form. Susceptible varieties (V. vinifera) are grafted onto a phylloxera-resistant rootstock. The foliar form occurs on the leaves and creates galls at the feeding sites. The foliar form causes the greatest problem in Tennessee vineyards, although damage is usually confined to small areas in the vineyard and may be regarded more as a curiosity rather than as a serious pest problem.
During various years, foliar phylloxera may be found in all Tennessee vineyards except those with only muscadine cultivars. Leaves heavily infested with galls can result in defoliation and retarded shoot growth. By the time galls are visible, control sprays are ineffective. Therefore, preventive spray applications are made at bloom or as soon as galls appear. Leaves must be 70% infested with galls before yield loss occurs. Failure to control leaf phylloxera would result in a loss of about 10 percent of the state's crop.
Grape flea beetle (Altica chalybea)
Although considered a minor pest, the grape flea beetle can pose a serious threat to developing buds on grapevines. Grape flea beetle is found across the state, but is not a problem every year. Overwintered beetles emerge and feed on buds in April. Adults chew holes in developing buds, killing the primary shoot, which reduces yield. Larvae and adults also feed on leaves but do not cause significant damage. Sprays should be applied when damage exceeds 4 percent of the buds. While cultivating between rows will destroy pupae, it will not control beetles entirely. In addition, virtually all Tennessee vineyards utilize a sod cover between rows so cultivation is not an option. Cleaning up brushy areas near vineyards will limit overwintering sites for grape flea beetles and reduce pressures during the growing season.
Grape Root Borers (Vitacae polistiformis)
Grape root borers have been found in every Tennessee vineyard where phermone traps have been used. Grape root borers will infest the root systems of vines causing a decline in vine vigor and productivity. They can kill vines, but more frequently will weaken them predisposing them to cold injury at temperatures well above that which would damage healthy vines. The grape root borer has a two-year life cycle, most of which is spent underground feeding on the root system of the vines.
Infestations most likely come from wild vines surrounding plantings. Effective control involves both cultural and chemical practices. In spring to early summer, larvae migrate to the upper 2 inches of soil and pupate. If soil is mounded several inches in depth around the base of vines after the pupae have moved up, it is possible to prevent emergence. Mounds must be removed later in the growing season. Mounding is expensive and timing is critical since mounding before the pupae have moved up will have little effect. Maintaining bare soil under the vines will help to control populations by reducing the number of adult egg-laying sites and, more importantly, increase mortality of newly-hatched larvae by increased dessication before they enter the soil. This practice is reinforced by using a directed insecticidal spray to the base of the vine to establish an insecticide barrier on the soil surface.
Grape root borers can infest all types of grapes. French-American hybrid cultivars appear to be more seriously affected by grape root borers than American cultivars. Phermone traps can be used in vineyards to monitor for the presence of grape root borers and to aid in determining the optimum time to apply chemical controls.
Chemical control of insects in grapes:
An air blast sprayer applies insecticides as cover sprays. Most are tank mixed and applied with fungicides on an as-needed basis.
PHI-Pre-harvest interval REI-Restricted-entry interval
Carbaryl (Sevin 50WP)
Target pests: grape flea beetle, grape berry moth, Japanese beetle
Acres treated: 100%
Frequency and rate: 4 lb./acre 2-3 applications
PHI: 7 days
REI: 12 hours
Azinphosmethyl (Guthion 50WP)
Target pest: grape berry moth
Acres treated: 80%
Frequency and rate1: 2 applications
Guthion 50 WP 1.5-2.0 lb/acre
PHI: 10 days
REI: 48 hours
Comments: Restricted use chemical. Do not use azinphosmethyl more than three times a season.
Phosmet (Imidan 50WP)
Target pests: grape berry moth, Japanese beetle
Acres treated: 50%
Frequency and rate: 1.33 -2.12 lb/acre as needed (higher rate used to control Japanese beetle)
PHI: 14 days
REI: 24 hours
Endosulfan (Thiodan 50WP)
Target pest: phylloxera (foliar form)
Acres treated: 50% as needed
Frequency and rate: 2 applications, at bloom and 2 weeks later
Thiodan 50WP 2 - 3 lb/acre
PHI: 7 days
REI: 24 hours
Comments: Endosulfan is the only insecticide labeled for control of the foliar form of phylloxera. Endosulfan can cause phytotoxicity in sensitive varieties.
