Overwatch Herbicide

PIC - Overwatch.jpg

Overwatch from FMC is the latest pre-emergent residual herbicide to be registered in Australia and will be available for the 2021 winter cropping season.

Overwatch contains the active ingredient Bixlozone which is a Group Q mode of action, at 400g/L. It will be registered for use in wheat, barley and canola. Overwatch will be the first group Q product to be registered in these crops, providing another tool to manage herbicide resistance.

The overwatch label claims:

  • Control of:

    • Ryegrass

    • Wireweed

    • Sowthistle

    • Bifora

    • Lesser loosestrife

    • Silvergrass

  • Suppression of:

    • Barley grass

    • Brome grass

    • Capeweed

    • Wild oats

    • Wild radish

    • Prickly lettuce

    • Annual phalaris

    • Bedstraw

Other characteristics of Overwatch include:

  • Single application rate of 1.25 L/ha

  • Must be applied IBS with knife point and presswheel sowing systems

  • It is non-volatile, however incorporation is still required within 3 days

  • Overwatch is a bleaching herbicide which can cause transient crop yellowing, this can be exacerbated when the crop is stressed from other factors. Wheat is the safest crop while barley is the most susceptible to damage.

  • It is taken up via plant roots so best results are achieved when weed seeds are on the soil surface. Therefore cultivation is not recommended prior to application

  • Requires rain to wash the herbicide into the root zone

  • Crop stubble and weed residues will reduce the amount of herbicide contacting the soil surface. Application to burnt paddocks should be delayed until the ash has dissipated.

  • Wheat seeds should be sown at least 30mm below the herbicide band to reduce crop affect

  • The label indicates an11 month re-cropping interval for chickpeas, faba beans and field peas

  • There is a 12 week grazing withhold period

  • Price is expected to be $38/ha

Work is currently underway to determine the safety of Overwatch on other crop and pasture species, with indications that it may be registered for numerous pulse crops, plus prior to sowing lucerne and subterranean clover in the future. This will be very useful to control both ryegrass and broadleaf weeds, which can be very challenging to control in these broadleaf crops.

Trials have also been conducted using disc seeders, with the potential for a registration in wheat possible.

CroppingFred Broughton