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GF-1966 is a soluble granular herbicide intended for dilution with water and for use on canola, sugar beets, rutabagas, summerfallow, flax (including low linolenic acid varieties), wheat (spring), barley (spring), oats, strawberry, seedling and established grasses grown for forage and seed production, noncrop farmland, balsam fir Christmas trees and highbush blueberry. It is readily absorbed by both foliage and roots and translocates both upwards and downwards in plants. The product controls Canada thistle, wild buckwheat, scentless chamomile, common groundsel and volunteer alfalfa. It suppresses growth of perennial sow-thistle through control of top growth.



Sensitive Plants
Do not apply GF-1966 directly to, or otherwise permit it to come into contact with sunflowers, legumes (such as peas, beans, lentils or alfalfa), fruit or vegetable crops, flowers or other desirable broadleaved plants. Take precautions to prevent spray mists containing it to drift onto them. Residues of GF-1966 can remain in the soil following the year of use, thereby affecting growth of sensitive crops.
Special precautions should be taken during application to non cropland areas such as roadsides, pipelines and railways where sensitive desirable vegetation may be present. Do not apply to or allow drift to come into contact with sensitive desirable vegetation such as vetch or clover which may be found on embankments.

Non-Target Sites
Avoid contamination of non-target land, water or irrigation ditches. Do not use GF-1966 in the following areas: standing or flowing water; the inner banks or bottoms of irrigation ditches; in areas where surface water can run off to adjacent croplands either planted or to be planted to sensitive crops.

Crop Rotation
Fields previously treated with GF-1966 can be seeded the following year to wheat, oats, barley, rye (not underseeded with legumes, clover or alfalfa), forage grasses, flax, canola, mustard or it can be summerfallowed.
Do not seed to crops other than those listed above in the calendar year following treatment.

Tank Mixtures
Do not mix or apply this product with any other additive, pesticide or fertilizer except as specifically recommended on this label.

Grazing and Harvesting for Feed
There are no restrictions on the grazing of crops or forages treated with GF-1966. If necessary, treated areas may be grazed immediately following application.

Manure and Straw
Residues of the herbicide occurring in the straw may be harmful to susceptible plants; therefore, do not use straw or crop residue from treated crops for composting or mulching susceptible broadleaved crops. If the straw or crop residue is used for animal bedding or feed, return the manure to fields to be planted to clopyralid tolerant crops such as wheat, barley, oats, rye, forage grasses, canola or flax. Do not grow susceptible crops such as peas, beans, lentils, potatoes, sunflowers or other sensitive crops on land which has been mulched with straw containing GF-1966 residues within the last 12 months.


Field sprayer application: DO NOT apply during periods of dead calm. Avoid application of this product when winds are gusty. DO NOT apply with spray droplets smaller than the American Society of Agricultural Engineers (ASAE) medium classification. Boom height must be 60 cm or less above the crop or ground.

To Reduce Spray Drift:

1. Use nozzles that deliver higher volumes and coarser droplets.
2. Use low pressures (200 to 275 kPa).
3. Use 100 to 200 L/ha of spray solution.
4. Spray when the wind velocity is 15 km/hr or less.

Equipment Clean-Up

Equipment used to apply GF-1966 should not be used to apply other pesticides to sensitive crops without thorough cleaning. Contact your GF-1966 dealer for a detailed equipment cleaning procedure.


Spray Preparation
To prepare the spray solution add about half the desired amount of water to the spray tank, then with mechanical or bypass agitation, add the recommended amount of GF-1966. Mix thoroughly in the tank.
Second, add the recommended tank-mix herbicide. Finally with continued agitation, add the rest of the water.

Spray Application Volume
Apply GF-1966 at 140 to 415 g/ha plus any other herbicide approved as a tank-mix at the recommended rate in sufficient water to ensure thorough coverage (100 to 200 L/ha of spray solution) by ground equipment only at pressures of 200 to 275 kPa. Treat when weeds are young and actively growing, when the Canada thistle is in the rosette to pre-bud stage and before the purple bud stage and volunteer alfalfa is 5-50 cm in height.

Weed Stages at Application
Applications of GF-1966 should be made when Canada thistle, perennial sow-thistle and scentless chamomile are in the rosette to pre-bud stage of growth. Best results are obtained when Canada thistle is actively growing and soil moisture is adequate for rapid growth. Under dry soil conditions and poor growing conditions, control of Canada thistle may be severely reduced. Applications of GF-1966 made after the Canada thistle flower has reached the purple bud stage will not provide satisfactory control.

Control of Canada Thistle
For in crop control of top growth of Canada thistle apply GF-1966 at the rate of 210 g/ha. This will suppress top growth of Canada thistle for 6 to 8 weeks. Some regrowth may occur by the end of the season but this will not interfere with the harvesting of the crop.
For season long control of top growth of Canada thistle apply GF-1966 at the rate of 280 g/ha. This rate will generally provide season long control of Canada thistle. Not all rhizomes will be killed and some regrowth may occur by the end of the growing season.
For season long control of top growth, with a reduction of Canada thistle population in the following year, apply GF-1966 at the rate of 415 g/ha. This rate will provide season long control of Canada thistle and suppression into the following season, resulting in a reduction of the total number of Canada thistle shoots in the treated area.