Chlorpyrifos (Lorsban 4E)
Target pest: grape root borer
Acres treated: 50% as indicated by phermone trapping
Frequency and rate:Lorsban 4E - 4.5 pints per 100 gal. water, apply 2 quarts of spray solution directed to a 15 sq. ft. area around the base of each vine One application at least 35 days before harvest
PHI: 35 days
REI: 4 days
Comments: take care to avoid contacting fruit and foliage with the spray. Application should be made with a handgun at relatively low pressure.
Diseases
Diseases pose the single greatest threat to profitable grape production. Most fungicides are applied as preventive sprays since fungal diseases are nearly impossible to control once they have become established.
Black rot (Guignardia bidwellii)
Black rot is the biggest concern of grape growers in Tennessee. It has the potential for causing heavy crop losses each year. The fungus overwinters in mummies (dried, shriveled grapes) on the ground or vines. In the spring, rain releases and splashes the spores from the mummies onto the leaves, forming lesions that release spores which infect leaves and fruit all season. Growers use a spray schedule to control black rot, which also controls other foliar diseases. All cultivars are susceptible to black rot. Infection of the fruit occurs beginning after bloom and extending until veraison. Infected berries will shrivel and become hard, black mummies. Foliar infection, which appears as irregular necrotic areas on the leaf surface, can develop after veraison. Effective control depends on good vineyard sanitation including removing mummified fruit from vines and the vineyard floor. Pruning to promote good light penetration throughout the canopy will lessen infection pressure and enable better spray coverage resulting in improved control.
Downy mildew (Plasmopara viticola)
The fungus overwinters in leaf debris on the ground. Rain splashes the spores onto the grapevine. Infection can occur as early as bud break and continue throughout most of the growing season. Severe outbreaks may be seen in wet years. Leaves develop yellowish brown lesions on the upper surface and white patches on the underside. Severely infected leaves curl and drop. Young shoots, tendrils, and stems become distorted, thickened, or curled. White, cottony patches appear on fruit during humid conditions. Loss in yield can exceed 25 percent. Defoliation will adversely affect fruit growth and quality and increase vine susceptibility to winter injury. Infection can develop after harvest. The application of fungicides may be needed in many years
Powdery mildew(Uncinula necator)
Powdery mildew overwinters in bark crevices of the grapevine. Spores released by spring rains are the primary inoculum. Wind carries the fungus where it grows on any green surface of the vine. The infected area has a dusty or powdery appearance. Spores produced in infected areas provide secondary inoculum for infections throughout the growing season. French-American hybrid and European cultivars are more susceptible to powdery mildew than native American cultivars. Powdery mildew can be a problem in dry years. Powdery mildew infects all green tissue. Infected clusters drop blossoms before the fruit sets. Infected grapes split before maturity. Infected leaves have reduced photosynthetic capability which can reduce fruit quality. Wines made from grapes infected with powdery mildew may have an off-flavor. Early season control reduces the total number of fungicide applications. Susceptible varieties often require late-season sprays. Optimum temperatures for disease development are 68-77°. Careful use of sterol inhibitors is important to reduce fungicide resistance.
Phomopsis cane and leaf spot (Phomopsis viticola)
The fungus overwinters in lesions on 1- to 3-year old vines. Rain spreads the fungus to new shoots, leaves, and (later) developing grapes. Infected fruit appears similar to black rot. Heavily infected shoots are prone to wind damage. The fungus enters small green grapes but the disease is not apparent until close to harvest as the disease is not active during the warm summer months. As grapes ripen they become light brown and shrivel. The first scheduled spray application is to control Phomopsis. Yield is reduced because of fruit loss and weakened vines.
Botrytis bunch rot (Botryotinia cinerea)
Botrytis bunch rot, or gray mold, quickly spreads from grape to grape. Varieties with tight-clustered bunches are more susceptible. The fungus overwinters in debris on the ground and on the vine. Infection occurs throughout the growing season, mostly at bloom and again at veraison. Damage appears on leaves as brown, necrotic lesions. Botrytis rapidly spreads throughout the grape cluster. Botrytis bunch rot can destroy entire bunches, resulting in 25-50% yield loss in susceptible varieties. Tissue previously injured by hail, wind, birds, or insects is susceptible to Botrytis infection. Critical time for control is at bloom, at bunch closing and at veraison.
