How is Lantana a problem?
All forms of lantana are thought to be toxic, with the red-flowered forms being the most dangerous to stock. Lantana poisoning in cattle is quite common and causes major economic losses. During droughts, or when other feed is scarce, stock are also more likely to graze lantana.
This slow and painful death is due mainly to liver insufficiency, kidney failure, and in some animals, myocardial damage and internal paralysis.
Lantana is also highly toxic to humans, it can cause serious illness and death. All parts of the plant, particularly the green berries, are poisonous if ingested. Lantana can cause vomiting, diarrhoea, muscular weakness and respiratory distress. The plant is also a skin and eye irritant.
Lantana is a problem, because it forms a dense thicket. Lantana is a lalopathic, releasing chemicals into the surrounding soil to prevent seed germination, notably of the native flora, so that it eventually takes over native bushland. It spreads quickly and can resist a range of climates.
Control and Management
A range of control methods utilising Integrated Weed Management is needed to effectively control Lantana. Common methods include the following:
- Manual control
- Mechanical control
- Pasture improvement
- Grazing management techniques
Consideration needs to be given to seasonal variables. In the case of herbicide use, the plant needs to be actively growing to achieve optimal uptake.
Eradication is a multi step process, because the plant is hardy and resilient, it will take effort to get it under control. Following up with either herbicides, manual control or mechanical control is essential to get on top of regrowth or new seedlings. The area can quickly become reinfested rendering the initial efforts useless.
For smaller areas it is possible to hand cut or hand pull plants. It’s also an option for hard to reach areas.
More commonly mechanical control is utilised in extensive areas of growth. Several machines are capable of effectively removing larger bushes quickly and effectively.
On steep country or near a water course it’s possible to cause erosion by exposing the ground. Extra care needs to be taken in these situations.
For steep and hard to get at areas hiring a contractor, with specialist equipment, could also be an option. For example a remote controlled machine could be the safest and most effective method of removal.
Pasture establishment and grazing
Once the ground has been cleared, it needs to be followed up with a herbicide treatment, along with the introduction of another species of plant. Commonly it’s at this point a pasture is established.
A useful machine for this application is a double disc seed drill. The discs allow the machine to roll across the ground without hooking up roots or trash as a tine drill would do. Also it’s able to penetrate the ground and sow seed without the need for ground preparation. Again leaving the soil intact, without disturbing weed seeds or plant roots.
It’s recommended to select a species of grass that is well suited to the area and grows vigorously, which will then in turn compete with regrowth seedlings. Grazing stock can also assist with trampling further weakening emerging seedlings.
Continual monitoring of the new pasture with either spot spraying or further mechanical control is essential to ensure the grass becomes the dominant species.
Consultation with a herbicide supplier is needed, to best select a chemical that’s most effective, according to the species of lantana being treated.
A number of machinery options are available for spraying. It may be a ute mounted tank is a good option, or for undulating country, a sprayer tank mounted on a tractor 3 point linkage could be a safer option.
From February until the first frost is the ideal time to treat mature lantana. It’s important that the plant is actively growing and less than two metres high.
Accuracy during application is paramount to avoid damage to surrounding native species and pasture grasses.
For best results, spray the lantana thoroughly on all foliage and stems to point of run-off. Apply evenly to ensure the herbicide penetrates through the brush to hidden foliage with a recommended spraying pattern of side-by-side. To ensure complete coverage, also wet the soil around the base of the plant with herbicides to achieve best results. This will help with uptake through the root system and residual control of seedlings that may germinate.
The affects of spraying your lantana can take a few weeks to appear, with the death of the plant taking around 9-12 weeks. For some herbicides, death of the plant could take 3-6 months.
Signs of damage can include: brownout of leaves, defoliation, wilting, yellowing, dieback of the leaves.
Regrowth from slashing or mulching is best treated when the plant reaches 30 to 100cm. At this stage access will be much easier and less chemical needed to treat the area. Typically it takes three treatments after the initial application to complete the eradication.