Home LEADProductsManufacturingNewsContact




APVMA code:  52202/1205 

Active Constituent(s):

480 g/L clomazone

solvent: 450 g/L liquid hydrocarbons 

Registered For:


 Commercial use

 Domestic use

Overview: For the control of certain annual grasses in rice. 

  SDS  (89 KB)

 LABEL (217 KB)

General Instructions


Magister® Herbicide is a short residual, water applied herbicide for the control of certain grass weeds indirect seeded rice crops. Plant uptake of Magister occurs through both the roots and the foliage. The movement of the active constituent clomazone within the plant occurs upward and outwards to the leaf. Clomazone is not downward systemic, nor translocated from leaf to leaf.




Clomazone, the active constituent in Magister, inhibits the biosynthesis of photosynthetic pigments of both chlorophyll and carotenoids. Accordingly the foliage of susceptible plants show signs of chlorosis (whitening or bleaching), followed by necrosis (browning).


Rice Safety


Transient bleaching of rice seedlings can occur in some circumstances particularly at the higher rates, in situations where rice seedlings protrude above the water level at time of application, and leaves are directly contacted by the concentrated emulsion or if the rice plant is under stress e.g. slime, salty soils or cold, deep water. In most cases seedlings usually recover rapidly. The variety Illabong is especially susceptible to bleaching. DO NOT apply to the variety Illabong established by the following methods - drill, sod or dry broadcast sown prior to permanent flood water. In cold conditions, the life of Magister in water can be extended which may increase the likelihood of bleaching in sensitive varieties. Under these conditions use the minimum rate specified for the crop growth stage.




Magister may be tank mixed with other herbicides to broaden the weed control spectrum compared to products applied alone.

Magister is compatible with the rice herbicides molinate, Shirquat* and other products containing paraquat, Stam* (propanil), Saturn*, Londax*, Taipan*, Viper* and the insecticides Dominex® Duo and chlorpyrifos.


Resistant Weeds Warning


Magister Herbicide is a member of the Isoxazolidinones group of herbicides. Magister has the inhibitors of carotenoid biosynthesis mode of action. For weed resistance management Magister is a Group Q Herbicide. Some naturally occurring weed biotypes resistant to Magister and other Group Q Herbicides may exist through normal genetic variability in any weed population. These resistant individuals can eventually dominate the weed population if these herbicides are used repeatedly. These resistant weeds will not be controlled by Magister or other Group Q Herbicides. Since the occurrence of resistant weeds is difficult to detect prior to use, FMC Australasia Pty Ltd accepts no liability for any losses that may result from the failure of Magister to control resistant weeds.




Add half the required volume of water in spray tank and start agitation. If tank mixing the correct order of addition is Wettable Powders or Water Dispersible Granules first, Liquid Suspensions (ie. Flowables) next, followed by Soluble concentrates and Magister and other Emulsifiable Concentrates last. Add remainder of water to tank and maintain good agitation at all times until spraying is completed.




Inappropriate application techniques can result in highly visible symptoms of spray drift. Magister can be applied

- prior to permanent water by ground boom spray only, and

- to permanent water by drip applicator at inundation of the permanent flood water, or by SCWIIRT application direct to the water surface of permanently flooded bays, via a properly equipped and calibrated ground sprayer, helicopter or fixed wing aircraft fitted with a Bickley boom.


Refer to the following relevant sections for more detailed information.


Application prior to permanent water:

Always apply Magister with either Shirquat* or with Stam* as per the Critical Comments. Apply as a broadcast spray using flat fan nozzles producing medium to coarse droplets with pressure not exceeding 250 kPa and with boom height no greater than 60 cm above the target. To minimise off-target movement use the lowest pressure and boom height that provides uniform coverage using 100-150 litres per hectare. Do not apply to wet soils or wet plants. Do not spray within 100 metres of residential or industrial properties or homes on neighbouring properties.


