Amsinckia - Control Guide

Amsinckia, photo: Karen Stewart

Do's and Don'ts of Amsinckia control


  • Plan your control program, this will save time and money in the long-run;
  • Ensure cultivation, harvesting and road-grading machinery used in an infested area is washed down to remove any amsinckia seed;
  • Maintain a dense and vigorous pasture to prevent amsinckia establishing;
  • Take careful note of stock withholding periods after spraying to avoid stock eating the treated amsinckia;
  • Seek a vendor declaration to identify weeds which may be present in purchased feed and grain;
  • Use a dedicated feedout area to avoid spread of weeds that may come in purchased feed and grain.


  • Don't introduce amsinckia into amsinckia free areas (e.g. by failing to wash down machinery and equipment between sites);
  • Don't start your control program without first planning your approach;
  • Don't rely on slashing to remove amsinckia;
  • Don't expose stock to dense amsinckia infestations in case of poisoning.

Spread of Amsinckia

  • Amsinckia spreads by seed only. Seed is spread on farm equipment, in contaminated fodder and feed grain, and via sowing of contaminated seed. Seed can also be spread by contaminated bird seed.
  • Amsinckia can also be spread when the bristly flowers lodge in the coats of feral animals and stock, and when seed is carried in the digestive tracts of birds and stock.

Avoid the introduction of Amsinckia

  • Implements and vehicles which have been used on infested areas should be thoroughly cleaned before leaving the site.
  • Avoid using fodder and seed grain sourced from areas infested with amsinckia.
  • See the Washdown Guidelines for Weed and Disease Control for detailed information on how to wash-down equipment and personnel to reduce the chance of spreading amsinckia.

Physical removal

  • Small infestations of amsinckia can be removed by hand pulling.
  • For larger infestations on grazing land, mowing or slashing just before flowering can reduce seed production and if undertaken repeatedly will deplete the soil seedbank.


  • Amsinckia germinates over an extended period in the autumn and winter, making it very difficult to control by cultivation alone.
  • In cereal fallows, repeated cultivations will destroy amsinckia seedlings from early germinations, but follow up herbicide treatment is needed after crops are sown.
  • Repeated harrowing can be effective in controlling seedlings.
  • Competition from pasture legumes can be used to suppress amsinckia during the fallow phase on lands used for cereal growing.


  • Grazing of goats can be used to control amsinckia.

Chemical control

  • A number of herbicides are registered for use on amsinckia in Tasmania (see Herbicides for Amsinckia Control for more information).
  • Glyphosate products can be used for control in pasture or cropping situations prior to sowing.
  • Metsulfuron-methyl applied before crop is sown will give control from several germinations before and after crop.
  • Staggered seeding makes control in cropping situations challenging. For information relating to control in specific cropping situations contact an agronomist.

Important Disclaimer
    To the extent permitted by law, the Tasmanian Department of Primary Industries, Parks, Water and Environment (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using information or material (in part or in whole) contained on this website.

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