Arsenal herbicide

What is Arsenal herbicide

Arsenal Herbicide is a non-selective herbicide manufactured by BASF that is used as a post-emergent treatment. It is designed to help control areas that are infected with woody vegetation and other invasive plant species.

Active Ingredient

The active ingredient in this herbicide is Imazapyr.

How does the herbicide work

This herbicide works by being absorbed into the plant through its leaves, stems, or roots and spreading throughout.

It blocks an enzyme called acetolactate synthase (ALS) or acetohydroxyacid synthase (AHAS) that plants need to make certain proteins for growth. Without these proteins, the plant stops growing, wilts, and eventually dies, including the roots, which prevents it from growing back.

Where to apply it

This herbicide’s versatility makes it effective for vegetation management in a wide range of environments, including aquatic and natural areas, as well as industrial and transportation infrastructure.

You can apply it in the following areas:

Aquatic sites: standing and flowing water, estuarine and marine areas, wetlands, riparian zones.
Forestry sites: for controlling undesirable vegetation in managed forest areas.
Pasture and rangeland: for controlling weeds and vegetation in grazing areas like pastures.
Nonagricultural lands: airports, highways, railroads, sewage disposal areas, farmyards, fence rows, non-irrigation ditch banks and barrier strips, wildlife management areas, recreation areas, campgrounds, trailheads, and trails.
Specific grass release: for the release and management of unimproved Bermudagrass and Bahiagrass.

When to apply the herbicide

Understanding the best time to apply the herbicide is key to achieving effective vegetation control. The timing depends on the growth stage of the target plants and the specific environment where it is used.

Spring (March to May): Apply early in the season when plants start to grow. This is a good time for certain weeds.
Summer (June to August): This is the best time to use the herbicide because most plants are actively growing, which makes the treatment more effective.
Autumn (September to November): Applying later in the season can be helpful, especially in forests, as it reduces the chance of harming good plants.

How to prepare it

Applying Arsenal herbicide effectively and safely involves several important steps.

Read the Label Thoroughly: Before using Arsenal® herbicide, carefully read the entire product label. This will provide essential information on proper usage, safety precautions, and specific application instructions.
Prepare the Necessary Equipment: Ensure you have all required equipment, including appropriate personal protective equipment (PPE) such as long-sleeved shirts, long pants, chemical-resistant gloves, and shoes plus socks. Additionally, have the proper application tools, like sprayers made of stainless steel, fiberglass, plastic, or plastic-lined steel, as recommended.
Mix the Herbicide Solution: In a clean mixing container, combine the specified amount of Arsenal® herbicide with water, following the dilution rates provided on the label. Add an appropriate adjuvant if required, and mix thoroughly to ensure a uniform solution.
Calibrate Application Equipment: Before application, calibrate your sprayer to ensure the correct amount of herbicide is applied uniformly over the target area. This step is crucial for effective weed control and to prevent over-application.
Apply the Herbicide: Apply the herbicide solution to the target vegetation, ensuring even coverage. Avoid spraying during windy conditions to minimize drift to non-target plants. Follow any specific application timing or conditions mentioned on the label.
Clean Equipment After Use: After application, thoroughly clean all equipment, including sprayers and mixing containers, by flushing them with water. Proper cleaning prevents corrosion and contamination of future applications.
Store Remaining Herbicide Safely: Store any remaining Arsenal® herbicide in its original container, tightly closed, in a cool, dry place away from food, feed, and domestic water supplies. Ensure the storage area is secure and out of reach of children and pets.

Always check the label carefully to ensure the herbicide is approved and legal for use in your area before application. For example, Arsenal is not permitted for use in California unless otherwise directed by supplemental labeling.

There are no restrictions on grazing after applying Arsenal. However, avoid cutting forage grass for hay until at least 7 days after application.

How long does it take to show results

The time to see results with Arsenal herbicide varies depending on the vegetation type and environmental conditions.

