Invasive alien plant control procedure:
- Invasive alien plants are plants that grow outside of their natural habitat or country of origin and due to their ability to outperform and outgrow indigenous plant species; they establish themselves in this non- native habitats. They were introduced either by accident or on purpose i.e. practical purposes
Alien plants:
- Are highly adaptable, vigorous growers that invade a range of ecological niches;
- Use water more than their indigenous counterparts, reducing South Africa’s water resources;
- Threaten our biodiversity by replacing indigenous and endemic vegetation. This will result in a loss of insect species that are dependent on these plants and the ripple effect loss of birds, reptiles and mammals that feed on those insects;
- Invade agrarian land which is productive and make it dormant;
- Exacerbate the intensity of fires, flooding, erosion, siltation and other environmental concerns;
- Are often toxic to humans or animals.
Three phased control programme:
Initial control
- It requires an aggressive remedial approach with the aim to drastically reduce the number of alien invader vegetation to acceptable and manageable levels.
Follow up control
- It is important to control re-growth or new seedlings. Follow can be done as soon as re-growth or seedlings are spotted. It may be in the same or the following season depending on climatic conditions.
Maintenance control
- Monitoring of alien vegetation should continue on regular basis to identify any re-growth or seedlings. It is expected that infestation densities would have been dramatically reduced at this stage and that only individual plants may appear from time to time. It is recommended that any re-growth be manually removed to avoid the use of chemicals unnecessarily.
Methods to control invasive alien plants:
Mechanical methods
- It is felling, removal of invading alien plants, often in conjunction with burning;
- Equipment that can be used range from hand-held instruments i.e. chainsaws, slashers, axes to power driven tools such as chainsaws and brush cutters.
Chemical methods
- Herbicides should be applied to prevent sprouting of cut stumps or destroying seedlings after felling or burning;
- Herbicides can be used on grasses or broad leaved species;
- Effective and safe use of herbicides requires high level training to personnel; Environmentally safe herbicides and pesticides should be used.
Biological control
- Using species specific insects and diseases from the alien plant, insect of animal’s country of origin).
Integrated control
- Combinations of the above three approaches. Often an integrated approach is required in order to prevent enormous infestations.
Mechanical and chemical method
Basal bark
- Application of suitable herbicide in diesel can be carried out to the bottom 250 mm of the stem. Applications should be by means of low pressure, coarse droplet spray from a narrow angle solid cone nozzle.
Hand pull
- Grip the young plant low down and pull out (using gloves).
Ring barking
- Bark must be removed from the bottom of the stem to a height of 0.75 – 1.0m. All bark must be removed to below ground level for good results. Where clean debarking is not possible due to crevices in the stem or where exposed roots are present, a combination of bark removal and basal stem treatments should be carried out. Bush knives or hatchets should be used for debarking.
Frill
- Using an axe or bush knife. Make angled cuts downward into the cambium layer through the bark in a ring. Ensure to affect the cuts around the entire stem and apply herbicide into the cuts.
Cut stump treatment
- Stems should be cut as low as practical as stipulated on the label. Herbicides are applied in diesel or water as recommended for the herbicide. Applications in diesel should be to the whole stump and exposed roots and in water to the whole stump and exposed roots and in water to the cut areas recommended in the label.
Stem injection
- Punch downward slanting holes into the main stem using a sharpened metal spike. Space holes around the entire circumference of lower stems. Inject the herbicide directly to the plant Follow the label recommendations.
Maintenance control
- The direction for control should be in a downstream direction, meaning that the initial control should start upstream and terminate downstream;
- High priority areas should be cleared first;
- Areas with low infestations should be considered then move to areas of high infestations since control of this areas will be rapid;
Medical examination
- All workers must do entry medicals before work commence and exit medicals when the project has been completed. Medicals will be valid for one year.
First aid kit
- A first aid kit, fully stocked must be easily accessible at all work sites.
- At two persons per team should have a first aid certificate?
Personal protective equipment and clothing (PPE)
- Environmental workers and alien plant control teams must be protected against all hazards identified in the risk assessment.
- PPE required protecting eye injuries, hand injuries, falling objects and rolling rock, slipping and falling, UV radiation, bee stings, incest and snake bites etc.
- PPE as prescribed by the MSDS.
- PPE required for work on /near water bodies;
- PPE must be provided with consideration to the hazards exposure to dangerous animals;
- PPE must be replaced when it becomes ineffective through wear and tear.
Herbicides and correct application methods
- Workers should be informed of the risk of working with the selected chemicals and how to avoid that risk
- Only registered herbicides and application methods may be used;
- The method and rate of application must be done according to label under supervision of a qualified / experienced operator;
- Clean good quality water must be used;
- Herbicide application must not take place in unsuitable weather conditions e.g. application in windy conditions or directly after rain event while the plants are wet.(causing dilution of the herbicide)
- Use water provided on site -do not collect or dispose of water in a natural watercourse;
Environmental
Indigenous plants and animals
- Indigenous plants and animals (birds, snakes, mammals, insects and their nesting/ breeding and feeding sites must not be harmed;
- No animals may be poached;
Erosion control and flooding prevention.
- Where large areas of top soil is exposed due to the removal of alien plants, erosion control measures must be done to encourage indigenous plants to re-vegetate;
- Preserve indigenous plant cover, take precautionary measures to protect stabilising plants,
- Areas identified where stabilization is required must be re-vegetated and seeding should be done if required.
- All dead plant material must be removed from river beds to prevent accumulation off dead material during rain storms.
Fire Precautions
- Fires and smoking should not be allowed on site; when exceptions are made precautionary measures must be applied: i.e. Fires only allowed in safe demarcated areas.
- The burning of excessive plant material may only be allowed after all precautions have been done and the necessary permits obtained.