Control Methods – What Works

Preventing Spread of Wheel Cactus

Preventing further infestations of Wheel Cactus is vitally important to the eradication of this weed. Therefore, the most critical action is to prevent animals from eating the fruit and dispersing the seeds elsewhere.

The most effective methods, therefore, are to:

  • kill plants before maturing to fruit bearing age
  • kill all mature fruiting plants
  • remove fruit and dispose by incineration or transfer to the tip

How We Kill Wheel Cactus

Please exercise caution

  • wear protective clothing, gloves, boots and glasses to protect against the cactus prickles and herbicide
  • seek advice on how to correctly inject the cactus pads to prevent inhalation, ingestion or absorption of the herbicide

Very Small Plants (less than 50 mm)

  • squash them under foot totally (until unrecognisable)

Small – Medium Plants

  • inject outer (uppermost) wheel with 2ml of glyphosate (Roundup mixed at rate of 33.5%)
  • dig them up and dispose of the entire plant
  • or take to them to the Maldon Recycle Station (Tip) for disposal (free of charge)

The tool we currently use is a perfect design for digging up small to medium sized plants and it can be purchased for a reasonable price from a common hardware chain store. The tool has two parallel points which can be used to uproot the plant and also has a flat blade which can be used to squash or cut the lobes.

Hoe used by Tarrangower Cactus Control Group

Hoe used by Tarrangower Cactus Control Group

(Digging tools and buckets can be borrowed from the Tarrangower Cactus Control Group)

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Large Plants

  • inject all outer wheels (lobes) with 4ml of herbicide (glyphosate)

(Injecting guns can be borrowed from the Tarrangower Cactus Control Group)

Very Large Plants

  • remove the fruit to prevent birds and other animals eating and spreading the seeds
  • ideally incinerate the fruit or dispose of it within a sealed container and then in rubbish bin
  • inject all outer wheels (lobes) and second in if possible with 4ml of herbicide (glyphosate)

Injecting Techniques

Details of the injecting equipment used by the Tarrangower Cactus Control Group can be seen here. It is purchased through rural supply outlets.

The key to a successful kill of a plant is using the correct injecting technique. The injector is inserted into the outer lobe (wheel), pushed well into the lobe and then pulled halfway out to make a pocket for the herbicide. The gun then delivers a 4ml dose of glyphosate into the lobe. Making this pocket is very important as without it the herbicide may shoot out of the lobe when the injector is removed. On large plants injecting the second lobe increases the chances of a faster knockdown and successful kill.

Small plants can also be injected leaning the plant against a shoe for support and then injecting 1-2ml of glyphosate into the top lobe.

The first slideshow indicates how to correctly inject from the side of the lobe of a wheel cactus to make a pocket for the glyphosate.

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This next slideshow has another method of injecting where the injector is inserted into the front of the lobe and then pushed across it to make a pocket.

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This third slideshow indicates how to inject quite small cactus when removal is not feasible because there are hundreds of them or the terrain is too difficult to carry buckets to remove them.

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The last slideshow has some images of incorrect techniques, mainly stabbing the plant rather than making a pocket for the glyphosate. When injected or stabbed the plant will weep sap. This is not an issue when there is a pocket deep inside the lobe for the glyphosate to prevent it seeping out. However, when a plant is stabbed the glyphosate is just under the skin and will be exuded out with the sap. In addition, wheel cactus is very resilient. It can isolate a stab wound and heal around it.

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The next photos show plants that were stabbed, rather than injected to form a pocket. Notice how they have healed around the stab wound while correctly injected plants surrounding them have died in the same 3 months.

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Details of the injecting equipment used by the Tarrangower Cactus Control Group can be seen here.