Herbaceous weeds usually show initial effects like wilting or discoloration within 4 to 6 weeks, while woody plants and brush may take several weeks to a few months, as the herbicide works through the plant systemically.

Weeds controlled

This herbicide is a highly effective solution for managing a wide range of tough and invasive weeds.

It is commonly used to control woody plants, broadleaf weeds, and grass species that compete with desirable vegetation.

Also, this herbicide is especially effective against perennial and annual weeds, as well as invasive species commonly found in forestry, utility rights-of-way, and aquatic environments.

Aquatic Weeds Controlled

Table 1. Floating Weeds
Common Name	Scientific Name	Use Rates and Application Directions
Floating heart^*	Nymphodes spp.	2 to 4 pints/A (0.5 to 1.0% solution) applied in 100 GPA water mix. Ensure 100% coverage of actively growing emergent foliage.
Frogbit^*	Limnobium spongia	1 to 2 pints/A (0.5% solution) applied in 100 GPA water mix. Ensure 100% coverage of actively growing emergent foliage.
Spatterdock^*	Nuphar luteum	Apply a tank mix of: 2 to 4 pints/A Arsenal + 4 to 6 pints/A glyphosate (0.5% Arsenal + 1.5% glyphosate) in 100 GPA water for best control. Ensure 100% coverage of actively growing emergent foliage.
Water hyacinth^*	Eichhornia crassipes	1 to 2 pints/A (0.5% solution) applied in 100 GPA water to actively growing foliage.
Water lettuce^*	Pistia stratiotes	1 to 2 pints/A (0.5% solution) applied in 100 GPA water mix. Ensure 100% coverage of actively growing emergent foliage.

^*Use not permitted in California unless otherwise directed by supplemental labeling.

Table 2. Emerged Weeds
Common Name	Scientific Name	Use Rates and Application Directions
Alligatorweed^*	Alternanthera philoxeroides	1 to 4 pints/A (0.5% solution) applied in 100 GPA water mix. Ensure 100% coverage of actively growing emergent foliage.
Arrowhead, duck-potato^*	Sagittaria spp.	1 to 2 pints/A (0.5% solution) applied in 100 GPA water mix. Ensure 100% coverage of actively growing emergent foliage.
Bacopa, lemon^*	Bacopa spp.	1 to 2 pints/A (0.5% solution) applied in 100 GPA water mix. Ensure 100% coverage of actively growing emergent foliage.
Parrot feather^*	Myriophyllum aquaticum	Foliage must be above water for sufficient Arsenal uptake. Apply 2 to 4 pints/A Arsenal to actively growing emergent foliage.
Pennywort^*	Hydrocotyle spp.	1 to 2 pints/A (0.5% solution) applied in 100 GPA water mix. Ensure 100% coverage of actively growing emergent foliage.
Pickerelweed^*	Pontederia cordata	2 to 3 pints/A (1% solution) applied in 100 GPA water mix. Ensure 100% coverage of actively growing emergent foliage.
Taro, wild / Coco yam / Dasheen / Elephant’s ear^*	Colocasia esculentum	4 to 6 pints/A (1.5% solution) applied in 100 GPA with a high-quality sticker adjuvant. Ensure good coverage of actively growing emergent foliage.
Water chestnut^*	Trappa natans	4 to 6 pints/A (1.5% solution) applied in 100 GPA with a high-quality sticker adjuvant. Ensure good coverage of actively growing emergent foliage.
Water lily^*	Nymphaea odorata	2 to 3 pints/A (1% solution) applied in 100 GPA water mix. Ensure 100% coverage of actively growing emergent foliage.
Water primrose^*	Ludwigia uruguayensis	4 to 6 pints/A (1.5% solution). Ensure 100% coverage of actively growing emergent foliage.

^*Use not permitted in California unless otherwise directed by supplemental labeling.

