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Pre-Emergent Herbicide Use in Southern NSW

Resistance to post-emergent herbicides has resulted in an increased reliance on pre-emergent herbicides, particularly products like Sakura and Boxer Gold.  Achieving the best results from these products requires an understanding of how the products work, label requirements and use restrictions.

Following are guidelines for the use of Trifluralin, Sakura, Boxer Gold, Avadex Xtra and Rustler:

Trifluralin

  • Volatilises (becomes a gas) if left exposed on the soil surface
  • Binds well to soil particles once incorporated
  • Binds tightly to stubble and trash
  • Absorbed primarily through plant roots

Best results are achieved:

  • When applied to bare soil
  • When incorporated within 4 hours
  • Using high water rates and large droplets when stubble is present
  • When applied separately to Glyphosate

Crop damage is minimised through:

  •  Sowing good quality seed
  • Ensuring seed is sown below the layer of soil treated with chemical
  • Minimising soil throw into adjacent rows, when using a knife point presswheel seeding system

Sakura

  • Can be applied up to 3 days prior to incorporation
  • Does not bind well to soil, so can wash into furrows easily resulting in crop damage
  • Doesn’t bind to stubble as tightly as Trifluralin
  • Taken up through the roots of the germinating plant

Best results are achieved:

  • When applied to bare soil
  • When sufficient rainfall occurs after sowing to wash the herbicide into the root zone of germinating weeds
  • When thorough incorporation is achieved

Crop damage is minimised through:

  • Sowing good quality seed
  • Ensuring seed is sown well below the layer of soil treated with chemical
  • Minimising soil throw into adjacent rows, when using knife points and presswheels
  • Not using a combination of presswheels and harrows
  • Not sowing into water logged soils
  • Not sowing if heavy rain is forecast soon after application and sowing

Boxer Gold

  • Can be applied up to 7 days prior to incorporation
  • Does not bind well to soil, so can wash into furrows easily resulting in significant crop damage
  • Doesn’t bind to stubble as tightly as Trifluralin
  • Taken up through the roots and coleoptile of the germinating plant
  • Foliar uptake is possible, so under ideal conditions seedling weeds may be controlled

Best results are achieved:

  • When applied to bare soil
  • When sufficient rainfall occurs within 10 days of application to wet the top 3-4 cm of soil
  • When thorough incorporation is achieved

Crop damage is minimised through:

  • Sowing good quality seed
  • Ensuring seed is sown well below the layer of soil treated with chemical
  • Minimising soil throw into adjacent rows, when using knife points and presswheels
  • Split application IBS and PSPE
  • Not sowing into water logged soils
  • Not sowing if heavy rain is forecast soon after application and sowing

Avadex Xtra

  • Should be incorporated within 6 hours when applied to moist soil, or 24 hours if applied to dry soil
  • Taken up through the coleoptile of the germinating plant
  • Requires thorough incorporation
  • Requires moisture to be activated

Best results are achieved:

  • When applied to bare soil
  • When thoroughly incorporated in the top 3-4 cm of soil
  • When rainfall occurs soon after sowing to activate the chemical

Crop damage is minimised through:

  • Sowing good quality seed
  • Ensuring seed is sown below the layer of soil treated with chemical
  • Minimising soil throw into adjacent rows, when using a knife point presswheel seeding system

Rustler

  • Is not volatile, so does not require immediate incorporation
  • Does not bind as tightly to soil particles, stubble and trash as Trifluralin
  • Is relatively insoluble. Even in moist soil it tends to move less than 5 cm down the soil profile
  • Absorbed primarily through plant roots
  • Does not work well in dry conditions

Best results are achieved:

  • When applied to bare soil
  • When applied in cool moist conditions
  • Where weed seeds are in the top 1cm of soil
  • When rainfall of 25-50mm falls soon after application
  • Using high water rates and large droplets when stubble is present

Crop damage is minimised through:

  • Sowing good quality seed
  • Ensuring seed is sown below the layer of soil treated with chemical
  • Minimising soil throw into adjacent rows, when using a knife point presswheel seeding system.