Nonchemical control of grape diseases:
Control of diseases depends on chemical and no-chemical means. Site selection can affect disease pressure. Locating vineyards in elevated sites as opposed to low areas having poor air drainage should be considered. Where possible, plant cultivars that are not highly susceptible to the more common diseases. Using a trellis and pruning practices that promote good sunlight penetration air circulation and spray penetration throughout the canopy will lessen disease pressure and improve pesticide performance. Maintaining a vineyard floor that will not impede air circulation and spray coverage is critical to disease and insect control. Sanitation is an essential disease control practice. Removing mummified fruit and weak or dead wood from the canopy and the vineyard floor will lessen infection pressure.
Chemical control of grape diseases:
Protectant fungicides:
PHI-Pre-harvest interval REI-Restricted-entry interval
Lime-sulfur
Target disease: anthracnose
Rate and frequency: 1 application during dormancy at 10 gallons per acre
Captan (Captan 50WP)
Target diseases: black rot, downy mildew, Phomopsis cane and leaf spot
Acres treated: 100%
Rate and frequency: 2 lb/acre at 10-14 day intervals as needed
PHI: 0 days
REI: 4 days
Comments: Often used later in season when PHI prevents use of mancozeb.
Mancozeb (Dithane 80WP)
Target diseases: black rot, downy mildew, Phomopsis cane and leaf spot
Acres treated: 100%
Rate and frequency: 3 to 4 lb/acre applied at 7-10 day intervals as needed
PHI: 66 days (limits use to early season applications)
REI: 24 hours
Comments: Mancozeb provides good control of most diseases except powdery mildew. Applied with a sterol inhibitor when also preventing powdery mildew.
Carbamate (Ferbam 76WG)
Target diseases: black rot, downy mildew
Acres treated: 15%
Rate and frequency: 2 lb/acre at 10-14 day intervals as needed
PHI: 7 days
REI: 24 hours
Comments: Maximum of three applications. Applied instead of captan or mancozeb.
Ziram (Ziram 76DF)
Target diseases: black rot, Phomopsis cane and leaf spot, downy mildew
Acres treated: 10%
Rate and frequency: 3 lbs./acre, apply at bud break, 3 to 5 inch shoot length, 8 to 10 inch shoot length, prebloom
PHI: 21 days
REI: 48 hours
Systemic fungicides:
PHI-Pre-harvest interval
REI-Restricted-entry interval
Sterol inhibitors:
Myclobutanil (Nova40WP)
Target diseases: black rot, powdery mildew
Acres treated: 75%1
Rate and frequency: 3-5 oz/acre at 7-14 day intervals
PHI: 14 days
REI: 24 hours
Comments: Potential for development of resistant strains of powdery mildew fungus limit use to maximum of 24 oz/acre/season.
Fenarimol (Rubigan 1EC)
Target diseases: black rot, powdery mildew
Acres treated: 20%
Rate and frequency: 6 fl oz/acre applied at 7-14 day intervals
PHI: 30 days
REI: 12 hours
Comments: Resistant strains of powdery mildew fungus limits use to maximum of 19 oz/acre/season.
Other systemic fungicides:
Azoxystrobin (Abound 2F)
Target diseases: black rot, downy mildew, powdery mildew, Phomopsis cane and leaf spot
Acres treated: 20%
Rate and frequency: 11 fl oz/acre at 10-14 day intervals applied in an alternating block spray program
PHI: 14 days
REI: 12 hours
Comments: Only fungicide that controls all four major diseases. Maximum of 6 applications/season. To prevent disease resistance, cannot be applied as two consecutive applications.
Kresoxim-methyl (Sovran 50WG)
Target diseases: black rot, Phomopsis cane and leaf spot, downy mildew
Acres treated: 5%
Rate and frequency: 3.2 - 4.8 oz. per acre, apply at bud break, shoot length 3 - 5 inches, shoot length 8 - 10 inches, prebloom, petal fall
PHI: 14 days
REI: 12 hours
Comments: Maximum of 4 applications a year, do not make over 3 consecutive applications before rotating to a fungicide having a different mode of action
Iprodione (Rovral 50WP)
Target disease: Botrytis bunch rot
Acres treated: less than 30% of total acres
Rate and frequency: 1.5-2 lb/acre applied 4 times
PHI: 7 days
REI: 12 hours
Weeds
Weeds compete with vines for moisture and nutrients. They can be alternate hosts for pests that can damage the vines and/or the crop. They also can reduce air flow throughout the vineyard resulting in increased potential for spring frost damage and diseases. The presence of weeds can make management of the vineyard more difficult.
