Weeds are part of the vineyard ecosystem. Weed management decisions are based on balancing the positive and negative aspects of weed growth in the vineyard. Weeds can compete for water and nutrients, reducing vine growth; contaminate mechanically harvested fruit; provide alternate hosts for vineyard pests; and interfere with vineyard operations. Weed growth can also alter the microclimate around vines, leading to higher disease pressure and increasing the risk of spring frost. However, managing weed or cover crop growth in row middles can be a powerful tool for managing overly vigorous vines, minimizing erosion, and improving equipment access in wet seasons.

This portion of the guide primarily addresses chemical methods to control weeds in vineyards. We have attempted to include all herbicides labeled for use in grapes even though some are not commonly used in eastern United States vineyards. Recommended herbicides are listed in the sections, “recommended preemergence herbicides,” “recommended postemergence herbicides,” and “recommended herbicides for nonbearing vineyards.” Herbicides that are registered for vineyard use and are not generally recommended, but that may have applicability under specific circumstances, are listed in the section, “specialty use herbicides.”

Cultivation is sometimes used as a weed management tool in vineyards. Low vine size restricts productivity of own-rooted Vitis labruscana varieties such as ‘Concord’ that generally have shallow root systems. Effective herbicide use has been shown to increase vine size and subsequent yields as compared with under-the-row cultivation, but this may be less of a concern when deep-rooted rootstocks are used, when vines are overly vigorous, or when maximum yields are not desired.

Cultivation and organic mulches can also be used as tools for row middle management. Excessive cultivation can lead to undesirable consequences such as soil erosion, reduced soil organic matter, and breakdown in soil structure resulting in compaction and reduced permeability. Recently cultivated soil can restrict equipment mobility needed for critical vineyard operations such as timely pesticide applications and mechanical harvest. If cultivation is used for row middle management it is suggested that negative effects be limited by not cultivating more often than necessary to suppress weed growth, to shallow (1-2") depths only, and with the goal of reducing, rather than completely eliminating, weed or cover crop growth. Fall planting of ryegrass or other cover crops can be used in conjunction with cultivation to provide winter cover. Organic mulches are most effective where soil moisture and fertility are low and where low vine size restricts vineyard productivity.

6.1 Resources

Several resources are available to aid in determining and addressing vineyard weed management goals. The concepts and tools for weed management are covered in the Cornell vineyard weed management fact sheets, listed below and at the back of this guide. They are available at http://www.nysipm.cornell.edu/publications/grapeman/ index.html (table of contents for Grape IPM in the Northeast), through Cornell Cooperative Extension offices, or directly through the Bulletin Room at the New York State Agricultural Experiment Station, Geneva, NY.

The fact sheets in this series are:

· Choosing a weed management program, which discusses goals and management options, including cultivation, mowing, mulching, and the use of chemical weed control agents (herbicides);

· Chemical control of vineyard weeds, which discusses weed types, herbicide types, and factors to consider in using herbicides effectively;

· Pre-emergence herbicides, which discusses all the available residual herbicide options, including their behavior in soil, persistence, and means of loss from the soil;

· Post-emergence herbicides, which discusses available contact and systemic herbicides and how they affect plants and soil; and

· Managing vineyard floors using no-tillage, which discusses the reasons for avoiding tillage and practical factors to consider in using no-tillage as a weed management tool.

Additionally, Weeds of the Northeast is an excellent resource covering weed identification and aspects of weed biology and ecology that relate to weed management. Weeds of the Northeast is available through Cornell University Press and the Lake Erie Regional Grape Program office in Fredonia.

6.2 Effective use of Herbicides

Most herbicides are degraded in the soil by microbes. Repeated use of the same herbicides, or those with similar chemistry, can lead to a buildup of tolerant weeds, development of resistant biotypes, and more rapid microbial decomposition that can reduce the length of time soil active herbicides are effective. Although herbicide options in vineyards are somewhat limited, weed management programs should not rely on the repeated use of the same herbicides.

Table 6.2.1. Acres of vineyard sprayed at different row and spray band widths to equal one acre of land surface sprayed.
Width of Spray Band	Distance between rows
Width of Spray Band	8 ft	9 ft	10 ft
30 inches	3.2	3.6	4.0
36 inches	2.7	3.0	3.3
42 inches	2.3	2.6	2.9
48 inches	2.0	2.3	2.5

Example 1: When a 36-inch (3 foot) undertrellis spray band is treated and vineyard rows are 9 feet apart, 3 acres of vineyard are equivalent to 1 sprayed acre.

3’ treated band ÷ 9’ row width = 0.33 x 3 acres of vineyard
= 1 acre surface sprayed.

