Gamba grass

Free help to control gamba grass

You can get free herbicide, spray equipment loans and weed management advice from the Northern Territory Government to help control gamba grass in the Top End, including Katherine.

This is called the Gamba Action Program.

The 2017 to 2018 program is now closed. Read about the results of the 2017 to 2018 Gamba Action Program (932.5 kb).

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How to get help

You can get free herbicide and borrow spray equipment to help control an infestation of gamba grass.

Step 1. Find a loan location

Read below to get the contact details for loan equipment.

Step 2. Draw a property plan

At the loan location you will be asked to draw a plan of your property that will be used to decide how much herbicide you need.

Include the following in your property plan:

  • property location
  • land size
  • location and size of gamba grass infestations.

Step 3. Fill in an agreement

At the loan location you will need to fill in an agreement to get herbicide or borrow equipment.

Step 4. Complete a survey

At the loan location you will be given a survey to fill in about the Gamba Action Program.

Read below about using spray equipment.

Herbicide safety

A herbicide is a chemical that destroys or slows the growth of plants, especially weeds. The herbicide used to control gamba grass is called glyphosate.

You must correctly use herbicides as they can cause immediate and long-term illnesses.

There are laws and instructions you must follow when using herbicides, these include Commonwealth and Northern Territory law.

Go to the Australian Government website to read about Commonwealth laws.

Read more about NT herbicide laws.

Follow the instructions

Under the law, you must follow instructions on the herbicide label.

Go to a copy of the Ken-up Aquatic 360 herbicide instructions (548.8 kb).

For more advice on using herbicides go to page eight of the NT Weed Management Handbook (1.3 mb).

Read the material safety data sheet (174.6 kb) for more information including:

  • potential health effects
  • first aid
  • personal protective equipment
  • spill and disposal procedures.

Using herbicides in the environment

You should follow these guidelines for safe herbicide use:

  • don't spray plants other than declared weeds as glyphosate can kill plants other than gamba grass if it comes into contact with them
  • don't spray in windy conditions as spray drift can damage plants you are not targeting
  • don't contaminate dams, waterways or sewers with glyphosate.

Poisons advice

The Poisons Information Centre can give you advice in case of a medical emergency.

Phone: 131 126

Using glyphosate on gamba grass

The herbicide provided through the Gamba Action Program is called glyphosate.

How to mix glyphosate

You will be provided with Ken-up Aquatic 360, which contains 360g per litre of glyphosate as the active ingredient.

You must dilute the glyphosate before you apply it to gamba grass.

When you dilute glyphosate you must use only the described ratio of water to herbicide.

For glyphosate 360g/L provided, mix 1 litre of concentrate with 100 litres of clean water for a 1% ratio.

Ratios that are too strong can burn leaves and may not kill the whole plant.

Ratios that are too week may not kill the plant.

You must do all of the following:

  • mix herbicide with rainwater, tap water or good quality bore water
  • not use creek or dam water that may contain clay or organic matter
  • consider adding a wetting agent to help the glyphosate get through the hairy surface of gamba grass leaves
  • use marker dye to show if you missed any weeds.

Planning to spray your property

You should consider the following when you are planning to spray your property:

  • spray only when leaves are green and at least 40cm long - glyphosate can be absorbed only by growing leaves and stems
  • spray early in the Wet Season, before it reaches full height - this gives better results for less herbicide and effort
  • before spraying, consider removing tall, dry grass stems and encouraging new growth of mature gamba grass - controlled burning or slashing may help with this
  • allow time for slashed, mown, grazed or burnt gamba grass to grow new leaves before spraying
  • always spray before seeding
  • gamba grass is still susceptible to herbicide when flowering.

How to spray

The following is a checklist for how and when to spray:

  1. Adjust your nozzle to produce medium to heavy size droplets so you can get full coverage of the plant while reducing spray drift.
  2. Coat the entire plant - each stem of a gamba grass tussock is an individual plant, if any stems are missed the plant can recover.
  3. Spray until herbicide drips from the leaves to make sure it gets through the fur on the leaves.
  4. Don't spray in windy conditions to avoid damage to non-weed plants nearby.
  5. Use only aquatic approved glyphosate near watercourses to avoid harming plants and animals in the water.
  6. You should spray in the mornings, and at least an hour before rain as it takes an hour for plants to absorb the herbicide.

Where to prioritise

You should prioritise fire risk areas.

All gamba grass within 50m of houses, sheds and other infrastructure should be controlled and removed.

Control all gamba grass in fire access trails. This also prevents spread to adjoining properties.

Eradicate isolated plants and outbreaks to prevent establishment in new areas.

Control plants which are likely to cause further gamba grass spread, such as on the edge of tracks.

Ensure your control efforts do not contribute to unintended seed spread.

Follow up after your spray

If plants have not wilted and yellowed within four to seven days you will need to spray again.

Check all treated areas for missed plants, regenerating plants and new seedlings

You may need three or four rounds of spraying for good results in the first year of control.

Follow up control in subsequent years will also be necessary.

Using spray equipment

There are two types of spray units available for you to borrow for free to help control a gamba grass infestation on your block.

Slide-on spray units can be used from the back of a quad bike or ute.

Quikspray units that may be better suited to larger or hard to access gamba grass infestations are also available.

Slide-on spray units

Slide-on spray units:

  • are lightweight and small
  • can fit on the back of a utility vehicle
  • come in 50, 100 or 200 litre sizes
  • have 6m of 8mm hose
  • use a 12 volt car battery - the battery is not included.
How to use a slide-on spray unit

When you fill the tank make sure half the final volume of water is added to the tank before you add concentrated herbicide. This allows proper mixing.

All spray equipment including tanks must be rinsed and flushed with clean water before you return them.

Quikspray units

You should book in advance through the Weed Management Branch or Bushfires NT in Batchelor.

Quickspray units:

  • are large and require a trailer or ute
  • come in 200 or 600 litre units
  • have options of twin reel sprayers
  • have a retractable 50m or 100m hose
  • run on unleaded petrol.
How to use Quikspray equipment

When you fill the spray tank make sure half the final volume of water is added to the tank before you add concentrated herbicide. This allows proper mixing.

Do not adjust the settings on the Quikspray unit. These have already been set to minimise the risk of spray drift.

Only use unleaded petrol for the pump motor for the tanks.

Make sure the hose does not come into contact with your car, pump motor exhausts or hot or sharp objects.

Don't over-retract the hose, as the stopper can be damaged.

Make sure you secure spray guns before transporting the unit.

Loan location contacts

These locations can provide free herbicide and/or spray equipment for gamba grass control.

LocationAddress Opening hoursPhone
Freds Pass Sport and Recreation Reserve Bees Creek Road
See location map (202.5 kb)
Monday and Friday only
7.30 to 10.30am
2.30 to 5.30pm 
0427 272 586
Territory Wildlife ParkCox Peninsula Road
Berry Springs 
 0401 114 912
Bushfires NT42 Cameron Road
 08 8976 0098
Coomalie Community Government Council - herbicide only141 Cameron Road
 08 8976 0058
Katherine Weed Management Branch depot
13 Crawford Street
Friday 1pm to 4.15pm 08 8973 8857
Dundee  08 8978 2107
Wagait BeachWagait Beach Shire Council 0427 133 959
DarwinWeed Management Branch depot
40 Wallaby Holtze Road
On request08 8999 4567
Beatrice Hill Volunteer Fire BrigadeBeatrice Hill 0457 212 309

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Last updated: 20 September 2018