500G Tristar


For the control of broadleaf weeds in wheat, barley and oats, and for use in conservation tillage.



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Active Ingredient: 750g/kg tribenuron-methyl

Chemical Group: Sulfonylurea – GROUP B

Formulation: Water dispersible granule To get the best crop establishment or new pasture, Tristar plus glyphosate will give you far greater results than using glyphosate alone. Tristar controls a range of difficult-to-control broadleaf weeds, helping to improve establishment and yield.

PRODUCT INFORMATION: Tristar is a selective post-emergence herbicide for control of weeds in wheat, barley and oats. It is non-corrosive to equipment, non-flammable and non-volatile. Best results are obtained when Tristar is applied to young, actively growing weeds. Tristar stops growth of susceptible weeds. However, typical symptoms (discolouration) of dying weeds may not be noticeable for 1-3 weeks after application. Warm, moist conditions following treatment promote the activity of Tristar while cold, dry conditions delay the activity of Tristar. DO NOT apply Tristar to crops that are stressed by severe weather conditions such as drought, frost, water saturated soil, disease or insect damage as crop injury may result. Severe winter stress, drought, disease or insect damage following application may also result in crop injury.

Direction for Use: Measure the correct amount of Tristar required to the required volume of water. Continuous agitation is required to keep the product in suspension. Use mixture within 24 hours of preparation. Always add non-ionic surfactant unless mixing with another product which contains surfactant



IT IS AN OFFENCE for users of this product to cause residues exceeding the relevant MRL in the New Zealand Food Notice: Maximum Residue Levels for Agricultural Compounds.

Mixing Instructions: Measure the correct amount of Tristar required for the area to be sprayed and add to the required volume of water. Continuous agitation is required to keep the product in suspension. Use Tristar spray mixtures within 24 hours of preparation, as product degradation may occur.

Surfactant: Always add a non-ionic surfactant unless mixing with another product which contains surfactant.

Spray Volumes: Use a properly calibrated sprayer applying a minimum of 60 litres per hectare. Avoid overlapping and shut off spray booms while starting, slowing or stopping, or injury to the crop may result.

Rate of Application: Wheat, Barley, Oats Apply 15 – 25 grams Tristar per hectare plus surfactant at any time after the crop is in the two leaf stage (Zadoks G.S. 12), but before the “boot” stage (Zadoks G.S. 45). For best results apply to small actively growing weeds (less than 5cm tall or across) before crop canopy closes in. Where treatment is delayed or where weeds are not actively growing due to adverse conditions, weeds may only be stunted or suppressed.

DO NOT spray Tristar
on cereals undersown with lucerne or white clover.

Weeds controlled at 15g/ha Weeds controlled at 25g/ha Weeds not controlled**
Californian thistle*, Scotch thistle, Wild turnip, Chickweed, Shepherd’s purse, Fathen, Spurrey, Scarlet pimpernel, Willow weed Amaranthus (redroot), Sheep’s Sorrel, Twin cress, Wireweed Cleavers, Speedwells, Wild oats

*Delay application until after the majority of thistles have emerged and are at the rosette stage (10-15cm tall). Thistles which emerge after spraying will not be controlled.

** If these weeds are a problem add a herbicide registered for the control of these species.

Tank Mixtures – Barley Only
Tristar at 15g/ha may be tank mixed with certain herbicides. Refer to the specific product label for rates and recommendations.

Conservation Tillage:
(Brassicas, cereals, maize, new pastures, peas, potatoes, squash). For control of certain broadleaf weeds including clovers, sheep’s sorrel, yarrow and ragwort, use Tristar at 40g per hectare in combination with glyphosate at label rates plus a penetrant before the crop is sown. DO NOT sow crops within 14 days of applying Tristar. DO NOT sow brassica species into Tristar treated areas if soil pH exceeds 6.5.

DO NOT USE TRISTAR PRIOR TO PLANTING FODDER BEET. Tolerance to other crops (grown through to maturity) should be determined on a small scale before sowing into larger areas. DO NOT apply Tristar within 2 months after a lime application. Lime may be applied 14 days after Tristar has been applied.

Caution: Ragwort plants may become more palatable following spraying and stock should be removed until the treated plants brownout.

Compatibility: Tristar is compatible with most commonly used cereal herbicides, insecticides and fungicides. Resistant Weeds Warning: Tristar contains a GROUP B herbicide belonging to the sulfonylurea group of chemistry, with the inhibition of ALS mode of action. Naturally occurring biotypes resistant to sulfonyl urea herbicides are known to exist.

These resistant weeds will not be controlled by Tristar or other sulfonyl urea herbicides. To prevent or delay the development of resistant weeds use Tristar in tank mixes (if appropriate) and/or rotations with herbicides having different modes of action effective on the same weed species. Since the occurrence of resistant weeds is difficult to detect prior to use, no liability will be accepted for any losses that may result from the failure of Tristar to control resistant weeds.

Sprayer Decontamination:
To avoid subsequent injury to crops other than wheat, barley or oats, immediately after spraying thoroughly remove all traces of Tristar from mixing and spray equipment as follows:

  1. Drain tank, then flush tank, boom and hoses with clean water for a minimum of 10 minutes.
  2. Fill the tank with clean water and add 1 litre chlorine bleach (containing 3% sodium hypochlorite) per 100 litres of water. Flush throughout with agitation; then drain.
  3. Repeat step 2.
  4. Nozzles and screens should be removed and cleaned separately. To remove traces of chlorine bleach, rinse the tank thoroughly with clean water and flush through hoses and boom.

Registered Pursuant to the ACVM Act 1997, Approval No P7585

500G Tristar