In Example 1, a 60-acre vineyard block would require sufficient herbicide to treat 20 acres of land surface:

60-acre vineyard block ÷ 3 acres = 20 acres of land surface treated.

If you choose to apply Acme Weed Killer at a rate of 4 lb product per acre surface sprayed, this 60-acre vineyard block would require 80 lb of Acme Weed Killer.

4-lb product per acre surface sprayed x 20 acres of land surface treated
= 80 lb of Acme Weed Killer.

Example 2: When a 42-inch (3.5-foot) undertrellis spray band is treated and vineyard rows are 9 feet apart, then 2.6 acres of vineyard are equivalent to 1 sprayed acre.

3.5’ treated band ÷ 9’ row width = 0.39 x 2.6 acres of vineyard
= 1 acre surface sprayed.

In Example 2, a 60-acre vineyard block would require sufficient herbicide to treat 23 acres of land surface:

60-acre vineyard block ÷ 2.6 acres = 23 acres of land surface treated.

If you choose to apply Acme Weed Killer at a rate of 4 lb product per acre surface sprayed, this 60-acre vineyard block would require 92 lb of Acme Weed Killer.

4-lb product per acre surface sprayed x 23 acres of land surface treated
= 92 lb of Acme Weed Killer.

6.3 Recommended Preemergence Herbicides

CHATEAU SW (flumioxazin) - read the label

Signal word: CAUTION

Medical emergency: (800) 892-0099

Selected uses: Preemergence control of broadleaf weeds and annual grasses

Rate: 6-12 oz. per acre surface sprayed. Two applications per season are allowed, but do not make a sequential application within 30 days of the first application, nor within 60 days of harvest. A maximum rate of 6 oz. per application should be used on any soil that has a sand content over 80% if vines are less than 3 years of age. Refer to the “Recommended herbicides for nonbearing vineyards” section for additional comments for use on young vines.

Timing: Applications are allowed at any time except within 30 days of a previous application or within 60 days of harvest. Do not apply after grape bloom unless using hooded or shielded application equipment and the applicator can ensure spray drift will not contact fruit or foliage with the exception of undesirable suckers.

Comments: Chateau provides preemergence control of most annual broadleaf weeds and grasses. Chateau also provides some postemergence activity on many weeds and grapevine suckers, however, it should be tank mixed with a labeled postemergence herbicide for control of emerged weeds. Observe any restrictions associated with the postemergence herbicide (glyphosate, paraquat, †Rely or Aim). Quicker burn down activity may be observed from tank mixes with a postemergence herbicide than with the postemergence herbicide alone. Avoid direct or indirect spray contact to foliage and green bark, with the exception of undesirable suckers. In some situations a single application of 12 oz. Chateau provides season-long control of annual weeds in vineyards. In other situations including heavy soil type, heavy weed pressure, or high precipitation, a split application may be necessary to achieve season-long weed control. In our experience, two applications of 6 oz. Chateau plus a postemergence herbicide, applied in early May and around grape bloom, have provided good season-long weed control.

GOAL 2XL, OXIFLO 2EC (oxyfluorfen) - read the label

Signal word: WARNING

Medical emergency: (800) 992-5994, (800) 308-5391

Selected uses: Preemergence control of broadleaf weeds and early season control of annual grasses in established vineyards.

Rate: Apply 5–8 pt per acre surface sprayed.

Timing: Must be applied before bud swell, as later applications may result in significant vine injury. Do not apply to vines established less than 3 years unless vines are on a trellis at least 3 feet above the soil surface.

Comments: Oxyfluorfen primarily controls annual broadleaf weeds and is quite effective in controlling pigweed species. Some control of annual grasses may be achieved, but season-long control of grasses is not expected. For season-long control of annual grasses, use a tank mix with †Solicam, oryzalin, or diuron.

KARMEX DF, DIREX DF, DIREX 4L, others (diuron) - read the label

Signal word: CAUTION

Medical emergency: (888) 324-7598; (800)441-3637

Selected uses: Preemergence control of broadleaf weeds and annual grasses in established vineyards.

Rate: Apply 2–6 lb of 80 DF or 1.6–4.8 qt of 4L per acre surface sprayed. The label urges caution for use on soils low in clay or organic matter (1–2%) and, under those conditions, limits the rate to 2–3 lb 80 DF or 1.6–2.4 qt 4L. Use 3–6 lb 80 DF, or 2.4–4.8 qt 4L, on soils high in clay or organic matter.

Timing: Apply in the spring just prior to germination and growth of annual weeds. Use only in vineyards established at least 3 years.