Table 3. Terrestrial/Marginal Weeds
Common Name	Scientific Name	Use Rates and Application Directions
Aquatic nightshade / Soda apple^*	Solanum tampicense	2 pints/A applied to foliage.
Bamboo, Japanese^*	Phyllostachys spp.	3 to 4 pints/A applied to foliage when actively growing, before setting seedhead. More foliage improves herbicide uptake, leading to better root kill.
Beach, vitex	Vitex rotundifolia	5% solution + 1% MSO foliar spray or 17% solution stem injection (hack and squirt).
Brazilian pepper / Christmasberry	Schinus terebinthifolius	2 to 4 pints/A applied to foliage.
Cattail	Typha spp.	2 to 4 pints/A (1% solution) applied to actively growing green foliage after full leaf elongation. Lower rates are effective in the North; higher rates are needed in the South.
Chinese tallow tree	Sapium sebiferum	16 to 24 fl ozs/A applied to foliage.
Cogongrass	Imperata cylindrica	Burn foliage, till the area, then fall-spray 2 quarts/A Arsenal herbicide + MSO applied to new growth.
Cordgrass, prairie	Spartina spp.	4 to 6 pints/A applied to actively growing foliage.
Cutgrass^*	Zizaniopsis miliacea	4 to 6 pints/A applied to actively growing foliage.
Elephant grass / Napier grass^*	Pennisetum purpureum	3 pints/A applied to actively growing foliage.
Flowering rush^*	Butomus umbellatus L.	2 to 3 pints/A applied to actively growing foliage.
Giant reed / Wild cane	Arundo donax	4 to 6 pints/A applied in spring to actively growing foliage.
Golden bamboo^*	Phyllostachys aurea	3 to 4 pints/A applied to foliage when actively growing, before setting seedhead. More foliage improves herbicide uptake, leading to better root kill.
Junglerice	Echinochloa colonum	3 to 4 pints/A applied to actively growing foliage.
Knapweed	Centaurea spp.	Russian knapweed: 2 to 3 pints/A + 1 quart/A MSO, fall-applied after senescence begins.
Knotweed, Japanese	Polygonum cuspidatum, Fallopia japonica	3 to 4 pints/A applied postemergence to actively growing foliage.
Melaleuca / Paperbark tree	Melaleuca quinquenervia	Established stands: Apply 6 pints/A Arsenal herbicide + 6 pints/A glyphosate + spray adjuvant. Use 4 quarts/A MSO for best results. Ground foliar application: Uniformly apply to ensure 100% coverage. Broadcast foliar control: Apply aerially in at least 2 passes at 10 gallons/A cross-treatment. Spot treatment: Use a 25% Arsenal + 25% glyphosate + 1.25% MSO solution in water for frill or stump treatment.
Nutgrass / Kili’p’opu^*	Cyperus rotundus	2 pints/A Arsenal + 1 quart/A MSO applied early postemergence.
Nutsedge^*	Cyperus spp.	2 to 3 pints/A applied postemergence to foliage or incorporated preemergence. Non-incorporated preemergence applications will not control.
Phragmites / Common reed	Phragmites australis	4 to 6 pints/A applied to actively growing green foliage after full leaf elongation. Ensure 100% coverage. For old stands, mow or burn, then treat regrowth at 5 feet tall. Lower rates are effective in the North; higher rates are needed in the South.
Poison hemlock^*	Conium maculatum	2 pints/A Arsenal + 1 quart/A MSO applied preemergence to early postemergence to rosettes before flowering.
Purple loosestrife	Lythrum salicaria	1 pint/A applied to actively growing foliage.
Reed canarygrass	Phalaris arundinacea	3 to 4 pints/A applied to actively growing foliage.
Swamp rose	Rosa palustris	2 to 3 pints/A applied to actively growing foliage.
Russian olive	Elaeagnus angustifolia	2 to 4 pints/A (1% solution) applied to foliage.
Saltcedar / Tamarisk	Tamarix spp.	Aerial application: 2 quarts Arsenal + 0.25% v/v NIS applied to actively growing foliage during flowering. Spot treatment: Use 1% Arsenal + 0.25% NIS solution. Wait at least 2 years before disturbing treated saltcedar to ensure effective control.
Smartweed	Polygonum spp.	2 pints/A applied early postemergence.
Sumac	Rhus spp.	2 to 3 pints/A applied to foliage.
Swamp morningglory / Kangkong / Water spinach	Ipomoea aquatica	1 to 2 pints/A Arsenal + 1 quart/A MSO applied early postemergence.
Torpedo grass	Panicum repens	4 pints/A (1.0 to 1.5% solution). Ensure good coverage of actively growing foliage.
White top / Hoary cress^*	Cardaria draba	1 to 2 pints/A applied in spring to foliage during flowering.
Willow	Salix spp.	2 to 3 pints/A Arsenal applied to actively growing foliage. Ensure good coverage.

