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.
Gamba Action Program
The Gamba Action Program is now closed.
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.
Follow the instructions
Under the law, you must follow instructions on the herbicide label.
For more advice on using herbicides, go to page eight of the NT Weed Management Handbook .
You should read the safety data sheet of any herbicide you use for 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.
The Poisons Information Centre can give you advice in case of a medical emergency.
Phone: 131 126
The herbicide provided through the Gamba Action Program is called glyphosate.
You will be provided with Glyphix® 360, which contains 360g per litre of glyphosate as the active ingredient.
You can get the herbicide instructions on the Relyon Australia website.
Always refer to the label on the bottle before mixing herbicide.
How to mix glyphosate
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 litre 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 weak 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
- consider using a 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:
- Adjust your nozzle to produce medium to heavy size droplets so you can get full coverage of the plant while reducing spray drift.
- Coat the entire plant - each stem of a gamba grass tussock is an individual plant, if any stems are missed the plant can recover.
- Spray until herbicide drips from the leaves to make sure it gets through the fur on the leaves.
- Don't spray in windy conditions to avoid damage to non-weed plants nearby.
- Use only aquatic approved glyphosate near watercourses to avoid harming plants and animals in the water.
- 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 15m of roads, tracks, property boundaries, houses, sheds and other infrastructure must be controlled.
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.
Slide-on spray units
Slide-on spray units are available from the Freds Pass Reserve distribution centre.
You can check if a spray unit is available by calling 0427 272 586 after 30 November 2020.
Slide-on spray units:
- are lightweight and suitable for the back of a ute or ATV
- come in 50, 100 or 200 litres
- have a 1 to 2m hose
- use 12-volt DC (car battery) power (battery not included).
You should book in advance through the Weed Management Branch.
- 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.
Last updated: 15 April 2021
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