Vineyard weed control starts a year or more prior to planting. At this time, noxious weeds can be eliminated from the site using cultural or chemical methods that would be difficult to impossible to utilize following planting. If herbicides are used, it is important to select products which would not leave a persistent residue that could damage young vines.
Weeds and grasses compete more successfully than young grapevines for moisture and nutrients. Shading of the vines by weeds may also be a problem. Their control includes mechanical methods since the number of herbicides labeled for young vines are limited.
Several herbicides are labeled for bearing vineyards. Care must be taken in their application to avoid drift onto grape leaves and fruit. Label directions concerning the age of vines and the rate and timing of application must be followed.
Most herbicide programs involve the use pf postemergence materials to control vegetation already growing and preemergence herbicides to control newly germinating weeds. A tank mix involves combining two or more herbicides in the same application. Often a postemergent herbicide and one or more preemergent herbicides may be applied at the same time. Advantages of a tank mix include control of a broader range of weed and grass species and the ability to achieve control at lower rates of each material. In most vineyards, annual grasses, broadleaf weeds and perennial weeds may all be problems.
Nonchemical weed control:
Mechanical weed control through the use of grape hoes or other methods of shallow cultivation are not widely used. They are more expensive than chemical weed control and are more apt to damage vines.
Mulches have been used in some vineyards. They do suppress weed growth and moderate both temperature and moisture levels in the soil. Mulches can harbor pests or provide areas for pests to exist where they are much more difficult to control. The expense of establishing and maintaining a much cover is more than the cost of chemical weed control.
Chemical control of weeds:
Approximately 90 percent of commercial vineyards in Tennessee are treated with herbicides for weed and grass control.
PHI-Pre-harvest interval
REI-Restricted-entry interval
Nonbearing vines:
Nonbearing vines are typically less than 3 years old and not yet producing at their full potential.
Postemergence control:
Glyphosate (Roundup)
Target weeds: most grasses and broadleaves
Application: 1-5 qt/acre in 10-40 gal water/acre
Applied as preemergence broadcast application, directed spray, or wiper application to growing weeds.
PHI: 14 days
REI: 12 hours
Comments: Avoid contact with vines or severe damage will occur.
Paraquat (Gramoxone Extra)
Target weeds: most grasses and broadleaves
Application: 2-3 pt/acre in 30-100 gal water/acre
Requires wetting agent. Sprayed directly on emerged weeds.
REI: 12 hours
Comments: Restricted-use pesticide. Avoid contact with young shoots, foliage, and fruit.
Glufosinate (Rely)
Target weeds: barnyard grass, foxtail, jimsonweed, sheperdspurse, smartweed
Application: 1 lb formula at 3-6 qt in a minimum of 20 gal of water/acre sprayed directly on emerged weeds
REI: 12 hours
Comments: Maximum application of 18 qt/acre/year.
Sulfosate (Touchdown)
Target weeds: grasses and broadleaves-jimsonweed, mustard, annual morningglory, ragweed, smartweed, velvetleaf
Application: 5.33 pt (maximum) in 10-30 gal water/acre/year. Requires a surfactant or wetting agent. Applied as spot treatment or as a wiper application.
REI: 12 hours
Comments: Do not use within 12 months of first harvest.
Fluazifop (Fusilade)
Target weeds: grasses
Application: 1-1.5 qt/acre plus crop oil concentrate at 1 qt or spreader at 1 pt in 25 gal water/acre
Applied to actively growing grass.
REI: 12 hours
Comments: Do not apply within 12 months of first harvest. Crop oils can severely burn young vines.
Clethodim (Prism)
Target weeds: grasses
Application: 13-34 fl oz/acre plus crop oil
May be used as spot treatment.
REI: 12 hours
Comments: Do not use within 12 months of first harvest. Do not apply more than 68 fl oz /acre/year. Crop oils can severely burn young vines.
Sethoxydim (Poast)
Target weeds: grasses
Application: 1.5-2.5 pt plus 2 pt crop oil in 10-20 gal water/acre Applied as directed spray when grass is actively growing.
REI: 12 hours
Comments: Maximum application of 2.5 pt/application or 5 pt/season. Crop oils can severely burn young vines.