Comments: Diuron controls a broad spectrum of annual weeds but may not provide season-long control of some annual grasses, such as foxtail species. Tank mixing with a longer residual grass herbicide such as †Solicam or Surflan may be necessary to obtain season-long control of annual grasses. Observations suggest that repeated use of diuron over many years results in shorter residual weed control, probably due to enhanced microbial decomposition. Use of other herbicides in a rotational program is suggested.

PRINCEP Caliber 90, PRINCEP 4L, OTHERS (simazine) - read the label

Signal word: CAUTION

Medical emergency: (800) 888-8372

Selected uses: Preemergence control of broadleaf weeds and early season control of annual grasses in established vineyards.

Rate: Apply 2.2–5.3 lb of 90 WDG, or 2–4.8 qt of 4L per acre surface sprayed. Use the lower rate on coarse-textured soils low in organic matter.

Timing: Apply between harvest and early spring. Do not use in vineyards established less than 3 years.

Comments: Princep controls a broad spectrum of annual broadleaf weeds, but season-long control of annual grasses is not usually achieved. At low soil pH, hydrolysis enhances degradation and residual activity is shortened. For season-long control of annual grasses, use a tank mix with †Solicam, Surflan, or Karmex. New York has a FIFRA 2(ee) recommendation allowing the use of Princep for preemergence control of plantains.

^PROWL H2O (pendimethalin) – read the label

Signal word: CAUTION

Medical emergency: (800) 832-HELP

Selected uses: Preemergence control of annual grasses and control or suppression of some annual broadleaf weeds in bearing and non-bearing vineyards; must be applied when vines are dormant. At the time this was written (December 2007), Prowl H2O had just recently received EPA approval for use on bearing vines. Prowl H20 may now be used in Pennsylvania on bearing vines, but registration for this use in New York is pending. Consult extension specialists for updates regarding registration status for use in bearing vineyards in New York. Note that other formulations of pendimethalin have been registered for use in non-bearing vineyards for several years, but use in bearing vineyards is restricted to the “Prowl H20” formulation.

Rate: Apply 2-4 qt. per acre surface sprayed. The label suggests the higher rates for longer-term weed control.

Timing: The label states that Prowl H20 must be applied when vines are dormant, as later applications may result in leaf distortions.

Comments: The active ingredient in Prowl H20 (pendimethalin) is chemically similar to oryzalin (both are dinitroanalines) and the spectrum of weeds they control is similar. Pendimethalin is very weak in controlling some broadleaf weeds including ragweed and mustard species. Tank mix with Princep, Karmex, Goal, †Solicam, or Chateau for broad-spectrum weed control.

Note: Prowl H20 is also registered for use during vineyard establishment. That use is discussed in the section “Recommended herbicides for nonbearing vineyards.”

Note: “^” indicates not labeled for use in New York State

†SOLICAM DF (norflurazon) - read the label

Signal word: CAUTION

Medical emergency: (800) 888-8372

Selected uses: Preemergence control of annual grasses, suppression of perennial grasses, and control or suppression of some annual broadleaf weeds in established vineyards. †Solicam is no longer registered for use in Nassau and Suffolk Counties in New York and is not for sale, use, or distribution in these locations.

Rate: Apply 1.25–5 lb per acre surface sprayed. Consult the label to determine the proper use rate, which is based on soil texture.

Timing: Apply in fall or early spring prior to weed germination. Several inches of rainfall are needed to move the herbicide into the soil. Vines must be established at least 2 years.

Comments: †Solicam provides excellent season-long control of annual grasses and several annual broadleaf species including velvetleaf, and will provide some suppression of yellow nutsedge, plantains, and perennial grasses. †Solicam is relatively weak in controlling common annual broadleaf weeds such as pigweed and smartweed species and common lambsquarters. Tank mixes with another preemergence herbicide such as Princep, Karmex, Goal, or Surflan are needed to attain season-long, broad-spectrum weed control. Note that †Solicam is not registered for use in Nassau and Suffolk counties in New York.

SURFLAN A.S., FARMSAVER.COM ORYZALIN 4 A.S. (oryzalin) - read the label

Signal word: CAUTION

Medical emergency: (800) 992-5994, (800) 424-9300, (800) 858-7378

Selected uses: Preemergence control of annual grasses and control or suppression of some annual broadleaf weeds in bearing and nonbearing vineyards.

Rate: Apply 2–6 qt per acre surface sprayed. Length of control depends on the rate applied.

Timing: Apply in the fall or spring prior to weed germination. Do not apply to newly planted vines until soil has settled.

Note: Oryzalin is also registered for use during vineyard establishment. That use is discussed in the section “Recommended herbicides for nonbearing vineyards.”

