General Information

General Information

Guardsman Max herbicide is a selective preemergence herbicide for controlling most annual grasses, many annual broadleaf weeds and sedges in field corn, popcorn, seed corn, sweet corn, and grain sorghum (refer to Table 1. Weeds Controlled).

Weeds Controlled

Some weed species have triazine-resistant biotypes that will not be controlled adequately by this product. If resistant biotypes are suspected, use an alternate program or use nontriazine products such as Clarity herbicide or Prowl herbicide in combination or sequentially with Guardsman Max.

Mode of Action

Guardsman Max contains two active ingredients: dimethenamid-P, as an inhibitor of cell division, Group 15; and atrazine, an inhibitor of photosynthesis at photo system II Site A, Group 5. Guardsman Max typically controls weeds before or soon after they emerge from the soil.

Herbicide Resistance

Naturally occurring biotypes of certain pests with resistance to the atrazine component in Guardsman Max are known to exist. Selection of resistant biotypes, through repeated use of atrazine or related triazine herbicides (same mode of action), may result in reduced levels of control. If poor performance cannot be attributed to adverse weather conditions or improper application methods, a resistant biotype may be present. In such a case, additional treatments with this herbicide or related products are not recommended. Consult your local extension specialist or agricultural advisor for assistance in managing resistant weed biotypes.

Application Instructions

Apply Guardsman Max preplant surface, preplant incorporated, preemergence, or early postemergence to corn or sorghum. Guardsman Max will provide most effective weed control when applied (by ground or aerial equipment) and subsequently incorporated into soil by rainfall, sprinkler irrigation, or mechanical tillage prior to weed seedling emergence from soil. Apply Guardsman Max with either water or fluid fertilizer as the spray carrier, or impregnated onto and applied with dry bulk fertilizer. Sprayable fluid fertilizer as a carrier is not recommended for use after crop emergence unless the typical fertilizer burn symptoms on the crop are acceptable. Refer to Additives section for more information.

Application Rate

Use rates for Guardsman Max when used alone, in tank mix, or in sequential applications are given in Table 2 (refer to General Tank Mixing Information and Crop-specific Information sections for more details). Use rates of this product vary by soil texture and organic matter. Soil texture groupings used in the label are coarse (sand, loamy sand, sandy loam), medium (silt, silt loam, loam, sandy clay loam), and fine (sandy clay, silty clay, silty clay loam, clay loam, and clay).

When use rates are expressed in ranges, use the lower rates for more coarsely textured soils lower in organic matter; use the higher rates for more finely textured soils that are higher in organic matter. Reduced rates may be used where partial control or reduced length of soil residual control is required (refer to Table 2 in the label).

Application Timing

Preplant Surface Applications. For use in minimum tillage or no-tillage production systems, apply Guardsman Max alone or in tank mixes up to 45 days before planting. When making early preplant applications (15 to 45 days prior to planting), use the highest rate specified for the specific soil texture. Early preplant applications are not for use on coarse-textured soils or in areas where average annual rainfall (or rainfall + irrigation) typically exceeds 40 inches. Early preplant applications may be applied as part of a split application program where the second application is made after planting (use 2/3 of Guardsman Max rate early followed by 1/3 of rate after planting). Use a split application when the initial application is made more than 30 days prior to planting. Tank mixes with postemergence herbicides such as Clarity herbicide, glyphosate, Gramoxone Inteon herbicide, or Touchdown herbicide must be used when weeds are more than 1.5 inches tall at the time of application.

Preplant Incorporated Applications. Apply Guardsman Max and incorporate into the upper (1 to 2 inches) soil surface up to 2 weeks before planting. Use a harrow, rolling cultivator, finishing disk, or other implement capable of giving uniform shallow incorporation. Avoid deeper incorporation or reduced weed control may result.

Preemergence Surface Applications. Broadcast treatment uniformly to the soil surface after planting and before crop emergence. Rainfall, sprinkler irrigation, or shallow mechanical incorporation after application is required to move this product into the upper soil surface where weed seeds germinate. If adequate rainfall or irrigation does not occur and weed seedling emergence begins, a shallow cultivation or rotary hoeing will improve performance.

