Crop and Pest Management Guidelines

6.7 Specialty Use Herbicides

CASORON 4G

CASORON 4G (dichlobenil) - read the label

Signal word: CAUTION

Medical emergency: (866) 928-0789

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. Granules must be evenly dispersed for maximum efficacy, so calibration of equipment is critical. 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, but repeat applications over time may be required.

DEVRINOL DF-XT

DEVRINOL DF-XT (napropamide) - read the label

Signal word: CAUTION

Medical emergency: (866) 673-6671

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 "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.

SCYTHE

SCYTHE (pelargonic acid) - read the label

Signal word: WARNING

Medical emergency: (888) 478-0798

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

Rate: Use a 3-5% solution for small annual weed burndown. Use a 5-10% solution for larger weeds and burndown of mature perennial weeds. Registered as a sucker control agent as well as a postemergence herbicide. Injury to sprayed weeds is evident within several minutes. Weed control is optimal when weeds are thoroughly covered. To attain this, the recommended spray volume is 75-200 gal per acre sprayed.

Timing: May be applied whenever weeds are actively growing. Repeat applications are necessary for large weeds and perennials that continue to emerge from underground parts.

Comments: Avoid application to any desirable green tissue, as injury will result. Strong odor can linger for several hours or days. Observe applicator precautions carefully.

SNAPSHOT 2.5 TG

^ SNAPSHOT 2.5 TG (trifluralin + isoxaben) - read the label

Signal word: CAUTION

Medical emergency: (800) 992-5994

Selected uses: Preemergence control of annual grasses and broadleaf weeds and, at the high use rate, suppression of some perennial weeds (including field bindweed) in nonbearing vineyards only. ^SNAPSHOT IS NOT REGISTERED FOR USE IN NEW YORK STATE.

Rate: Apply 100-200 lbs per acre surface treated. For use only on nonbearing vines that will not bear fruit for at least one year. Repeat applications of 150 lbs per acre and higher should not be made within 60 days of a previous application.

Timing: Apply prior to weed germination or just after cultivation. The active ingredient, trifluralin, is quite volatile and uniform incorporation by rainfall or cultivation should occur within three days of application, otherwise annual grass control may be erratic. Do not apply within one year of harvesting fruit.

Comments: ^Snapshot is a pre-mix of trifluralin (Treflan) and isoxaben (^Gallery) used more commonly in ornamentals. Where volatility is a concern, or where uniform granular applications are not possible, tank-mix ^Gallery (where legal) with an effective grass herbicide such as oryzalin (Surflan), pendimethalin (Prowl), or Devrinol.

TREFLAN

TREFLAN, others (trifluralin) - read the label

Signal word: CAUTION

Medical emergency: See label

Selected uses: Applied and incorporated prior to planting new vineyards for preemergence control of annual grasses and broadleaf weeds.

Rate: Depends on the formulation used and on soil texture and organic matter- consult the label.

Timing: Apply and incorporate within 24 hours of application prior to planting.

Comments: Local experience with these products is extremely limited, as other options are more practical.

WEEDZSTOP, BIO-WEED

WEEDZSTOP, BIO-WEED, several others (corn gluten meal) - read the label

Signal word: N/A

Medical emergency: N/A

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

Rate: Apply 20 lb per 1,000 sq ft (870 lb per acre surface applied). Can only be applied as a granular material.

Timing: Apply in the spring and the fall.

Comments: An organic product derived from cornmeal production. Contains about 10% soluble nitrogen, so at recommended use rate supplies about 87 lbs. actual nitrogen per acre surface treated. Although herbicidal activity has been observed in some greenhouse studies, little if any weed control efficacy has been observed in trials on turf conducted in New York. For those interested in trying it, a small evaluation trial is advised before large-scale applications are made.

6.6 Herbicides for Nonbearing Vineyards

7 Sprayer Technology