^*Use not permitted in California unless otherwise directed by supplemental labeling.

Terrestrial Weed Control

Table 4. Grass Weeds
Common Name	Scientific Name	Habit²
Apply 2 to 3 pts/A¹
Annual bluegrass	Poa annua	A
Broadleaf signalgrass	Brachiaria platyphylla	A
Canada bluegrass	Poa compressa	P
Downy brome	Bromus tectorum	A
Fescue	Festuca spp.	A/P
Foxtail	Setaria spp.	A
Italian ryegrass	Lolium multiflorum	A
Johnsongrass⁴	Sorghum halepense	P
Kentucky bluegrass	Poa pratensis	P
Napier grass⁵	Pennisetum purpureum	P
Orchardgrass	Dactylis glomerata	P
Paragrass	Brachiaria mutica	P
Quackgrass	Agropyron repens	P
Sandbur	Cenchrus spp.	A
Smooth brome	Bromus inermis	P
Vaseygrass	Paspalum urvillei	P
Wild oats	Avena fatua	A
Witchgrass	Panicum capillare	A
Apply 3 to 4 pts/A ¹
Barnyardgrass	Echinochloa crus-galli	A
Beardgrass	Andropogon spp.	P
Bluegrass, annual	Poa annua	A
Bulrush⁵	Scirpus validus	P
Cheat	Bromus secalinus	A
Cogongrass	Imperata cylindrica	P
Crabgrass	Digitaria spp.	A
Crowfootgrass	Dactyloctenium aegyptium	A
Fall panicum	Panicum dichotomiflorum	A
Goosegrass	Eleusine indica	A
Itchgrass	Rottboellia exaltata	A
Lovegrass⁴	Eragrostis spp.	P
Maidencane⁵	Panicum hemitomon	A
Panicum, browntop	Panicum fasciculatum	A
Panicum, Texas	Panicum texanum	A
Prairie threeawn	Aristida oligantha	P
Sandbur, field	Cenchrus incertus	A
Signalgrass	Brachiaria platyphylla	A
Wild barley	Hordeum spp.	A
Woolly cupgrass	Eriochloa villosa	A
Apply 4 to 6 pts/A¹
Arrowwood	Pluchea sericea	A
Canada thistle	Cirsium arvense	P
Giant ragweed	Ambrosia trifida	A
Gray rabbitbrush	Chrysothamnus nauseosus	P
Little mallow	Malva parviflora	B
Milkweed	Asclepias spp.	P
Primrose	Oenothera kunthiana	P
Silverleaf nightshade	Solanum elaeagnifolium	P
Sowthistle	Sonchus spp.	A
Texas thistle	Cirsium texanum	P

¹Use higher rate where heavy or well-established infestations occur.

²Growth Habit: A = Annual, B = Biennial, P = Perennial

³Use higher labeled rates.

⁴Best control with applications before formation of fall leaf color.

⁵Tank mix with glyphosate.