Early Postemergence Applications. Apply Guardsman Max early postemergence to corn or sorghum up to 12 inches tall. Apply Guardsman Max before weeds are greater than 1.5 inches tall, or in a tank mix with products that control emerged weeds.

Split Applications. Guardsman Max may be used in split application programs where applications are made as part of the methods described above. If applications are less than 2 weeks apart, the total Guardsman Max rate used must not exceed the maximum rate given for each specific soil type. If applications are 2 weeks or more apart, a total Guardsman Max use rate of up to 4.6 pints per acre per year may be used on any soil type.

Aerial Application Methods and Equipment

Water Volume. Use 2 or more gallons of water per acre. The actual minimum spray volume per acre is determined by the spray equipment used. Use adequate spray volume to provide accurate and uniform distribution of spray particles over the treated area and to avoid spray drift.

Ground Application (Banding)

When applying Guardsman Max herbicide by banding, determine the amount of herbicide and water volume needed.

Ground Application Methods and Equipment


Water Volume. Use 5 or more gallons of water per acre. The actual minimum spray volume per acre is determined by the spray equipment used. Adequate spray volume must be used to provide accurate and uniform distribution of spray particles over the treated area and to avoid drift of spray particles to nontarget areas.

Ground Application (Dry Bulk Fertilizer)

Guardsman Max may be impregnated or coated onto dry bulk granular fertilizer carriers for preplant surface, preplant incorporated, or preemergence applications. Impregnation of bulk fertilizer is restricted to commercial facilities. Onfarm bulk fertilizer impregnation is prohibited. No more than 500 tons of dry bulk fertilizer can be impregnated per day. No single facility may impregnate fertilizer with this product for more than 30 days per calendar year. The commercial facility impregnating the dry bulk fertilizer must inform, in writing, the user (applicator) of the dry bulk fertilizer that:

- Applicators must wear long-sleeved shirt, long pants, shoes and socks.

- The restricted-entry interval is 12 hours.

Impregnation or coating may be conducted by either the in-plant bulk system or the on-board system.

Guardsman Max herbicide may also be applied in herbicide tank mixes where the tank mix companion product is also registered for these application systems. Individuals or agents selling Guardsman Max in these application systems are responsible for following all state and local regulations regarding fertilizer and herbicide blending. The addition of a drying agent may be necessary if the fertilizer and herbicide blend is too wet for uniform application due to high humidity, high urea concentration, or low fertilizer use rate. Slowly add the drying agent to the blend until a flowable mixture is obtained. DO NOT use drying agents with on-board impregnation systems. Under some conditions, fertilizer impregnated with Guardsman Max may clog air tubes or deflector plates on pneumatic application systems. Mineral oil may be added to Guardsman Max before blending with fertilizer to reduce plugging. DO NOT use drying agents when mineral oil is used. To avoid separation of Guardsman Max and mineral oil mixes in cold temperatures, either keep mixture heated or agitated prior to blending with fertilizer. Mineral oil may be used at in plant blending stations or on-board injection systems.

Apply 200 to 750 pounds of fertilizer and herbicide blend per acre. Application must be made uniformly to the soil to prevent possible crop injury and offer satisfactory weed control. Impregnated fertilizer spread at half rate and overlapped to obtain a full rate will offer a more uniform distribution.

For granular fertilizer application, to protect small birds and mammals, soil incorporation of the granules is required. A shallow (1 to 2 inches) incorporation is desirable for improved weed control. Deeper incorporation may result in unsatisfactory weed control.

General Tank Mixing Information

Guardsman Max herbicide may be tank mixed with one or more herbicide products according to the crop specific tank mixing instructions in the label and respective product labels. Refer to Crop-specific Information to determine which tank mix products can be applied to specific crops.

Physical incompatibility, reduced weed control, or crop injury may result from mixing Guardsman Max with other pesticides (fungicides, herbicides, insecticides, or miticides), additives, or fertilizers. BASF does not recommend using tank mixes other than those listed on BASF labeling.

Local agricultural authorities may be a source of information when using other than BASF-recommended tank mixes.

