Weeds

Weeds pose a serious risk for primary producers as they can impact on market access and agricultural production.

In 2006/07, each Western Australian agricultural business spent an average of $29 376 ($341 million total) on weed control (Australian Bureau of Statistics).

Weed control is a shared responsibility between landholders, grower groups, biosecurity groups and the Department of Primary Industries and Regional Development.

To protect WA’s agriculture, the department:

  • works with landholders, grower groups, community groups and biosecurity groups
  • regulates weeds under the Biosecurity and Agriculture Management Act 2007
  • provides a weed identification service
  • provides a predictive simulation tool called weed seed wizard
  • provides information on weed control, crop weeds, regulated/declared plants and herbicides
  • contributes to social science through weedwatcher.

For advice on weeds search our website, the Western Australian Organism List or contact our Pest and Disease Information Service (PaDIS).

For diagnostic services, please contact our Diagnostic Laboratory Services.

Articles

  • The term 'residual' applies to a number of herbicides that have a long lasting activity in the soil. These herbicides are often applied directly to the soil prior to planting crops, pre-emergent.

  • Herbicide performance can vary greatly depending on a number of factors. These can include compatibility of herbicides, water quality, sprayer decontamination and controlling stressed weeds.

  • Windmill grass (Chloris truncata) is a native species and is the tenth most common summer weed species in the Western Australian wheatbelt.

  • Annual ryegrass (Lolium rigidum) is one of the most serious and costly weeds of annual winter cropping systems in southern Australia.

  • Brome grasses (Bromus spp.) are highly competitive weeds, most problematic in wheat crops.

  • ‘Risk-aware’ growers can implement strategies to reduce and avoid unnecessary introduction and spread of weeds.

  • The Weed Seed Wizard is a computer simulation tool that uses paddock management information to predict weed emergence and crop losses.

  • In 2021 the Department is conducting over 300 research trials across the state from Kununurra in the north to Esperance in the south.

  • The most accurate way to estimate the weed population of a paddock is to count the number of plants in an area of known size at a number of locations.

  • In Western Australia, competition from 7-90 capeweed plants per square metre in a wheat crop can reduce crop yield by 28-44% and net return by 25-76%.

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