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.