Application at inundation:

For drip treatment, dilute Magister at the ratio of 3 litres to 17 litres of clean tap water and apply this solution at a rate of 4 L/ha. A constant head siphon with a single CP4916 TeeJet flow regulator fitted with a disk orifice plate is recommended to apply the drip treatment into the floodwater at inundation. Refer to a

Magister calibration chart to guide selection of the appropriate orifice plate. The preferred method of inundation is to drip into individual bays or by a back fill system utilising a side channel, rather than top filling or flooding through the upper bays.


Application into permanent water - primer treatment in a split application:

It is essential that both the 1st and 2nd applications are applied. The 1st (pre-sowing) application suppresses weed germinations allowing the rice to develop to the secondary root stage at which time the 2nd (post-sowing) application is required for the control of emerging weeds, completing the herbicide program. If one application is applied without the other the technique will result in unsatisfactory weed control. For the 1st application follow the application directions in the section Application into permanent water - single application.


Application into permanent water - single application:

Apply by the SCWIIRT method using a tractor, 4 wheel agricultural motorbike, helicopter or fixed wing aircraft fitted with a Bickley boom. Apply to flood water from pre-sowing, up to the 2 leaf rice stage. Because of the solubility of clomazone and redistribution in water, Magister does not need to be applied right to the edges of the bay.


Ground / helicopter application:

Dilute the required amount of Magister in water (5 to 10 Litres/ha) and apply to flooded bay at a distance of 20 to 30 metres between runs. Position dripper nozzles no more than 50 cm from the water surface and maintain pressure at or below 200 kPa (30 PSI or 2 bar).


Fixed wing (Bickley boom) application:

Magister must only be applied from a fixed wing aircraft fitted with a Bickley boom which comprises the following:

Two nozzles mounted on droppers, one either side with droppers positioned just outside the first boom hanger (28-35% of wingspan);

Dropper length approximately 40-60 cm or lower below the trailing edge of the wing;

Solid stream nozzles with bore sufficient to apply desired volume at a pressure of 240 to 310 kPa (35 to 45 psi);

Nozzles orientated rearwards and parallel to the airstream;

Check valves (Spraying Systems diaphragm type 12328, 3/4 inch) located behind nozzle to eliminate “trailing” shut off;

Spray at a maximum wheel height of 2m above the field surface.

Swath widths of approximately 25 m are recommended.


Dilute the required amount of Magister in water (10 to 20 Litres/ha) add 41-A spray drift retardant at the rate of 60 g per 100 litres of spray solution and apply to flooded bay. Before commencing aerial application to contoured bays evaluate the layout of the bays to be treated and select the optimum flight pattern to ensure all bays receive the recommended rate of Magister.


Water Management


Application prior to permanent water in drill and sod sown rice:

Refer to the Critical Comments for more detailed information.


Application to permanent water:

It is essential to prevent water movement for at least 3 days after treatment of Magister. Floodwater must cover all ground to a sufficient depth at application to maintain water cover until water can be added after the 3 day period. Water levels should then be restored and a continuous uniform depth maintained to assist in weed control. For best results when applying by SCWIIRT, lock up bays prior to application to cease water movement.

Do not drain rice water into regional drains within the withholding period, after Magister or Magister tank mix application (minimum 28 days for Taipan*), as defined by the Local Irrigation Authority and/or the NSW Environment Protection Authority or for 10 days, whichever is the greater.


Crop Rotation Recommendations


Refer to label for details.


Off Target Whitening


Magister can cause whitening of sensitive plants (ie. some species of trees, shrubs, ornamentals, agronomic crops, vines and fruits and vegetables) either by spray drift or by volatilisation following product dilution. The effects may last a few weeks and plants usually grow out of it with no long term effect. This phenomenon is unlikely to occur following application into permanent water in rice. However drift could occur following aerial application through the Bickley boom or by ground application when used prior to permanent water. The following general steps should be taken to minimise the likelihood of this whitening occurring: -refer to the specific use patterns for more detailed recommendations.