Restrictions and Limitations

- Restricted Use Pesticide. This product is a restricted use herbicide due to groundwater and surface water concerns. Users must read and follow all precautionary statements and instructions for use to minimize potential for atrazine to reach groundwater and surface water.

- DO NOT apply through any type of irrigation system.

- DO NOT contaminate irrigation ditches or water used for domestic purposes.

- Maximum Seasonal Use Rate

DO NOT apply more than a total of 4.6 pints of Guardsman Max per acre per season.

Guardsman Max contains 3.3 pounds of the active ingredient atrazine per gallon (0.41 pound ai per pint).

When tank mixing or sequentially applying atrazine or products containing atrazine to corn or sorghum, the total pounds of atrazine applied (lbs ai/A) must not exceed the specific seasonal rate limits from preemergence, or postemergence, or preemergence + postemergence sequential applications, as follows:

- Prior to crop emergence

DO NOT exceed 1.6 pounds of atrazine ai per acre on highly erodible soils (as defined by the Natural Resource Conservation Service) with less than 30% plant residue cover. DO NOT exceed 2.0 pounds of atrazine ai per acre on other soils.

- After crop emergence

DO NOT exceed 2.0 pounds of atrazine ai per acre on any soil.

- Prior to and after crop emergence (sequential applications) or when tank mixing DO NOT exceed a total of 2.5 pounds of atrazine ai/acre on any soil per year.

- Preharvest Interval (PHI). Refer to Crop-specific

Information for crop-specific preharvest intervals and feeding and grazing restrictions.

- Stress. DO NOT apply to crops under stress, such as stress due to lack of moisture, hail damage, flooding, herbicide injury, mechanical injury, or widely fluctuating temperatures, because injury may result.

- Guardsman Max herbicide is not for sale, distribution, or use in Nassau or Suffolk counties in New York state.

Refer to the label for tank mix information.

Limitations, Restrictions, and Exceptions


(field, pop, seed, and sweet)

Apply Guardsman Max preplant surface, preplant incorporated, preemergence, or early postemergence to corn up to 12 inches tall. Corn in the label refers to field corn (grown for grain, silage, or seed), sweet corn (not including sweet corn grown for seed), and popcorn. Before applying Guardsman Max to seed corn, sweet corn, or popcorn, verify with your local seed company (supplier) the Guardsman Max selectivity on your inbred line or hybrid to help avoid potential injury to sensitive hybrids.

Refer to Application Instructions (Table 2.) to determine Guardsman Max use rates by soil type and use pattern.

Crop-specific Restrictions and Limitations

- Field corn forage may be grazed or fed to livestock 60 days or more after application of Guardsman Max.

- Sweet corn forage may be grazed or fed to livestock 45 days or more after application of Guardsman Max.

Sorghum (grain)

Apply Guardsman Max herbicide preplant, preplant incorporated, preemergence, or early postemergence to grain sorghum up to 12 inches tall.

All Guardsman Max applications must only be made to sorghum seed that has been properly treated by the seed company with an approved chloroacetamide herbicide safener or severe injury may occur.

For best performance, make preemergence surface applications within 5 days of the last preplant tillage. If grasses have emerged, Guardsman Max must be applied before they reach the 2-leaf stage or must be used in combination with an effective postemergence herbicide.

Under high soil moisture or cool conditions, Guardsman Max application may cause temporary stunting or leaf wrapping of sorghum. Sorghum will normally outgrow these symptoms in 10 to 14 days.

Refer to Application Instructions (Table 2.) to determine Guardsman Max use rates by soil type and use pattern.

Crop-specific Restrictions and Limitations

- DO NOT use Guardsman Max on sorghum planted in coarse-textured soil.

- Guardsman Max is not registered for use on sweet or forage sorghum.

- Sorghum forage may be grazed or fed to livestock 60 days or more after preemergence application of Guardsman Max.

- Sorghum forage may be grazed or fed to livestock 45 days or more after postemergence application of Guardsman Max.

- Grain and fodder may be harvested and fed 80 days or more after application of Guardsman Max.

Restricted Entry Interval

12 hours

Exception: If the product is soil injected or soil incorporated, the Worker Protection Standard, under certain circumstances, allows workers to enter the treated area if there will be no contact with anything that has been treated.