General Information


Use Orion Herbicide as a postemergence herbicide for the control of annual broadleaf weeds such as chickweed, wild buckwheat, mustards and cleavers (catchweed bedstraw) in wheat (including spring, winter and durum), barley, oats, rye and triticale not underseeded with legumes.

Orion Herbicide rapidly stops growth of susceptible weeds. However, typical symptoms (discoloration) of dying weeds may not be noticeable for 1 to 2 weeks after application, depending upon growing conditions and weed susceptibility. Degree of control and duration of effect are dependent upon weed sensitivity, weed size, crop competition, growing conditions at and following treatment, and spray coverage.

Use Precautions

When applying this product in tank-mix combination, follow all applicable use directions, precautions, and limitations on each manufacturer’s label.

Chemigation: Do not apply this product through any type of irrigation system. Do not apply Orion Herbicide directly to, or otherwise permit it to come into direct contact with, susceptible crops or desirable plants including alfalfa, edible beans, canola, flowers and ornamentals, lentils, lettuce, peas, potatoes, radishes, soybeans, sugar beets, sunflowers, tomatoes, or tobacco. Do not permit spray mists containing Orion Herbicide to drift onto such plants.
This product has potential to leach. Do not apply excessive irrigation.
Do not apply to crops underseeded with legumes.

Resistant Weed Management

Orion Herbicide contains the active ingredients florasulam which inhibits acetolactate synthase (ALS, Site of Action Group 2) and MCPA which causes abnormal cell growth (synthetic auxin, Site of Action Group 4). Some naturally-occurring weed populations have been identified as resistant to Group 2 and 4 herbicides. Selection of resistant biotypes, through repeated use of these herbicides or lower than labeled use rates in the same field, may result in weed control failures. A resistant biotype may be present where poor performance cannot be attributed to adverse environmental conditions or improper application methods. If resistance is suspected, contact your local Syngenta representative and/or agricultural advisor for assistance.

Principles of herbicide resistant weed management:

- Employ integrated weed management practices. Use multiple herbicide sites-of-action with overlapping weed spectrums in rotation, sequences, or mixtures.
- Use the full labeled herbicide rate and proper application timing for the hardest to control weed species present in the field.
- Scout fields after herbicide application to ensure control has been achieved. Avoid allowing weeds to reproduce by seed or to proliferate vegetatively.
- Monitor site and clean equipment between sites.
- Start with a clean field and control weeds early by using a burndown treatment or tillage in combination with a preemergence residual herbicide as appropriate.
- Use cultural practices such as cultivation and crop rotation, where appropriate.
- Use good agronomic principles that enhance crop competitiveness.

Avoiding Injurious Spray Drift

This product can affect broadleaf plants directly through foliage and indirectly by root uptake from treated soil. Do not apply Orion Herbicide directly to, or allow spray drift to come into contact with, broadleaf crops including, but not limited to, alfalfa, canola, beans, cotton, flowers, grapes, lettuce, lentils, mustard, peas, potatoes, radishes, soybeans, sugar beets, sunflowers, tobacco, tomatoes, vegetables, or other desirable broadleaf crops or ornamental plants or soil where sensitive crops will be planted the same season. (See Crop Rotation Intervals section.)

Make applications only when there is little or no hazard from spray drift. Very small quantities of spray, which may not be visible, may seriously injure crops, whether dormant or actively growing. When applying Orion Herbicide, use low pressure equipment capable of producing sprays of uniform droplet size with a minimum of a medium-quality spray. Under adverse weather conditions, fine spray droplets that do not settle rapidly onto target vegetation may be carried a considerable distance from the treatment area. A drift control or spray thickening agent may be used with this product to improve spray deposition and minimize the potential for spray drift. If used, follow all use recommendations and precautions on the product label.

Ground Applications: To minimize spray drift, apply Orion Herbicide in a total spray volume of 8 gallons or more per acre using spray equipment designed to produce a medium or coarse spray according to the ASABE S-572.1. Refer to the spray equipment manufacturer’s recommendations for detailed information on nozzle types, arrangement, spacing and operating height and pressure. Spot treatments should be applied only with a calibrated boom to prevent over application. Operate equipment at spray pressures no greater than is necessary to produce a uniform spray pattern. Operate the spray boom no higher than is necessary to produce a uniformly overlapping pattern between spray nozzles. Do not apply with hollow cone-type nozzles or other nozzles that produce a fine-quality spray.

Aerial Application: To minimize spray drift, apply Orion Herbicide in a total spray volume of 3 gallons or more per acre. Drift potential is lowest between wind speeds of 2 to 10 mph. However, many factors, including droplet size and equipment type, determine drift potential at any given speed. Application should be avoided below 2 mph due to variable wind direction and high potential for temperature inversion. Spray drift from aerial application can be minimized by applying a coarse spray at spray boom pressure no greater than 30 psi; by using straight-stream nozzles directed straight back; and by using a spray boom no longer than 3/4 the rotor or wing span of the aircraft. Spray pattern and droplet size distribution can be evaluated by applying sprays containing a water-soluble dye marker or appropriate drift control agents over a paper tape (adding machine tape).

Do not apply under conditions of a low level air temperature inversion. A temperature inversion is characterized by little or no wind and lower air temperature near the ground than at higher levels. The behavior of smoke generated by an aircraft-mounted device or continuous smoke column released at or near site of application will indicate the direction and velocity of air movement. A temperature inversion is indicated by layering of smoke at some level above the ground and little or no lateral movement. Mechanical flagging devices may be used.

Limitations, Restrictions, and Exceptions


Application Timing

Apply Orion Herbicide early postemergence to actively growing weeds. Extreme growing conditions such as drought or near freezing temperatures prior to, at, or following time of application may reduce weed control and increase the risk of crop injury at all stages of growth. Only weeds that have emerged at the time of application will be controlled. If foliage is wet at the time of application, control may be decreased. Applications of Orion Herbicide are rainfast within 4 hours after application.

Spray Coverage

Use sufficient spray volume to provide thorough coverage and a uniform spray pattern. Do not broadcast apply in less than 3 gallons of total spray volume per acre. For best results and to minimize spray drift, apply in a spray volume of 10 gallons or more per acre. As vegetative canopy and weed density increase, spray volume should be increased to obtain equivalent weed control. Use only nozzle types and spray equipment designed for herbicide application. To reduce spray drift, follow precautions under Avoiding Injurious Spray Drift.


Generally this product does not require the use of an adjuvant to achieve satisfactory weed control. An adjuvant may be added to optimize herbicidal activity when applications are made at lower carrier volumes; under conditions of cool temperature, low relative humidity or drought; or when a tank-mix partner recommends the use of an adjuvant.

When an adjuvant is to be used with this product, the use of an adjuvant that meets the standards of the Chemical Producers and Distributors Association (CPDA) adjuvant certification program is recommended.


- Livestock may be grazed on treated crops 7 days following application.
- Do not exceed 0.75 lb ae of MCPA or 0.0044 lb ai of florasulam per acre per year from all combined uses.


- Volunteer canola: Including all herbicide-tolerant canola varieties.
- Flixweed, Prickly Lettuce and Annual sunflower: Up to the 4-leaf stage.
- Hempnettle and Redroot Pigweed: Improved control can be achieved with the addition of 1 oz. ae per acre of MCPA ester (2.2 fl. oz. per acre of a 3.7 lb. ae per gallon of product).

Pre-Harvest Interval

60 days

Restricted Entry Interval

12 hours