6.4 Recommended Postemergence Herbicides

AIM (carfentrazone-ethyl) – read the label

Signal word: CAUTION

Medical emergency: (800) 331-3148

Selected uses: Postemergence control of certain susceptible broadleaf weeds and burn down of grapevine suckers

Rate: For broadleaf weed control, apply up to 1.98 fl. ozs. per acre surface sprayed. Lower rates can be used to control small seedling weeds at the 2 to 3-leaf stage; higher rates are needed for larger weeds up to the 6-leaf stage. Applications to weeds beyond the six-leaf stage may result in only partial control. For burn down of grapevine suckers, apply at the maximum use rate (1.98 fl. ozs.) per acre surface sprayed. Add non-ionic surfactant (NIS) at 2 pints per 100 gallons or crop oil concentrate (COC) at one gallon per 100 gallons.

Timing: Aim may be applied at any time during the season, but do not allow spray mist to contact desirable fruit, foliage, or green bark. Suckers and other undesirable growth must be treated when the tissue is young (not mature or hardened off). Multiple applications per season are allowed, but do not apply more than 8.5 fl. ozs. per season. Do not make applications less than 14 days apart or within 3 days of harvest.

Comments: Aim was newly registered for grape in 2005 so vineyard use experience is limited. Refer to the label for a list of susceptible broadleaf weeds. In limited evaluation, Aim was more effective than *Gramoxone for burn down of grapevine suckers. Suckers turned brown within 24 hours of Aim application but regrowth and new sucker growth was apparent within two weeks of the initial application. Multiple applications are necessary to obtain season-long sucker control. Aim may be tank-mixed with other preemergence or postemergence herbicides. In our limited 2005 trials, a tank-mix of Aim plus *Gramoxone provided increased burn down of suckers, and more broad-spectrum weed control, than either herbicide applied alone.

*GRAMOXONE MAX, *GRAMOXONE INTEON (paraquat) – RESTRICTED USE PESTICIDE –

read the label

Signal word: DANGER

Medical emergency: (800) 888-8372

Selected uses: Postemergence burn down of all weeds in new or established vineyards and burn down of grapevine suckers up to 8 inches long.

Rate: *Gramoxone Inteon contains 2 lb. of the active ingredient, paraquat, per gallon. Apply 2.5-4 pt per acre surface sprayed.*Gramoxone Max is a more concentrated formulation that contains 3 lb of the active ingredient, paraquat, per gallon. Apply 1.75-2.7 pt *Gramoxone Max per acre surface sprayed. Always add a nonionic surfactant (NIS) or crop oil concentrate (COC). Add NIS at 1 pt per 100 gal (75% or more surface-active agent), or NIS at 2 pt per 100 gal (50–74% surface-active agent), or COC at 1 gal per 100 gal. The label permits applications in as low as 10 gal per treated acre, but spray volume should be increased as necessary to obtain complete coverage of target weeds or suckers without runoff from the target foliage.

Timing: *Gramoxone should be applied to emerged weeds when they are small. Weeds 1–6 inches tall are easiest to control. Contacted plant foliage wilts and desiccates within hours of application, with complete necrosis in 1–3 days. For burndown of grapevine suckers, treat when sucker growth is no more than 8 inches long. For mature woody weeds, perennial weeds, late-germinating weeds, and green suckers, retreatment or spot -treatment may be necessary. Late season applications to weeds should be made to avoid contact with desirable foliage. Contact of spray or mist with fruit is expressly prohibited on the label and is not a legal use of the product. *Gramoxone applications are most effective under cool, cloudy conditions when drying time is slow and uptake into target foliage is optimal.

Comments: *Gramoxone is a dangerous poison and can be fatal if swallowed or inhaled. It is harmful if absorbed through the skin and can cause substantial eye injury. Follow all label precautions when mixing and applying. In vineyards where chemical suckering is undesirable, avoid contact with suckers by making a directed application under appropriate environmental conditions or use shielded equipment. Tank mixes with appropriate preemergence herbicides are recommended for broad-spectrum control and residual activity.

POAST (sethoxydim) - read the label

Signal word: WARNING

Medical emergency: (800) 832-HELP

Selected uses: Postemergence control of young annual grasses and suppression or control of perennial grasses in bearing vineyards and nonbearing vineyards, but not within 50 days of harvest.

Rate: Apply 1–2.0 pt per acre surface sprayed, depending on the grass species present. Add recommended adjuvant or crop oil concentrate at recommended rates.

Timing: Apply to actively growing grasses at recommended rates before they exceed the recommended growth stages on the label. (Examples: apply 1 pt per acre when foxtail species are less than 8 inches tall; apply 1.5 pt per acre when quackgrass is less than 8 inches tall.) Repeat treatments may be necessary for full season control.

