General Information

Product Information

Arsenal is an aqueous solution to be mixed with water and a surfactant and applied as a spray solution to control undesirable vegetation growing within specified aquatic, pasture/rangeland, industrial noncropland sites, and railroad, utility, and highway rights-of-way, and fence rows. Aquatic sites consist of standing and flowing water, estuarine/marine, wetland, and riparian areas. Industrial noncropland sites include utility plant sites, petroleum tank farms, pumping installations, fence rows, storage areas, and nonirrigation ditchbanks. Arsenal may also be used for the establishment and maintenance of wildlife openings, for the release of unimproved Bermudagrass and Bahiagrass, for bareground weed control, and for use under certain paved surfaces.

Herbicidal Activity. Arsenal will control most annual and perennial grasses and broadleaf weeds in addition to many brush and vine species with some residual control of undesirable species that germinate above the waterline. Arsenal is readily absorbed through emergent leaves and stems and is translocated rapidly throughout the plant with accumulation in the meristematic regions. For maximum activity, weeds should be growing vigorously at the time of application, and the spray solution should include a surfactant (see Adjuvants section for specific recommendations). Treated plants stop growing soon after spray application.

Chlorosis appears first in the newest leaves, and necrosis spreads from this point. In perennials, the herbicide is translocated into and kills underground or submerged storage organs, which prevents regrowth. Chlorosis and tissue necrosis may not be apparent in some plant species until 2 or more weeks after application. Complete kill of plants may not occur for several weeks. Applications of Arsenal are rainfast 1 hour after treatment.

Application Methods. Arsenal may be selectively applied using low-volume directed application techniques or may be broadcast applied using ground equipment, watercraft, or aircraft (aerial applications to aquatic sites must be made by helicopter). In addition, Arsenal may also be applied using cut stump, cut stem, and frill or girdle treatment techniques within noncropland, pasture/rangeland, and aquatic sites (see Aerial Application and Ground Application sections for additional details).

Precautions for Avoiding Injury to Nontarget Plants

Untreated desirable plants can be affected by root uptake of Arsenal from treated soil. Injury or loss of desirable plants may result if Arsenal is applied on or near desirable plants, on areas where their roots extend, or in locations where the treated soil may be washed or moved into contact with their roots. When making applications along shorelines where desirable plants may be present, caution should be exercised to avoid spray contact with their foliage or spray application to the soil in which they are rooted. Shoreline plants that have roots which extend into the water in an area where Arsenal herbicide has been applied generally will not be adversely affected by uptake of the herbicide from the water.

If treated vegetation is to be removed from the application site, DO NOT use the vegetative matter as mulch or compost on or around desirable species.

Aerial Application

All precautions should be taken to minimize or eliminate spray drift. Both fixed-wing aircraft and helicopters can be used to apply Arsenal on noncropland sites, but only helicopters can be used for aquatic applications. DO NOT make applications by fixed-wing aircraft or helicopter unless appropriate buffer zones can be maintained to prevent spray drift out of the target area, or when treating open tracts of land, spray drift as a result of fixed-wing aircraft application can be tolerated. Aerial equipment designed to minimize spray drift, such as a helicopter equipped with a Microfoil boom, Thru-Valve boom, or raindrop nozzles, must be used and calibrated. Except when applying with a Microfoil boom, a drift control agent may be added at the recommended label rate. Side trimming is not recommended with Arsenal herbicide unless death of treated tree can be tolerated.

Uniformly apply the specified amount of Arsenal in 2 to 30 gallons of water per acre. A foam-reducing agent may be added at the recommended label rate, if needed. IMPORTANT: Thoroughly clean application equipment, including landing gear, immediately after use of this product. Prolonged exposure of this product to uncoated steel (except stainless steel) surfaces may result in corrosion and failure of the exposed part. The maintenance of an organic coating (paint) may prevent corrosion.

Ground Application


Low-volume Foliar Application

Use equipment calibrated to deliver 5 to 20 gallons of spray solution per acre. To prepare the spray solution, thoroughly mix in water 0.5% to 5% Arsenal plus surfactant (see the Adjuvants section of the label for specific recommendations). A foam-reducing agent may be applied at the recommended label rate, if needed. For control of difficult species (see Aquatic Weed Control and Terrestrial Weed Control for relative susceptibility of weed species), use the higher concentrations of herbicide and/or spray volumes, but DO NOT apply more than 6 pints of Arsenal per acre in aquatic and noncropland sites and 3 pints per acre in pasture/rangeland. Excessive wetting of foliage is not recommended. See Spray Solution Mixing Guide for Low-volume Foliar Application following for specified volumes of Arsenal and water.