⁶Degree of control may be species dependent.

⁷For water oak (Quercus nigra), laurel oak (Q. laurifloria), willow oak (Q. phellos), and live oak (Q. virginiana), use higher labeled rates.

⁸Suppression only.

⁹Use not permitted in California unless otherwise directed by supplemental labeling.

Table 5. Brush Species
Common Name	Scientific Name	Habit²
Apply 2 to 4 pts/A¹
Brazilian peppertree	Schinus terebinthifolius	P
Chinese tallow tree / Popcorn tree	Sapium sebiferum	P
Russian olive	Elaeagnus angustifolia	P
Sumac	Rhus spp.	P
Willow	Salix spp.	P
Apply 4 to 6 pts/A ¹
Alder	Alnus spp.	P
American beech	Fagus grandifolia	P
Ash³	Fraxinus spp.	P
Aspen	Populus spp.	P
Autumn olive	Elaeagnus umbellata	P
Bald cypress	Taxodium distichum	P
Bigleaf maple	Acer macrophyllum	P
Birch³	Betula spp.	P
Black gum⁴	Nyssa sylvatica	P
Black oak	Quercus kelloggii	P
Boxelder	Acer negundo	P
Ceanothis	Ceanothis spp.	P
Cherry^{3, 4}	Prunus spp.	P
Chinaberry	Melia azedarach	P
Chinquapin	Castanopsis chrysophylla	P
Cottonwood	Populus trichocarpa, P. deltoides	P
Cypress	Taxodium spp.	P
Dogwood³	Cornus spp.	P
Elm⁵	Ulmus spp.	P
Eucalyptus	Eucalyptus spp.	P
Hawthorn	Crataegus spp.	P
Hickory³	Carya spp.	P
Huckleberry	Gaylussacia spp.	P
Lyonia spp. including: Fetterbush, Staggerbush	Lyonia lucida, Lyonia mariana	P
Madrone	Arbutus menziesii	P
Maple	Acer spp.	P
Melaleuca	Melaleuca quinquenervia	P
Mulberry^{3, 6}	Morus spp.	P
Oak⁷	Quercus spp.	P
Persimmon⁴	Diospyros virginiana	P
Poison oak	Rhus diversiloba	P
Poplar	Populus spp.	P
Privet	Ligustrum vulgare	P
Red alder	Alnus rubra	P
Red maple	Acer rubrum	P
Saltcedar	Tamarix pentandra	P
Sassafras	Sassafras albidum	P
Sourwood⁴	Oxydendrum arboreum	P
Sweetgum	Liquidambar styraciflua	P
Sycamore	Platanus occidentalis	P
Tanoak³	Lithocarpus densiflorus	P
Titi⁸	Cyrilla racemiflora	P
Tree of heaven	Ailanthus altissima	P
Vaccinium spp. including: Blueberry, Sparkleberry	Vaccinium spp., Vaccinium arboreum	P
Water willow⁹	Justicia americana	P
Yellow poplar³	Liriodendron tulipifera	P

¹Use higher rate where heavy or well-established infestations occur.

²Growth Habit: A = Annual, B = Biennial, P = Perennial

³Use higher labeled rates.

⁴Best control with applications before formation of fall leaf color.

⁵Tank mix with glyphosate.

⁶Degree of control may be species dependent.

⁷For water oak (Quercus nigra), laurel oak (Q. laurifloria), willow oak (Q. phellos), and live oak (Q. virginiana), use higher labeled rates.

⁸Suppression only.

⁹Use not permitted in California unless otherwise directed by supplemental labeling.

Application Rates

Forestry use

Apply the herbicide at the recommended rate per acre to control woody plants and herbaceous weeds effectively, supporting site preparation and potential burns.

Use higher rates and spray volumes for dense canopies or difficult species, and consider tank mixes for tolerant plants while following all label restrictions.

