Prep II

Dow AgroSciences
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PREP II Herbicide is a selective postemergence herbicide for the control of hard-to-kill annual broadleaf weeds such as chickweed, wild buckwheat and cleavers in spring wheat (including durum), winter wheat, spring barley, and oats (tank mixes only) not underseeded with legumes. PREP II Herbicide is mixed with water and applied as a uniform broadcast spray. It is non-corrosive, nonflammable, and nonvolatile. PREP II Herbicide must be applied early postemergence, to the main flush of actively growing broadleaf weeds. Warm, moist growing conditions promote active weed growth and enhance the activity of PREP II Herbicide by allowing maximum foliar uptake and contact activity. Weeds hardened off by cold weather or drought stress may not be adequately controlled or suppressed and re-growth may occur. For best results, ensure thorough spray coverage of target weeds. See “DIRECTIONS FOR USE” section of this label for complete use details. PREP II Herbicide stops growth of susceptible weeds rapidly. However, typical symptoms (discolouration) 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 on weed sensitivity, weed size, crop competition, growing conditions at and following treatment, and spray coverage.

II Herbicide inhibits the production of the ALS enzyme in plants. This enzyme is essential for the production of certain amino acids which are essential for plant growth. PREP II Herbicide is a Group 2 mode of action herbicide.


Sensitive Plants
Do not apply PREP II Herbicide directly to, or otherwise permit it to come in 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.

Non-Target Sites
Do not apply where proximity of susceptible crops (e.g. canola and legumes) or other desirable plants is likely to result in exposure to spray or spray drift. See Environmental Hazards section of the label. This product has potential to leach. Do not apply excessive irrigation.

Tank Mixtures
In some cases, tank mixing a pest control product with another pest control product or a fertilizer can result in biological effects that could include, but are not limited to: reduced pest efficacy or increased host crop injury. The user should contact Dow AgroSciences Canada Inc. at 1-800-667-3852 or for information before mixing any pesticide or fertilizer that is not specifically recommended on this label. The user assumes the risk of losses that result from the use of tank mixes that do not appear on this label or that are not specifically recommended by Dow AgroSciences Canada Inc.

Spray Equipment Precaution
Do not apply through any type of irrigation system.


To Reduce Spray Drift:
1. Use nozzles delivering higher volumes and coarser droplets.
2. Use low pressures (200 to 275 kPa).
3. Use 100 L/ha of spray solution.
4. Spray when the wind velocity is 15 km/hr or less.
5. Spot treatments should only be applied with a calibrated boom to prevent over-application.

Equipment Clean-Up
Equipment used to apply PREP II Herbicide should not be used to apply other pesticides to sensitive crops without thorough cleaning. To avoid subsequent injury to crops other than cereals, all spraying equipment must be thoroughly cleaned both inside and out, as follows:
1. Immediately after spraying, drain. Any contamination on the outside of the spraying equipment should be removed by washing with clean water.
2. Rinse inside of tank with clean water and flush through booms and hoses using at least one tenth of the spray tank volume. Drain tank completely.
3. Add 1 L of household ammonia (containing a minimum of 3 % ammonia) per 100 L of water while filling the tank with clean water. Agitate and then briefly flush the boom and hoses with the cleaning solution. Top up with water making sure the tank is completely full and allow to stand for 15 minutes with agitation. Flush the boom and hoses and drain tank completely.
4. Remove nozzles and screens and clean separately with an ammonia solution (100 mL in 10 L water).
5. Rinse the tank with clean water and flush through the boom and hoses using at least one tenth of the spray tank volume. Drain tank completely. Note: If it is not possible to drain the tank completely, step 3 must be repeated before going onto step 4. Caution: Do not use ammonia with chlorine bleach. Using ammonia with chlorine bleach will release a gas with a musty chlorine odour which may cause eye, nose, throat, and lung irritation. Do not clean equipment in an enclosed area.




Application Directions
PREP II Herbicide may be tank mixed with glyphosate present as isoproylamine salt or dimethylamine salt to control volunteer glyphosate tolerant canola, wild buckwheat (up to 5 leaf) and top growth control of dandelion (up to 6 leaf stage) in addition to the labelled weeds controlled by PREP II Herbicide or glyphosate. Apply PREP II Herbicide at 100 mL/ha and glyphosate (present as isopropylamine salt or dimethyamine salt) at 450 g a.e./ha in 100 L water per hectare.

Application Timing and Cropping
Apply to actively growing weeds in the 2-4 leaf stage, except where noted above. Extreme growing conditions such as drought or near freezing temperature prior to, at or following time of application may reduce weed control. Only weeds which are emerged at the time of application will be affected. If foliage is wet at the time of application, control may be decreased. Under conditions of high weed density, control may be reduced.

PREP II Herbicide + glyphosate may be applied in the spring prior to seeding and no longer than 48 hours after seeding prior to any crop emergence. Fields treated with PREP II Herbicide in the spring may be planted to barley, oats, wheat, durum or summer fallowed.

Prior to August 1st: PREP II Herbicide + glyphosate may be applied to summer fallow fields and seeded in the following spring to barley, canola, oats, peas or wheat (including durum) or summer fallowed.
After August 1st, PREP II Herbicide + glyphosate may be applied to summer fallow fields and seeded in the following spring to barley, oats or wheat (including durum) or summer fallowed.

PREP II Herbicide + glyphosate may be applied to stubble or summer fallow fields after August 1st and prior to freeze-up and may be seeded to barley, oats or wheat (including durum) or summer fallowed.

Do not use in successive years at the same site.

Apply only one of the following treatments to the same site in the same year: a tank-mix of PREP II Herbicide and glyphosate (present as isopropylamine salt or dimethylamine salt, prior to planting or as the initial treatment in summerfallow) or any post emergent herbicide containing florasulam.

Mixing Instructions
1. Fill sprayer tank 1/2 full of water.
2. Start sprayer tank agitation.
3. Add the required amount of PREP II Herbicide
4. Add tank mix partner and continue to agitate.
5. Fill the sprayer tank with sufficient water to spray 100 L of spray mixture per hectare.
6. Follow sprayer directions and precautions as outlined above, especially when applying next to sensitive crops (e.g. canola and legumes).
7. Follow sprayer clean-up directions.

Preharvest/Grazing Intervals
Livestock may be grazed on treated crops 7 days following application. Do not harvest the treated crop within 60 days after application.

For resistance management, PREP II Herbicide is a Group 2 herbicide. Any weed population may contain or develop plants naturally resistant to PREP II Herbicide and other Group 2 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 PREP II Herbicide or other Group 2 herbicides within a growing season (sequence) or among growing seasons 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. To delay resistance, the less resistance-prone partner should control the target weed(s) as effectively as the more resistance-prone partner. Herbicide use should be based on an integrated weed management program that includes scouting, historical information related to herbicide use and crop rotation, and considers tillage (or other mechanical control methods), cultural (for example, higher crop seeding rates; precision fertilizer application method and timing to favour the crop and not the weeds), biological (weedcompetitive crops or varieties) and other management practices. Monitor weed populations after herbicide application for signs of resistance development (for example, only one weed species on the herbicide label not controlled). If resistance is suspected, prevent weed seed production in the affected area if possible by an alternative herbicide from a different group. Prevent movement of resistant weed seeds to other fields by cleaning harvesting and tillage equipment when moving between fields, and planting clean seed. Have suspected resistant weed seeds tested by a qualified laboratory to confirm resistance and identify alternative herbicide options. 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. 

Registered for culturesRatePreharvest Interval
Spring barley100 ml60
Spring wheat100 ml60
Winter wheat100 ml60