Revolutionary Herbicide Overwatch Now Available For Australian Market

From FMC Australiasia Pty Ltd

Overwatch® Herbicide from Agricultural Sciences Company FMC, has officially been registered and will be available for the 2021 winter cropping season as a control for annual ryegrass and a wide range of other weeds.

FMC Herbicide Portfolio Manager, Hugh Palmer, said Overwatch Herbicide, powered by Isoflex™ active, has been extensively trialled over many seasons and will be available as a pre-emergent option in wheat, barley and canola.

“This is a really unique herbicide,” he said, Overwatch controls Annual ryegrass and weeds such as silvergrass, bifora, sowthistle, hogweed and lesser loosestrife.”

Mr Palmer said the innovative pre-emergent herbicide was initially assessed as an annual ryegrass product because of the concern regarding that weed in winter cropping regions throughout Australia. “It has outstanding annual ryegrass control and the fact that it effectively controls a wide range of other species is a real bonus.”

Mr Palmer continued, “there are a large number of weeds registered for suppression on the label, so this herbicide will have an excellent fit in many paddocks.”

Overwatch® Herbicide also has long-lasting residual control making it very effective on later germinating weeds. Up to 12 weeks control of a wide range of species has been demonstrated.

Its active ingredient bixlozone, trademarked Isoflex™ active, is proposed as a Group Q molecule, making it unique in the Australian broadacre market.

“Registration is very timely, as many of the weed species are developing resistance to commonly used herbicides.” Said Mr Palmer. The use of Overwatch® Herbicide in a winter crop system will help take the pressure off herbicides that are struggling with resistance. Overwatch® also has the ability to control weeds that are no longer susceptible to other options.”

Mr Palmer said the herbicide’s unique mode of action certainly had growers and agronomists taking note as the ryegrass germinated and turned a bright magenta colour before perishing.

“Overwatch® Herbicide works by inhibiting the production of carotenoids in susceptible plants,” he said. 

“This, in turn, affects a plant’s ability to produce energy through normal photosynthetic pathways. While the crop is able to metabolise the herbicide, the susceptible weeds use up available energy from the seed and then die.”

Overwatch® Herbicide is applied as an IBS (Incorporated By Sowing) treatment and has demonstrated its robust performance across a wide range of locations and conditions.

“Trials have been conducted across all the major winter crop areas of Australia and have included testing in a wide range of soil types, stubble loads and moisture conditions,” Mr Palmer said.

“The efficacy of Overwatch® Herbicide has been outstanding across the different environments. It has consistently demonstrated really good control of weeds.”

Because Overwatch® Herbicide is registered in three key winter crops, it provides greater options for crop rotations.

“Residual herbicides have been challenged with dry conditions in recent years so the introduction of Overwatch® Herbicide means growers can have more flexibility with regard to following crop.”

Crop safety was an important aspect of achieving registration, and many trials have been conducted to demonstrate the ability of the crops to metabolise the herbicide and continue to grow.

“Some pre-emergent herbicides affect cell division and that may limit the crop’s root or plant growth,” Mr Palmer said. The effect is not seen in Overwatch® Herbicide and the only sign of the herbicide being metabolised is a transient discoloration of the crop.”

“Discolouration is common and is usually associated with higher doses of herbicide contacting the seed or plant directly. In the case of Overwatch® Herbicide symptoms become negligible within weeks of the first appearance and the plants continue to actively grow throughout the process.” said Mr Palmer.

The recommended application of Overwatch® Herbicide via Incorporated By Sowing (IBS) helps to ensure the seed is placed sufficiently away from the herbicide.

Mr Palmer said, “there will be many trial sites throughout Australia in 2020 available for inspection by growers and agronomists, I would encourage interested parties to have a look at the performance of this unique herbicide and see how suitable it is to current farming practices.”

FMC Herbicide Portfolio Manager, Hugh Palmer addressing agronomists at an Overwatch® Herbicide field day at Temora, NSW.