Comments: Spray to obtain thorough coverage of grass foliage, but not to runoff. Observe the 50-day preharvest interval.

†RELY (glufosinate) - read the label

Signal word: WARNING

Medical emergency: (800) 334-7577

Selected uses: Postemergence burndown of all weeds in new or established vineyards and burndown of grapevine suckers up to 12 inches long. †RELY IS NOT REGISTERED FOR USE IN NASSAU AND SUFFOLK COUNTIES IN NEW YORK.

Rate: Apply 3–6 qt per acre surface sprayed. Consult the label for the appropriate rate, which is based on height and species of weeds present. Additional surfactant is not needed.

Timing: Best results are obtained when applications are made to actively growing weeds. Warm temperatures, high humidity, and bright sunlight improve the performance of †Rely. Contacted foliage wilts within days of application, with complete necrosis in 1–2 weeks. Repeat applications may be necessary. For grapevine sucker control, two applications 4 weeks apart at 4 qt/A are recommended when suckers are less than 12 inches long.

Comments: †Rely is primarily a contact herbicide (similar in activity to paraquat) with limited systemic activity. Damage to grapevine tissue is generally localized to contacted areas (burning of suckers or shoot tips in the herbicide application zone). †Rely controls most annual weeds and some biennials and perennials, including burdock, curly dock and wild onion species. Avoid direct spray or drift to desirable vegetation. Avoid contact with green bark on young vines as injury may occur. In vineyards where chemical suckering is undesirable, avoid contact with suckers by making a directed application under appropriate environmental conditions or use shielded equipment. Tank mixes with appropriate preemergence herbicides are recommended for broad-spectrum control and residual activity.

ROUNDUP (various formulations), TOUCHDOWN (various formulations) others (glyphosate) - read the label

Signal word: CAUTION

Medical emergency: (314) 694-4000, (800) 327-8633

Selected uses: Postemergence systemic control of annual and perennial weeds in bearing and nonbearing vineyards where contact with green grapevine foliage can be avoided.

Rate: Glyphosate products are available in several formulations of varying concentration. Some products list the amount of active ingredient (ai) on the label, others list the acid equivalent (ae).

Use the following table as a guide to determine the appropriate amount of product to use to apply typical rates of the active ingredient glyphosate:

Product	Active Ingredient (ai) Per gallon product	Amount of product to use at typical use rates (fl oz/A)
Product	Active Ingredient (ai) Per gallon product	1 lb ai	1.5 lb ai	2 lb ai
Original Roundup, Roundup Ultra, Touchdown IQ	4 lb (ai)	32	48	64
^Roundup UltraMax	5 lb (ai)	26	39	52
Roundup WeatherMax	5.5 lb (ai)	22	33	44
Touchdown Total	4.17 lb (ae)	24	35	48
Touchdown High Tech	5 lb (ae)	20	30	40

Consult the individual product labels to determine the appropriate rate for use in specific situations. Many perennial weeds require a higher rate of glyphosate than shown on the above table for effective control. Glyphosate is most effective when applied at lower gallonage and higher concentration. Typical vineyard applications are made at about 10 gal/A sprayed. Note maximum allowable gallonage restrictions on product labels. Effective rates are dependent upon many factors including weed species present, growth stage, and environmental factors. Many small annual weeds can be controlled with applications of 0.5-1.0 lb. ai/A glyphosate while many perennial weeds require higher rates for control. Consult product labels for specific rate recommendations and the addition of surfactant. (The Roundup Ultra label states not to add a surfactant while the Touchdown IQ label states up to 1 qt per 100 gal nonionic surfactant of at least 75% active ingredient may be added.) The addition of ammonium sulfate (AMS) may increase the effectiveness of glyphosate products, particularly under hard water conditions, drought conditions, or when tank mixing with residual herbicides. Add dry AMS at 8.5-17 lb per 100 gal or use equivalent rates of liquid AMS.

Timing: Glyphosate applications should not be made when green shoots, canes, or foliage are in the spray zone. Plant growth is inhibited soon after application, followed by foliar chlorosis within several days (depending on temperature and other factors) and complete necrosis within 1–3 weeks. Glyphosate is absorbed by mature foliage and translocated to other plant parts. To avoid injury, applications should be made before the end of grape bloom, or with shielded sprayers or wiper equipment, but not within 14 days of harvest. Optimal application timing information can be found on product labels. Most annual weeds can be controlled any time they are emerged and actively growing. More effective control of perennial weeds is achieved at the flowering or seed head stage of growth. Control of perennial weeds is most effective when glyphosate is applied to mature leaves capable of translocating the herbicide throughout the plant. For control of woody perennials and other hard-to-control perennial weeds, make applications to actively growing weeds as late as legally possible, prior to leaf senescence on the target weeds. Perennial grasses and other actively growing perennial weeds can be controlled with fall applications, which can be made after 100 percent natural grape leaf fall after harvest.

