Lucerne spraying

Winter weed spraying of Lucerne stands is essential to maintain longevity and maximise the production of high quality feed.

Lucerne does not tolerate competition from weeds, and I recommend the following weed management programme to optimise production.

  • Spray established Lucerne paddocks (stands two-years-old or more), with a combination of Gramoxone, plus a residual herbicide (Nutrazine 900DF or Simazine or Terb 500).
  • Apply when the Lucerne is dormant, usually from early June through to early August.
  • Prior to spraying, paddocks must be grazed firmly to remove excess Lucerne and weed foliage. The more bare soil showing, the better the residual control.
  • Allow 10 to 14 days to freshen after grazing prior to spraying, as dirty foliage will deactivate Gramoxone.
  • Fertiliser should ideally be applied at least 14 days prior to spraying, as later applications can affect weed control in the vehicle wheel marks.
  • Heavy rolling should also be done at least 14 days prior to spraying.

To obtain the best results from Gramoxone plus residual herbicide, also consider the following points:

  • Spray with clean water, as dirty or cloudy water will deactivate Gramoxone.
  • Water rates should be a minimum of 250 litres/ha (preferably 300 litres), as Gramoxone is a contact herbicide, with little translocation in the leaf. Lower water rates can show up as a spotting effect on the leaves, resulting in very poor weed control.
  • The addition of a non-ionic surfactant such as 'Spreadwet' will assist coverage and may also help to prevent runoff. Do not use a Penetrant such as 'Pulse'.
  • Do not pre-mix herbicides; add Nutrazine 900DF or Simazine or Terb 500 to the spray tank first, and then add the Gramoxone
  • Avoid grazing after spraying as long as possible, preferably until after the first cut of hay or silage. If grazing is necessary early on, wait until ground conditions are dry as any disturbance of the soil can lessen the residual control period.

Correct weed identification is important so the correct herbicide selection and rate or application can be made. Contact your local Farmlands technical field officer to inspect your Lucerne paddocks and to give you the correct chemical recommendation.

Always read the chemical label before spraying


Article provided by Roger Chambers - Farmlands technical field officer