For low-volume foliar application, select proper nozzles to avoid overapplication. Proper application is critical to ensure desirable results. Best results are achieved when the spray covers the crown and approximately 70 percent of the plant. The use of an even, flat-fan tip with a spray angle of 40 degrees or less will aid in proper deposition. Recommended tip sizes include 4004E or 1504E. For a straight-stream and cone pattern, adjustable cone nozzles, such as 5500 X3 or 5500 X4, may be used. Attaching a rollover valve onto a Spraying Systems Model 30 gunjet or other similar spray gun allows for the use of both flat-fan and cone tips on the same gun.

Moisten, but DO NOT drench target vegetation causing spray solution to run off.

Low-volume Foliar Application with Backpacks

For low-growing species, spray down on the crown, covering crown and penetrating approximately 70% of the plant. For target species 4 to 8 feet tall, swipe the sides of target vegetation by directing spray to at least 2 sides of the plant in smooth vertical motions from the crown to the bottom. Make sure to cover the crown whenever possible. For target species over 8 feet tall, lace sides of the target vegetation by directing spray to at least 2 sides of the target in smooth zigzag motions from crown to bottom.

Low-volume Foliar Application with Hydraulic Handgun Application Equipment

Use the same technique as described for Low-volume Foliar Application with Backpacks.

For broadcast application, simulate a gentle rain near the top of target vegetation allowing spray to contact the crown and penetrate the target foliage without falling to the understory. Herbicide spray solution that contacts the understory may result in severe injury or death of plants in the understory.

High-volume Foliar Application

For optimum performance when spraying medium-density to high-density vegetation, use equipment calibrated to deliver up to 100 gallons of spray solution per acre (GPA). Spray solutions exceeding 100 GPA may result in excessive spray runoff, causing increased ground cover injury and injury to desirable species.

To prepare the spray solution, thoroughly mix Arsenal in water and add a surfactant A foam-reducing agent may be added at the recommended label rate, if needed. For control of difficult species (see Aquatic Weed Control and Terrestrial Weed Control for relative susceptibility of weed species), use the higher concentrations of herbicide and/or spray volumes, but DO NOT apply more than 6 pints of Arsenal per acre in aquatic and noncropland sites and 3 pints per acre in pasture/rangeland.

Uniformly cover the foliage of the vegetation to be controlled, but DO NOT apply to runoff. Excessive wetting of foliage is not recommended.

Resistant Biotypes

Naturally occurring biotypes (a plant within a given species that has a slightly different but distinct genetic makeup from other plants of the same species) of some weeds listed on the label may not be effectively controlled. If naturally occurring resistant biotypes are present in an area, tank mix Arsenal or apply sequentially with an appropriate registered herbicide having a different mode of action to ensure control.

Limitations, Restrictions, and Exceptions

Control of Undesirable Weeds Under Paved


Arsenal can be used under asphalt, pond liners and other paved areas, ONLY in industrial sites or where the pavement has a suitable barrier along the perimeter that prevents encroachment of roots of desirable plants. Use Arsenal only where the area to be treated has been prepared according to good construction practices. If rhizomes, stolons, tubers or other vegetative plant parts are present in the site, remove them by scalping with a grader blade to a depth sufficient to ensure their complete removal.

IMPORTANT: Follow Arsenal applications with paving as soon as possible. DO NOT apply where Arsenal may contact the roots of desirable trees or other plants. Use caution when considering use under pavement on residential properties, such as driveways or parking lots, or for use in recreational areas, such as under bike or jogging paths, golf cart paths, or tennis courts, or where landscape plantings could be anticipated. Injury or death of desirable plants may result if this product is applied where roots are present or where roots may extend into the treated area. Roots of trees and shrubs may extend a considerable distance beyond the branch extremities (drip line). Apply to the soil surface only when final grade is established. DO NOT move soil following Arsenal application. Apply Arsenal in sufficient water (at least 100 gals per acre) to ensure thorough and uniform wetting of the soil surface, including the shoulder areas. Add Arsenal at 6 pints per acre (2.2 fluid ounces per 1000 square feet) to clean water in the spray tank during the filling operation. Agitate before spraying.

If the soil is not moist prior to treatment, incorporation of Arsenal is needed for herbicide activation. Incorporate Arsenal into the soil to a depth of 4 to 6 inches using a rototiller or disc. Rainfall or irrigation of 1 inch will also provide uniform incorporation. DO NOT allow treated soil to wash or move into untreated areas.

Restricted Entry Interval

48 hours