Trade name(s) Poast, Poast Plus, Prestige, Vantage

Manufacturer(s) BASF, Nufarm

Formulation(s) 1, 1.3, and 1.5 lb/gal emulsifiable concentrate.

Remarks A selective, postemergence herbicide to control most annual and perennial grasses. A crop oil concentrate enhances activity.

Water solubility 4,700 ppm at pH 7

Storage conditions Store between -4°F and 86°F in sealed containers.

Acute toxicity LD50 - 4,900 mg/kg

Action in plant Inhibits growing points of grasses.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor

Chemical family Cyclohexanedione

Koc Average is 100 mL/g (estimates) at pH 7


Rick Boydston
Revised March 2015

ASPARAGUS—Seedbeds and Early Establishment

See “Section N. Vegetable Crops: Site Preparation, Stale Seedbeds, and Selective Postemergence Applications” for additional options for weed control during asparagus establishment.

clethodim (several trade names)

Rate 0.07 to 0.12 lb ai/A

Ornamental Bulb, Rhizome, Corm, and Tuber Crops

Tim Miller
Revised March 2015

Crop rotations and cultural practices used to produce each crop influence the weed spectrum in cultivated or tilled fields. Annual weeds that grow and produce seed quickly, or perennials such as yellow nutsedge that are distributed by cultivation and plowing, often predominate in cultivated fields. Also, repeated use of the same or similar herbicides will select for resistant weed species, increase the number of tolerant weed biotypes, and change the population of soil microorganisms that degrade particular herbicides, resulting in shorter soil persistence.

Tomatoes, Peppers, and Eggplants

Ed Peachey
Revised March 2015

TOMATOES, PEPPERS, AND EGGPLANTS—General Weed Management Strategy

These three crops are members of the Solanaceae family, and can be either direct-seeded or planted as transplants. Although these crops are closely related, some herbicides are registered for use in one crop but not the others. For example, “Tomatoes only, must be established” means that particular herbicide is registered only for use on tomatoes, and only if the plants are beyond the 5- to 6-leaf stage. Always consult the label for rate and timing specifics.


Ed Peachey
Revised March 2015

RHUBARB—Winter Applications to Dormant Rhubarb

carfentrazone (Aim EC)

Rate Up to 0.031 lb ai/A (2 fl oz/A Aim EC)

Time After crop emergence, but only to row middles. Use hooded and shielded sprayers.

Peas (Green or English)

Tim Miller
Revised March 2015

PEAS (GREEN OR ENGLISH)—General Weed Management Strategy

Peas are drilled in closely spaced rows early in spring, which limits weed emergence and species diversity. Most growers apply herbicides to suppress or eliminate weed competition, or potential contamination of harvested product. Subsequent crop rotations during the same season limit herbicide choices to those exhibiting brief soil residuals.


Joel Felix
Revised March 2015

ONIONS—Site Preparation, Stale Seedbeds, and Selective Postemergence Applications

See “Site Preparation,” “Labeled Uses of Glyphosate in Vegetable Crops,” and “Registered Uses of Carfentrazone (Aim) Herbicide in Food Crops” in Section N. Vegetable Crops.


bensulide (Prefar 4-E)

Not for use in Willamette Valley of Oregon; garlic, dry bulb onions and shallots only (Idaho and Oregon only)

Leaf Crops

Ed Peachey
Revised March 2015

Crop groups 4A, 2, and 19

Leafy Greens Subgroup 4A:

Lettuce, endive (escarole), spinach, New Zealand spinach, Swiss chard, and arugula

Leaves of Root and Tuber Vegetables Group 2


Herbs Group 19

Cilantro (Coriander), dill, fennel, and parsley


Ed Peachey
Revised March 2015

GARLIC—General Weed Management Strategy

Garlic requires nearly perfect weed control because it emerges slowly and matures in 10 to 11 months, and its short vertical leaves never form a canopy. Growers, therefore, often control all weedy vegetation immediately before the crop emerges (often in wet weather), applying a selective soil-applied herbicide for winter weed control and adding treatments in spring, depending on specific weed infestations.

Cucurbit and Vine Crops

Ed Peachey
Revised March 2015

CUCURBIT AND VINE CROPS—Site Preparation, Stale Seedbeds, and Selective Postemergence Applications

See “Site Preparation”, “Labeled ‘L’ Uses for Glyphosate in Vegetable Crops” (table), and “Registered Uses of Carfentrazone (Aim) Herbicide in Food Crops” (table) at the beginning of “Section N. Vegetable Crops” in this handbook.

CUCURBIT AND VINE CROPS—Preplant Incorporated

bensulide (Prefar 4-E)

Sweet Corn (Fresh, Processing, and Seed)

Ed Peachey
Revised March 2015

CORN, SWEET—Preplant Incorporated and Preemergence Surface

acetochlor (Surpass or Cadence)

Rate 0.8 to 3 lb ai/A. Consult appropriate label for rates.

Time Apply preplant or preemergence.

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