Comments: Glyphosate can be used as a substitute for cultivation in the row middles as described in the Cornell fact sheet, “Managing Vineyard Floors Using No-tillage.” Tank mixes with appropriate preemergence herbicides are recommended for broad-spectrum control and residual activity.

6.5 Recommended Herbicides for Nonbearing Vineyards

AIM (carfentrazone-ethyl) – read the label

Signal word: CAUTION

Medical emergency: (800) 331-3148

Selected uses: Postemergence control of certain susceptible broadleaf weeds.

Rate and timing: Refer to information under “Recommended postemergence herbicides.”

Comments: Avoid any contact with foliage and green bark on young vines.

CHATEAU SW (flumioxazin) - read the label

Signal word: CAUTION

Medical emergency: (800) 892-0099

Selected uses: Preemergence control of broadleaf weeds and annual grasses

Rate: 6-12 oz. per acre surface sprayed. A maximum rate of 6 oz. per application should be used on any soil that has a sand content over 80% if vines are less than 3 years of age. Two applications per season are allowed, but do not make a sequential application within 30 days of the first application.

Timing: Applications are allowed at any time except within 30 days of a previous application.

Comments: The Chateau label states “do not apply to grapes established less than two years unless they are trellised at least 3 feet from the soil surface or are protected from spray contact by non-porous wraps, grow tubes or waxed containers.” Research conducted on gravelly soil at the Vineyard Lab in Fredonia has shown substantial vine stunting from Chateau applications on newly-planted, own-rooted ‘Concord’ vines, even when protected with non-porous grow tubes. Observe label restrictions regarding rates, soil types, and use of protective grow tubes when using Chateau on non-bearing vines.

DEVRINOL 50-DF (napropamide) - read the label

Signal word: CAUTION

Medical emergency: (800) 858-7378

Selected uses: Preemergence control of annual grasses and some annual broadleaf weeds in bearing and nonbearing vineyards.

Rate: Apply 8 lb per acre surface sprayed.

Timing: Apply in fall or early spring before weeds emerge. Do not apply to frozen ground. Best results are achieved when incorporation into the soil by rainfall occurs soon after application.

Comments: Devrinol degrades upon exposure to sunlight (called “photodegradation”). The label states that incorporation by rainfall should occur within 24 hours of application. Although Devrinol is not chemically related to the dinitroanaline herbicides (oryzalin and pendimethalin), it controls a similar spectrum of weeds. Ragweed is a particularly common escape weed in new plantings, and weed competition can hamper vine establishment. In states other than New York, tank mixing with ^Gallery should provide more broad-spectrum weed control. Another option in new vineyards is to cultivate around the vines once or twice to control ragweed, and then apply Devrinol as a directed spray to freshly cultivated ground. The Devrinol label says to “avoid contact with fruit or foliage,” although local experience indicates little or no injury occurs from foliar contact. Note that late spring or summer applications of Devrinol are most sensitive to photodegradation, so applications should be made when sufficient precipitation for incorporation into the soil is expected soon after application.

FUSILADE DX (fluazifop-P-butyl) - read the label

Signal word: CAUTION

Medical emergency: (800) 888-8372

Selected uses: Selective postemergence control of young annual grasses and suppression or control of perennial grasses in nonbearing vineyards only.

Rate: Apply 16–24 oz per acre surface sprayed. Add crop oil concentrate or nonionic surfactant at recommended rates.

Timing: Apply to actively growing grasses before they exceed the recommended growth stages indicated on the label. (Examples: when annual grasses are 2–8 inches tall and prior to heading; when quackgrass is 6–10 inches tall.) Repeat treatments may be necessary for full season control.

Comments: Spray to obtain thorough coverage of grass foliage, but not to runoff. Avoid contact of spray with grapevine foliage.

^GALLERY 75 DF (isoxaben) - read the label

Signal word: CAUTION

Medical emergency: (800) 992-5994

Selected uses: Preemergence control of broadleaf weeds in nonbearing vineyards only. ^GALLERY IS NOT REGISTERED FOR USE IN NEW YORK STATE.

Rate: Apply 0.66–1.33 lb per acre surface sprayed.