1. Ensure that when the product is being diluted prior to application that it is done away from desirable plants such as roses, ornamentals and vines.

2. DO NOT empty or clean application equipment near homes or sensitive plants.

3. Remove contaminated clothing before entering areas where sensitive plants exist e.g. homes, nurseries or green houses.

4. Apply only with calibrated equipment.

5. DO NOT apply with a boom spray except when applying as per the Application prior to permanent water: situation.


Application prior to permanent water:

1. Do not spray within 100 metres of residential or industrial properties or homes on neighbouring properties.

2. Do not apply by air.

3. Apply only with calibrated equipment.

4. Apply as a broadcast spray using flat fan nozzles producing medium to coarse droplets with pressure not exceeding 250 kPa and with boom height no greater than 60 cm above the target.

5. Apply to dry soils in 100-150 L water per hectare.

6. Do not apply to wet soils and/or wet plants.


Application to permanent water:

1. Apply only with calibrated equipment.

2. Refer to Application section for specific details. Apply as a drip at inundation using a constant head siphon or

3. Apply to flooded bays using the standard SCWIIRT method by tractor, 4 wheel agricultural motorbike or helicopter using 5-10 litres of water per hectare or

4. Apply as an aerial SCWIIRT method by fixed wing aircraft fitted with a Bickley boom, using 10 to 20 litres of water per hectare. For application by fixed-winged aircraft only use the Bickley boom SCWIIRT method.

5. Bays should always be sprayed downwind from susceptible crops or properties or environmentally sensitive areas.

6. Do not spray within 300 m upwind or 50 m downwind of susceptible crops or properties or environmentally sensitive areas.

7. Do not spray right to ends and sides of bays to be treated.

8. Ensure nozzles are shut off before leaving last bay to be treated.


Protection of Crops, Native and other Non-Target Plants


DO NOT apply under meteorological conditions or from spray equipment, which could be expected to cause spray drift onto nearby susceptible plants, plants (including residential and other gardens), adjacent crops, crop lands or pastures.


Protection of Wildlife, Fish, Crustaceans and Environment


DO NOT contaminate streams, rivers or waterways with Magister or used container.



Storage and Disposal


Do NOT store near (or allow to contact) fertilisers, fungicides or pesticides. Store in the closed, original container in a well ventilated area, as cool as possible. Do not store for prolonged periods in direct sunlight. Store in a locked room or place away from children, animals, food, feed stuffs, seed and fertilisers.


Spillage - In case of spillage, confine and absorb spilled product with absorbent material such a sand, clay or cat litter. Dispose of waste as indicated below or according to Australian Standard 2507 - Storage and Handling of Pesticides. Do NOT allow spilled product to enter sewers, drains, creeks or any other waterways. The method of disposal of the container depends on the container type. Read the Storage and Disposal instructions on the label that is attached to the container.


Safety Directions


Harmful if inhaled or swallowed. Will irritate the eyes and skin. Avoid contact with eyes and skin. Do not inhale vapour. When opening the container and preparing spray, wear cotton overalls buttoned to the neck and wrist (or equivalent clothing), elbow length nitrile gloves and face shield or goggles. When using the prepared spray, wear cotton overalls buttoned to the neck and wrist (or equivalent clothing) and elbow length nitrile gloves. If product in eyes, wash it out immediately with water. Wash hands after use. After each day’s use, wash gloves, face shield or goggles and contaminated clothing.


DISCLAIMER: This is not the MAGISTER label. To view or print the label for this product, click the "MSDS/Label" tab at the top of this page. Always follow label instructions.


For specialist advice in an EMERGENCY only phone 1800 033 111, TOLL-FREE, ALL-HOURS, NATIONWIDE


To the topTo the top




Alphabetical index  Ι  Sitemap  Ι  Disclaimer  Ι  Sales terms and conditions  Ι  Useful links