grass roots community organisation that aims to improve natural condition of the derwent catchment

Whiteweed

Disclaimer

The following page is a brief summary of information available on the DPIPWE website regarding Whiteweed control. For more information view here

Non-chemical control

Cultivation

  • When infested pastures are cultivated for resowing to pasture or for cropping, Whiteweed numbers may increase dramatically. This results from both the fragmentation of the root system during cultivation and the removal of grazing pressure.
  • Cultivation alone will not provide long-term control of Whiteweed. Continuous cultivation will kill Whiteweed roots in the topsoil, however new shoots can continue to emerge from roots below the depth of cultivation.

Grazing

  • Whiteweed is readily grazed by sheep and may not be noticed in heavily grazed sheep pastures. However, grazing only removes the shoots of the plant and Whiteweed will persist even under very heavy grazing.
  • Cattle and horses usually avoid grazing on Whiteweed.
  • If a landholder resows to pasture or commences cropping in infested paddocks without being aware that Whiteweed is present (due to heavy grazing by sheep), Whiteweed may appear in large numbers from regeneration from root fragments.
  • Whiteweed may taint the meat of grazing stock, and sheep should not be used for control of the weed immediately before being sent for slaughter.

Chemical control

Use herbicides in accordance with label. Refer to APVMA permit PER13160 where herbicide is to be used in non-cropping and bushland areas

Application method

1. Spot spraying

  • Stage of growth - actively growing to mature
  • Location - Non-cropping and bushland
  • Suggested herbicide - Weedmaster® Duo, Roundup Biactive®

Integrated management

Control in permanent pasture

  • Heavy grazing by sheep is the best method of controlling Whiteweed in permanent pasture. Stock that have grazed mature Whiteweed plants can spread seed to clean areas, so grazing should be timed to avoid seed production.
  • Where sheep grazing is not possible, slashing of the flowering and seeding stems in spring may be used to reduce competition and to open up the infested area for grazing by cattle or horses. However, slashing will have little long-term effect on the Whiteweed infestation, even if seed production is totally prevented.

Control in cropping systems

  • In pasture or fallow, treat Whiteweed with herbicide at the bud stage in spring prior to cropping. Where crop sowing is to be undertaken immediately after herbicide application, glyphosate or glyphosate/dicamba mixtures can be used. Where suitable crops (cereals or forage grasses) are to be sown in the following autumn, the herbicide chlorsulfuron can be used. Consult an agronomist. Where herbicides are used adhere to product labels.
  • Where crops other than cereals or forage grasses are to be sown, no further herbicide treatment is available. Wherever possible, a cereal or grass crop should be sown as the initial crop in such areas. These crops can be treated with chlorsulfuron as above.
  • Where the Whiteweed infestation is very dense, a cereal cropping program may need to be undertaken for two seasons to gain control of the weed.
    After one or more seasons of non-cereal cropping, the Whiteweed may again increase to significant levels. In such situations, rotation back to a cereal crop and in-crop treatment with chlorsulfuron may be necessary to reduce the infestation.