Preemergence control:
Isoxaben (Gallery)
Target weeds: broadleaves-dandelion, lambsquarter, mustard, night-shade, ragweed, smartweed, velvetleaf
Application: 0.6-1.33 lb/acre in 10 gal of water applied late summer/early fall or spring prior to weed germination
REI: 12 hours
Comments: Do not apply within 12 months of first harvest.
Isoxaben and oryzalin (Snapshot 80 DF) most used formula
Target weeds: broadspectrum of grass and broadleaf control
Application: 2.5-5 lb/acre
REI: 12 hours
Comments: Do not use within 12 months of first harvest.
Oryzalin (Surflan)
Target weeds: grasses and broadleaves-lambsquarter, mustards, pigweed, purslane
Application: 2-6 qt/acre in 20-40 gal water/acre band-sprayed
REI: 12 hours
Napropamide (Devrinol)
Target weeds: grasses and broadleaves-mustards, purslane, pigweed
Application: 8 lb in 20 gal water/acre
REI: 12 hours
Comments: Do not allow spray to contact fruit or leaves.
Pendimethalin (Prowl)
Target weeds: grasses and broadleaves-lambsquarter, pigweed, purslane
Application: 2-4 qt in 20 gal water
REI: 12 hours
Comments: Apply only to dormant, nonbearing vines.
Dichlobenil (Casoron or Norosac)
Target weeds: grasses and broadleaves-jimsonweed, chickweed, lambsquarter, pigweed, ragweed, smartweed, velvetleaf
Application: 100-150 lb/acre soil surface applied Nov.-Feb.
REI: 12 hours
Comments: Can be applied 4 weeks after transplanting.
Bearing vines:
Preemergence herbicides:
Simazine (Princep)
Target weeds: grasses and broadleaves-jimsonweed, annual morninggglory, mustards, ragweed, smartweed, velvetleaf
Application: Sandy, light soils: 2.5 lb/acre; dark, heavy soils: 6 lb/acre in a minimum of 20 gal of water
Band-sprayed under trellis before weed germination. Often tank mixed with oryzalin or norflurazon.
REI: 12 hours
Comments: Vines must be established 3 years.
Norflurazon (Solicam)
Target weeds: grasses and many broadleaves-dandelion, fall
panicum, jimsonweed, mustards, ragweed, velvetleaf
Application: Sandy, light soils: 2.5 lb/acre; dark, heavy soils: 5 lb/acre in at least 20 gal of water
Band-sprayed below trellis before weed germination.
REI: 12 hours
Comments: Do not apply after bud break on sandy soils. Vines must be established 24 months.
Diuron (Karmex)
Target weeds: broad spectrum grass and broadleaf control
Application: Sandy, light soils: 2 lb/acre; dark, heavy soils: 4 lb/acre in 25-40 gal water
Rotated with norflurazon as weed populations change. Band-sprayed under trellis before weed germination.
REI: 12 hours
Comments: Vines must be established 3 years.
Postemergence control:
Glyphosate (Roundup)
Target weeds: most grasses and broadleaves
Application: 1-5 qt/acre in 10-40 gal water/acre applied as a broadcast application, directed spray or wiper application to growing weeds
PHI: 14 days
REI: 12 hours
Comments: Avoid contact with any part of the grapevine except mature bark.
Paraquat (Gramoxone Extra)
Target weeds: most grasses and broadleaves
Application: 2-3 pt/acre in 30-100 gal water/acre; use of a nonionic surfactant required.
Sprayed directly on emerged weeds. Applications repeated as needed.
REI: 12 hours
Comments: Restricted-use pesticide. Avoid contact with young shoots, foliage, fruit.
Glufosinate (Rely)
Target weeds: barnyard grass, foxtail, jimson weed, sheperdspurse, smartweed
Application: 3-6 qt/acre in a minimum of 20 gal water/acre sprayed directly on emerged weeds. Applications repeated as needed.
REI: 12 hours
Comments: Maximum application of 18 qt/acre in 12 months.
Contacts
Dr. David W. Lockwood
Dept. of Plant Sciences & Landscape Systems
Box 1071
University of Tennessee
Knoxville, TN 37901
Telephone: 865-974-7208
FAX: 865-974-8850
Email: dlockwood@utk.edu
Mr. Darrell Hensley
Dept. of Entomology & Plant Pathology
Box 1071
University of Tennessee
Knoxville, TN 37901
Telephone: 865-974-7138
FAX: 865-974-8868
References