Timing: Apply prior to weed germination or immediately after cultivation in nonbearing vineyards only. Do not apply until soil has settled and no cracks are present, or plant injury may occur. Do not apply within one year of harvesting fruit. ^GALLERY IS NOT REGISTERED IN NEW YORK STATE AND CANNOT LEGALLY BE APPLIED THERE.

Comments: ^Gallery primarily controls broadleaf weeds. Tank mix with an effective grass herbicide such as oryzalin, Devrinol, or pendimethalin for broad-spectrum weed control during vineyard establishment.

*GRAMOXONE MAX, *GRAMOXONE INTEON (paraquat)—RESTRICTED-USE PESTICIDE - read the label

Signal word: DANGER

Medical emergency: (800) 888-8372

Selected uses: Postemergence burndown of all weeds in new or established vineyards and burndown of grapevine suckers up to 8 inches long.

Rate and timing: Refer to the discussion under “Recommended postemergence herbicides.”

Comments: *Paraquat is a contact herbicide that desiccates all green plant tissue. Avoid contact of spray or mist with young vines—apply as a directed spray, use shielded equipment, or protect young vines using non-permeable grow tubes.

POAST (sethoxydim) - read the label

Signal word: WARNING

Medical emergency: (800) 900-4044

Selected uses: Postemergence control of young annual grasses and suppression or control of perennial grasses in bearing vineyards and nonbearing vineyards, but not within 50 days of harvest.

Rate and timing: Refer to the discussion under “Recommended postemergence herbicides.”

Comments: Spray to obtain thorough coverage of grass foliage, but not to runoff.

PROWL H2O, PROWL 3.3 EC, PENDIMAX 3.3 EC (pendimethalin) – read the label

Signal word: CAUTION

Medical emergency: (800) 832-HELP, (800) 992-5994

Selected uses: Preemergence control of annual grasses and control or suppression of some annual broadleaf weeds in nonbearing (first or second year) vineyards only; must be applied when vines are dormant.

Rate: Apply 2-4 qt. per acre surface sprayed of Prowl H2O, or 2.4-4.8 qt per acre surface sprayed of 3.3 EC formulations. The labels suggest the higher rates for longer-term weed control.

Timing: The labels state that pendimethalin must be applied when vines are dormant, as later applications may result in leaf distortion. Research indicates leaf injury is limited to exposed foliage and subsequent growth of vines is not affected. Only applications to newly-planted and second-leaf vines are permitted. The labels state that applications should not be made to newly transplanted vines until the soil is settled and no cracks are present.

Comments: Pendimethalin is chemically similar to oryzalin (both are dinitroanalines) and the spectrum of weeds they control is similar. Ragweed is a particularly common escape weed in new plantings, and weed competition can reduce vine growth during establishment. In states other than New York, tank mixing with ^Gallery should provide more broad-spectrum weed control. Only dormant applications are permitted. If a combination of early-season cultivation followed by herbicide application during the growing season is intended during vineyard establishment, better choices include oryzalin or Devrinol. Prowl H2O is a newer water-based formulation of pendimethalin with less odor than the older products. Vineyard evaluations conducted in 2003 indicated similar efficacy with the two formulations. Applications of Prowl H2O to grapevine foliage were less injurious than applications of 3.3 EC formulation, but label restrictions (i.e. dormant applications only) still apply.

†RELY (glufosinate) - read the label

Signal word: WARNING

Medical emergency: (800) 334-7577

Rate and timing: See discussion under “Recommended post-emergence herbicides.”

Comments: Avoid contact with foliage and green bark on young vines as injury may occur. Apply as a directed spray, use shielded equipment, or protect young vines using non-permeable grow tubes.

*SELECT 2 EC (clethodim) – read the label

Signal word: WARNING

Medical emergency: (800) 892-0099

Selected uses: Postemergence control of young annual grasses and suppression of control of perennial grasses in nonbearing vineyards only. Note the restriction for use on Long Island, NY.

Rate: Apply 6-8 fl. oz. per acre surface sprayed, depending on the grass species present. Add a non-ionic surfactant containing at least 80% active ingredient at the rate of 1 pt. per 50 gals.

Comments: Application on Long Island, New York, is restricted to no more than 16 fl. oz. per acre per season. For all other areas, do not apply more than 32 fl. oz. per season. Do not apply more than 8 fl. oz. per application. Note that higher rates can be applied on certain other crops under heavy grass pressure or at maximum weed heights but the higher rates are not labeled for use in grape.

SURFLAN A.S., FARMSAVER.COM ORYZALIN 4 A.S. (oryzalin) - read the label

Signal word: CAUTION

Medical emergency: (800) 992-5994, (800) 424-9300, (800) 858-7378

Selected uses: Preemergence control of annual grasses and control or suppression of some annual broadleaf weeds in bearing and nonbearing vineyards.