Table 6. Application Rates for forestry use
Common Name	Scientific Name	Rate (fl ozs/A)
Loblolly pine	Pinus taeda	48 to 80
Loblolly X pitch hybrid	–	48 to 80
Longleaf pine	Pinus palustris	48 to 80
Shortleaf pine	Pinus echinata	48 to 80
Virginia pine	Pinus virginiana	48 to 80
Slash pine	Pinus elliottii	40 to 64
Coastal redwood	Sequoia sempervirens	24 to 48
Douglas fir	Pseudotsuga menziesii	24 to 48
Western hemlock	Tsuga heterophylla	24 to 48
California red fir	Abies magnifica	24 to 40
California white fir	Abies concolor	24 to 40
Jack pine	Pinus banksiana	24 to 32
Lodgepole pine	Pinus contorta	24 to 32
Pitch pine	Pinus rigida	24 to 32
Ponderosa pine	Pinus ponderosa	24 to 32
Sugar pine	Pinus lambertiana	24 to 32
White pine	Pinus strobus	24 to 32
Black spruce	Picea mariana	24 to 32
Red spruce	Picea rubens	24 to 32
White spruce	Picea glauca	24 to 32

Herbaceous Weed Control

Arsenal can be applied as a broadcast, banded, or directed spray to control weeds around young conifers. Avoid application when conifers are stressed by drought, disease, or other factors.

A nonionic surfactant (up to 0.5%) can improve weed control but should not be used with slash pine, longleaf pine, or Douglas fir.

For handheld sprayers, mix 0.8 to 1.2 fl oz of Arsenal and 0.2 oz of surfactant per gallon of water, targeting weeds while minimizing contact with conifers. Arsenal can also be tank-mixed with sulfometuron to control more weeds, but this may slow the growth of some conifers.

Table 7. Application Rates for Herbaceous Weed Control
Common Name	Scientific Name	Rate (fl ozs/A)
Loblolly pine	Pinus taeda	12 to 20
Loblolly X pitch hybrid	–	12 to 20
Virginia pine	Pinus virginiana	12 to 20
Longleaf pine	Pinus palustris	8 to 12
Slash pine	Pinus elliottii	8 to 12
Douglas fir	Pseudotsuga menziesii	8 to 12

Conifer Release Treatment

The application rates provided below are exclusively for broadcast applications aimed at releasing the following conifer species from competition with hardwood vegetation.

Table 8. Application Rates for Conifers
Common Name	Scientific Name	Rate (fl ozs/A)
Loblolly pine³	Pinus taeda	24 to 40
Loblolly X pitch hybrid³	–	24 to 40
Virginia pine³	Pinus virginiana	24 to 40
Longleaf pine	Pinus palustris	24 to 32
Pitch pine	Pinus rigida	24 to 32
Shortleaf pine	Pinus echinata	24 to 32
Slash pine	Pinus elliottii	24 to 32
White pine¹	Pinus strobus	16 to 32
California red fir	Abies magnifica	16 to 24
California white fir	Abies concolor	16 to 24
Lodgepole pine²	Pinus contorta	12 to 24
Douglas fir²	Pseudotsuga menziesii	12 to 24
Jack pine²	Pinus banksiana	12 to 24
Black spruce²	Picea mariana	12 to 24
Red spruce²	Picea rubens	12 to 24
White spruce²	Picea glauca	12 to 24

¹ Do not apply to white pine stands younger than three years old. To minimize potential injury to white pine, release treatments should not be made before July 15.

² Applications should be performed after the formation of final conifer resting buds in the fall to prevent height growth inhibition.

³ Mid-rotation release: For broadcast applications under the pine canopy in established stands of loblolly pine, loblolly X pitch hybrid, and Virginia pine, use 32 fl ozs to 64 fl ozs per acre. For mid-rotation release of other conifer species, refer to the rates listed in the corresponding chart.

Nonagricultural Use – Brush Control

Keep in mind that tank mixes with 2,4-D or products containing 2,4-D may reduce the effectiveness of Arsenal herbicide.

