Herbicides are chemicals that destroy or inhibit the growth of plants.  They play a vital role in an Integrated Pest Management plan. Numerous herbicides are registered with the Australian Pesticides and Veterinary Medicines Authority for use in Western Australia (WA).

In 2006–07, 91.4% of Western Australian agricultural businesses used herbicides to control weeds. Total expenditure for all types of weed control was $341 million (Australian Bureau of Statistics).

Weed control is a shared responsibility between landholders, grower groups, biosecurity groups and the Department of Agriculture and Food, Western Australia (DAFWA). To protect WA’s agriculture, DAFWA:

  • works with landholders, grower groups, community groups and biosecurity groups
  • provides information on using herbicides, herbicide resistance and herbicides that can be used on declared plants in WA.

If you need advice on herbicides please search our website or the Australian Pesticides and Veterinary Medicines Authority website. Our Pest and Disease Information Service (PaDIS) can also put you in contact with a herbicide expert.


  • Summer weeds can rob subsequent crops of soil nitrogen and stored soil water. They can also reduce crop emergence by causing physical and/or chemical interference at seeding time.

  • Control methods for apple of Sodom (Solanum linnaeanum) a declared pest in Western Australia.

  • Herbicides can be applied by a variety of means including boom sprayers, aerial spraying, misters, blanket wipers, rope wick applicators, weed seekers and back-pack sprayers.

  • Options for control of winter broad leaved weeds, in pastures, is a common inquiry. A fairly reliable method is spray grazing.

  • Doublegee or spiny emex is a significant weed in Western Australia. It is a vigorous annual herb with a strong tap root and a long, fleshy, hairless stem.

  • Herbicide resistance is the inherited ability of an individual plant to survive a herbicide application that would kill a normal population of the same species.

  • In Western Australia, rising temperatures and falling water levels over summer encourage algae and aquatic weed growth in farm dams.

  • Control methods for African rue (Peganum harmala) a declared pest in Western Australia.

  • Control methods for blackberry (Rubus species), declared pests in Western Australia.

  • Control methods for alligator weed (Alternanthera philoxeroides) - a declared pest in Western Australia.