Rate: Apply 2–6 qt per acre surface sprayed. Length of control depends on the rate applied.

Timing: Apply in the fall or spring prior to weed germination. Do not apply to newly planted vines until soil has settled.

Comments: Oryzalin may be applied safely to coarse-textured, low organic matter soils where other residual herbicide options are limited. It is not recommended for use on soils with an organic matter content greater than 5 percent, and weed residues on the soil surface can reduce its effectiveness. Oryzalin is very weak in controlling some broadleaf weeds including ragweed and mustard species. Ragweed is a particularly common escape weed in new plantings, and weed competition can hamper vine establishment. In states other than New York, tank mixing with ^Gallery should provide more broad-spectrum weed control. Another option in new vineyards is to cultivate around the vines once or twice to control ragweed and other weed seedlings, then apply oryzalin as a directed spray to recently cultivated soil. The oryzalin labels do not prohibit contact with new growth on vines and experience indicates this is a safe use of the product.

ROUNDUP (various formulations), TOUCHDOWN (various formulations), others (glyphosate) - read the label

Signal word: CAUTION

Medical emergency: (314) 694-4000, (800) 888-8372

Selected uses: Postemergence systemic control of annual and perennial weeds in bearing and nonbearing vineyards where contact with grapevine foliage can be avoided.

Rates and timing: See discussion under “Recommended post-emergence herbicides.”

Comments: Perennial weeds should be eliminated during site preparation prior to vineyard establishment. Applications of glyphosate to nonbearing vines should be made only when contact with green grapevine tissue can be avoided - when vines are dormant, when shielded equipment is used, or when vines are protected with non-permeable grow tubes.

6.6 Specialty Use Herbicides

CASORON 4G (dichlobenil) - read the label

Signal word: CAUTION

Medical emergency: (800) 292-5898

Selected uses: Preemergence control of annual broadleaf weeds, early season control of annual grasses, and suppression or control of some perennial weeds.

Rate: Apply 100–150 lb per acre surface treated for annual weed control, or 150 lb per acre for control of established perennial weeds.

Timing: For annual weed control, apply in the spring prior to germination. For perennial weed control, apply between November 15 and February 15. For new plantings, do not apply before 4 weeks after planting.

Comments: Casoron is unusual among preemergence herbicides in that it controls many perennial as well as annual weeds. It is relatively expensive at recommended use rates and requires specialized equipment for application, so it is rarely used in vineyards. Limited experience in New York suggests season-long control of annual grasses might not be achieved. Spot treatment of Casoron might be useful in areas with problematic perennial weeds.

DEVRINOL 50-DF (napropamide) - read the label

Signal word: CAUTION

Medical emergency: (800) 858-7378

Selected uses: Preemergence control of annual grasses and some annual broadleaf weeds in bearing and nonbearing vineyards.

Rate and timing: See the Devrinol section under “Recommended herbicides for nonbearing vineyards.”

Comments: Devrinol is recommended for use during vineyard establishment (with appropriate caveats) where herbicide options are limited; it is also labeled for use in bearing vineyards. Ragweed and other common annual broadleaf species are not controlled with Devrinol, and season-long control of annual grasses is not usually achieved, so Devrinol is not often used in established vineyards.

*KERB 50W (pronamide) - RESTRICTED-USE PESTICIDE -read the label

Signal word: CAUTION

Medical emergency: (800) 992-5994

Selected uses: Pre- and postemergence control of annual and perennial grasses in bearing and nonbearing vineyards established six months or more. Fall applications only.

Rate: Apply 2–8 lb per acre surface sprayed.

Timing: Apply in the fall after harvest but before the soil freezes.

Comments: *Kerb is somewhat unusual among soil-active herbicides used in vineyards; sensitive weeds absorb it through the roots and it is effective in controlling both annual and perennial grasses and some annual broadleaf weeds. The label states that use on soils with more than 4 percent organic matter may result in incomplete weed control. Degradation of the active ingredient occurs when soil temperatures reach 55°F, so season-long control of susceptible weeds is unlikely. Effective perennial grass control can also be achieved with systemic post emergence herbicides such as glyphosate, and several preemergence herbicides can provide season-long control of annual grasses.

SCYTHE (pelargonic acid)—read the label

Signal word: WARNING

Medical emergency: (800) 992-5994

Selected uses: Postemergence burndown of all weeds in bearing and nonbearing vineyards; repeat applications necessary for larger annual weeds and for perennials.

Rate: </

Pest Management Guidelines A Cornell Cooperative Extension Publication	New York and Pennsylvania Pest Management Guidelines for Grapes
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