CANOLA (Western Canada Only)
For use on Polish and Argentine varieties, including canola. GF-1966 should be diluted with water and applied at the 2 to 6 leaf stage of the crop to effectively control Canada thistle, scentless chamomile, common groundsel, wild buckwheat, the top growth of perennial sow-thistle and volunteer alfalfa. For specific directions for control of Canada thistle only refer to the section entitled Control of Canada Thistle.

Tank-mix Combinations in Canola

FLAX, Including Low Linolenic Acid Varieties (Western Canada Only)
For use in flax, GF-1966 should be applied when the flax is 5 to 10 cm high and the weeds are actively growing. Use GF-1966 at 280 to 415 g/ha to control Canada thistle, common groundsel, scentless chamomile, wild buckwheat, perennial sow-thistle (top growth) and volunteer alfalfa.
The 415 g/ha rate will extend control of Canada thistle into the following year.

GF-1966 may be used on wheat (spring), barley (spring) and oats to control Canada thistle, common groundsel, perennial sow-thistle (top growth control), wild buckwheat, scentless chamomile and volunteer alfalfa. GF-1966 should be applied when the wheat, barley or oats are between the 3 leaf to flag leaf emergence stages of growth and weeds are actively growing. Since GF-1966 damages legumes such as clover and alfalfa, these should not be undersown into the cereals. See Grazing and Harvesting for Feed
Section of label for grazing/harvesting intervals for immature crops.

Rates of Use
GF-1966 may be used alone in cereals for Canada thistle control.
Use 210 g/ha of GF-1966 for the control of top growth of Canada thistle. This rate will suppress top growth of Canada thistle for 6 to 8 weeks. Some regrowth may occur by the end of the season but will not interfere with the harvesting of the crop.
Use 280 g/ha of GF-1966 for season long control of Canada thistle.

For Canada thistle control apply GF-1966 at 280 to 415 g/ha with ground equipment as a foliar spray either broadcast or in a band over the row. When applied in the band, the amount of GF-1966 should be reduced proportional to the band width. GF-1966 should be applied when sugarbeets are in the cotyledon to 8 leaf stage. For the most effective control of Canada thistle, apply GF-1966 as a broadcast treatment to the entire infested area. Do not apply within 90 days of harvest.


For control of common ragweed, apply GF-1966 with a boom sprayer at the rate of 280 g/ha in approximately 200 to 300 L/ha of water. Apply as a postemergent spray when ragweed plants are 5 to 10 cm tall. Application to larger ragweed plants will result in reduced weed control. Make only one application per season. Preharvest interval is 83 days.

Uses of the following spray methods or equipment DO NOT require a buffer zone: hand-held or backpack sprayer and spot treatment.
For application to rights-of-way, buffer zones for protection of sensitive terrestrial habitats are not required; however, the best available application strategies which minimize off-site drift, including meteorological conditions (e.g., wind direction, low wind speed) and spray equipment (e.g., coarse droplet sizes, minimizing height above canopy), should be used.
The buffer zones specified in the table below are required between the point of direct application and the closest downwind edge of sensitive terrestrial habitats (such as grasslands, forested areas, woodlots, hedgerows, riparian areas and shrublands).
For tank mixes, consult the labels of the tank-mix partners and observe the largest (most restrictive) buffer zone of the products involved in the tank mixture and apply using the coarsest spray (ASAE) category indicated on the labels for those tank-mix partners.


For resistance management, GF-1966 is a Group 4 herbicide. Any weed population may contain or develop plants naturally resistant to GF-1966 and other Group 4 herbicides. The resistant biotypes may dominate the weed population if these herbicides are used repeatedly in the same field. Other resistance mechanisms that are not linked to site of action, but specific for individual chemicals, such as enhanced metabolism, may also exist. Appropriate resistance-management strategies should be followed.
To delay herbicide resistance:
Where possible, rotate the use of GF-1966 or other Group 4 herbicides with different herbicide groups that control the same weeds in a field.
Use tank mixtures with herbicides from a different group when such use is permitted.
Herbicide use should be based on an IPM program that includes scouting, historical information related to herbicide use and crop rotation, and considers tillage (or other mechanical), cultural, biological and other chemical control practices.
Monitor treated weed populations for resistance development.
Prevent movement of resistant weed seeds to other fields by cleaning harvesting and tillage equipment and planting clean seed.
Contact your local extension specialist or certified crop advisors for any additional pesticide resistance-management and/or integrated weed-management recommendations for specific crops and weed biotypes.
For further information or to report suspected resistance, contact Dow AgroSciences Canada Inc. at 1-800-667-3852 or at

Registered for culturesRatePreharvest Interval
Spring oats210 - 280 g
Winter flax280 - 415 g
Spring flax280 - 415 g
Sugar beets280 - 415 g90
Winter oats210 - 280 g
Rutabagas280 g83
Spring wheat210 - 280 g
Spring barley210 - 280 g