Table 9. Tank Mixes and Application Rates for Low-volume Foliar Brush Control
Target Vegetation	Arsenal Rate (% by volume)	Tank Mix
Mixed hardwoods without elm, locust, or pine	1.0 to 1.5	Surfactant
Mixed hardwoods containing elm, locust, and pine	0.5 to 1.0	Accord® at 2% to 3% by volume plus surfactant
Mixed hardwoods with locust and pine but no elm	0.5 to 1.0	Krenite® at 2% to 5% by volume
Mixed hardwoods with locust and elm but no pine	0.5 to 1.0	Escort® at 2 ozs/A or 2.3 grams/gal

Table 10. Backpack and Handheld Spray Mixing Guide
% Solution	Product per Gallon of Mix (fl ozs)	Product per 4-Gallon Backpack (fl ozs)
0.25	0.3	1.3
0.5	0.6	2.6
1.0	1.3	5.1
2.0	2.6	10.2
3.0	3.8	15.4
5.0	6.4	25.6

Selective Control of Undesirable Weeds in Unimproved Bermudagrass and Bahiagrass

For Bermudagrass, apply it at 6 to 12 fl ozs per acre when dormant, or at 6 to 8 fl ozs per acre after full greenup, including a surfactant in the spray solution.

For additional control of annual grass and small-seeded broadleaf weeds, Pendulum® AquaCapTM herbicide can be added. To manage Johnsongrass, mix Arsenal (8 fl ozs per acre) with Roundup® (12 fl ozs per acre) and surfactant. Garlon® 3A herbicide (1 to 2 pints per acre) may be added for further broadleaf and vine control.

For Bahiagrass, apply this herbicide at 4 to 8 fl ozs per acre either when dormant or after up to 25% greenup, always including a surfactant in the spray solution for effective application.

Adjuvants and Additives

Yes, for this herbicide, you need to use adjuvants to increase its effectiveness.

Adjuvants improve how the herbicide spreads, sticks to plant surfaces, and is absorbed by the target vegetation, ensuring better results in controlling unwanted plants.

Below are the types of adjuvants and their specific uses.

Nonionic Surfactant (NIS)

Use a nonionic surfactant at a rate of 0.25% volume/volume (v/v) or higher.
Example: 0.25% v/v equals 1 quart of surfactant per 100 gallons of spray solution.
For the best results, choose a surfactant with a hydrophilic-to-lipophilic balance (HLB) between 12 and 17 and ensure the product contains at least 70% surfactant.
Do not use products containing alcohol, fatty acids, oil, ethylene glycol, or diethylene glycol as substitutes for a proper surfactant.

Methylated Seed Oil (MSO) or Vegetable-based Oil Concentrates

You can use MSO or vegetable-based seed oil concentrates instead of a surfactant.
Recommended rate: 1.5 to 2 pints per acre.
For spray volumes over 30 gallons per acre, mix MSO or vegetable-based seed oil concentrates at 1% of the total spray volume. Alternatively, use a nonionic surfactant as described above.
These oils are especially helpful when plants are under stress from dry conditions or high temperatures, as they enhance the herbicide’s uptake.

Silicone-based Surfactants

Silicone-based surfactants help spray droplets spread better on leaves by lowering surface tension.
Be cautious: some silicone-based products may dry too fast, which can limit herbicide absorption.

Invert Emulsions

Arsenal can also be applied using an invert emulsion (a water-in-oil mixture). This method reduces spray drift and runoff, ensuring more herbicide stays on the target plants.

The invert emulsion can be mixed in a single tank or inline during application. Refer to the invert emulsion product label for detailed instructions.

Additional Products

You can also add when using this herbicide antifoaming agents to reduce foam, as well as spray pattern indicators to help you track application coverage.

EPA Registration Number

The EPA Reg. No. of this herbicide is 241-346.