Prevention

The first step in weed prevention, and the most cost-effective means of managing weeds, is to prevent potential weeds entering Australia. More than 70% of plants now considered to be weeds in Australia were intentionally imported for garden or agricultural use.

Because Australia is an island it has some protection from invasion by foreign plants. However, with increased trade and human movement across our borders comes an increased potential for movement of plants. Plants, or parts of plants such as seeds, are small enough to enter Australia in or on luggage, cargo, mail, equipment, vehicles, food, animals or even people.

The Australian Government has a range of legislation that regulates the import of plants into Australia, including potential new weeds. The legislation is enforced at Australian borders by the Department of Agriculture and Water Resources and the Australian Border Force. A plant may be allowed or not allowed entry, or may require a permit. People planning to import any plants or plant material need to check on the requirements under the legislation before they import.

Australian Government legislation (laws) that control the importation of potential weeds

The Australian Government is responsible for international border protection, including regulating the import and export of plant material. The Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act) and the Biosecurity Act 2015 and its subordinate legislation regulate the import of live animals and plants into Australia. Prior to any new plant being imported into Australia, the plant must be assessed for its potential impacts under the Acts. The Australian Government administers both Acts with the cooperation of the states and territories.

• Environment Protection and Biodiversity Conservation Act 1999
• Biosecurity Act 2015 

Assessment for weediness of plants that are not currently in Australia

Plant species are assessed through a Weed Risk Assessment system  to determine whether they are safe to be allowed into Australia.

The Weed Risk Assessment system administered by the Department of Agriculture and Water Resources evaluates the potential weed risk to both the environment and agriculture of a new plant species proposed for import under the Biosecurity Act 2015. The Weed Risk Assessment system utilises a science-based risk assessment methodology to provide quarantine policy advice and recommendations regarding requests for the import of new plant species.

For the purposes of assessment under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act), it was agreed that the Weed Risk Assessment system adequately assessed the potential environmental risk of plants. The Live Import List established under the EPBC Act is taken to include any plant species allowed to be imported under Biosecurity Act 2015. This means that a proposed new plant import is assessed through one agreed process.

Lists and databases of plants or plant material prohibited from import into Australia

The Department of Agriculture, Water and Environment regulates the import of seeds from plant species into Australia through the Biosecurity Act 2015.

Species that have been assessed as posing a weed or quarantine risk are listed as not permitted on the Department of Agriculture and Water Resources Biosecurity Import Conditions system (BICON). However, large numbers of plant species are yet to be assessed and are not listed.

The Environment Protection and Biodiversity Conservation Act 1999’s Live Import List is taken to include any plant species allowed to be imported under the Biosecurity Act 2015.

In addition, the Environment Protection and Biodiversity Conservation Act 1999 regulates the export and import of species protected under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). CITES was established to prevent international trade from threatening species with extinction.

Plant species on these lists are also included on BICON, which outlines all import conditions for the importation of goods into Australia.

• Biosecurity Import Conditions system (BICON) 
• Wildlife trade and conservation: CITES and the Live Import List 

Physically stopping weeds entering Australia

The Department of Agriculture, Water and the Environment is Australia’s first line of defence in protecting our environment against exotic pests and diseases.

The Department of Agriculture, Water and the Environment and the Australian Border Force  inspect incoming luggage, cargo, mail, animals and plants and their products, and prevent prohibited plants and plant material from entering Australia. The Department of Agriculture and Water Resources also provides inspection and certification for a range of exports. These actions reduce accidental or unauthorised weed entry through baggage, cargo and mail.

Australia’s proximity to the South East Asian and Pacific regions places strategic quarantine importance on northern Australia. The Department of Agriculture, Water and Environment Northern Australia Quarantine Strategy  (NAQS) aims to protect Australia from exotic pests, weeds and diseases that could enter from countries to its north.

In agriculture, the pathways for spread include transported livestock and fodder, contaminated crop and pasture seeds, deliberate introductions of new species, and contaminated machinery such as harvesters and recreational vehicles (including boats which can spread water weeds).

There are many ways to prevent weeds in agricultural activities which are well known including:

Restricting the opportunity for new weeds to invade and spread:

• Be vigilant about introducing stock, fodder or seed onto your property to ensure weeds will not be introduced.
• When buying stock, find out where the stock has come from and what weeds infest that area.
  Buy certified weed free fodder and seed where possible.
• Restrict the movement of vehicles and machinery on your property in periods when seeds are likely to spread.
• Establish tracks and laneways along which vehicle movement can be concentrated.
• Wash down vehicles which have been in known infested areas.
• Do not allow machinery or vehicles to enter your property unless they are clean.

Restricting the spread of existing weed infestations:

• Carry out control works prior to other works.
• Slash and cultivate when weeds are outside of seeding period.
• Work the clean area first and the infested area last. Work from the outside in and clean down equipment prior to moving into a clean area.

Quarantine:

• Hold livestock that may be infested with seed in a single location until they are shorn or until weed seeds have had the chance to pass through their digestive system.
• Feed out infested fodder in a feed lot type situation only and introduce clean fodder to stock.

Monitor:

• Continually monitor weed infestations and carry out control works.

Plants from commercial nurseries, landscaping suppliers and gardening clubs can also be pathways for the introduction and spread of weeds. Another significant cause of weed spread is inappropriate use and disposal of garden waste.

There are a large number of potential weeds in Australian gardens. Private gardens contain over 4000 plant species with weed potential, while botanic gardens hold approximately 5000 species of plants with weed potential. The likelihood that any particular plant will become a weed is difficult to predict; however, the CSIRO has estimated that an average of 10 weed species establish in Australia each year.

Measures for weed prevention in your backyard include:

• Choose plants that are unlikely to become weeds in your area.
• Check existing garden plants are safe.
• Remove potentially weedy plants.
• Dispose of garden waste carefully.
• Be careful not to spread weeds.
• Place mulch on soil surfaces in the garden to reduce weeds growth.

Landscapes that contain a diversity of healthy, vigorous vegetation with very little bare ground have the ability, in most cases, to deter weed invasion. It is important to reduce the risk of the environment becoming vulnerable to invasion by exotic species by encouraging beneficial vegetation growth and by avoiding disturbance as much as possible.

Measures for weed prevention in the landscape include:

• Minimise the disturbance of desirable plants along trails, roads, and waterways.
• Maintain desired plant communities through good management.
• Monitor high-risk areas such as transportation corridors and bare ground.
• Revegetate disturbed sites with desired plants.