Syngenta Australia Victrato product lead Katie Slade.

AUSTRALIAN wheat and barley growers have at their disposal a new technology to counter crown rot following the approval of Syngenta’s Victrato seed treatment.

Its patented Tymirium technology has cyclobutrifluram as its only active constituent, and it was last month approved by the Australian Pesticides and Veterinary Medicines Authority for use on both cereals.

Under APVMA requirements, and in line with some other seed treatments, seed treated with Victrato cannot be used for animal or human consumption, and crops grown from treated seed cannot be grazed or cut for fodder for six weeks after application.

However, there is no withholding period on harvested grain.

Syngenta’s Grower Process document outlines the need for growers to secure a unique reference number in order to minimise the chances of a build-up in cereal resistance to Victrato, and also to ensure its use does not impact livestock production.

Long road to approval

Victrato has been under development in Australian for five years, and Syngenta has conducted more than 300 trials around it nationally, making it the company’s biggest program to date.

Cyclobutrifluram has in recent years become available in certain jurisdictions around the world as a nematicide for use in horticulture and turf.

Australia is believed to be the first country in which it has been formulated and approved for use in broadacre farming as a counter to crown rot.

Crown rot is caused by fusarium species inoculum, which survives in the stubble of previous crops.

Seed treated with Victrato interrupts activity of mitochondria, and protects seedlings from infection as they emerge.

In contrast, mycelium can colonise plants grown from untreated seed, and movement of water and nutrients to wheat and barley heads can be restricted.

At maturity, crown rot can cause basal browning of stems, and whiteheads, which indicate unfilled or pinched grain, which can halve yield potential, or cause downgrading due to increased screenings.

Syngenta Australia Victrato product lead Katie Slade said few crop-protection products before it had represented such a significant development for the industry.

“Rarely as an industry do we have the opportunity to help growers drastically change the outlook for their crops on a scale like this,” Ms Slade said.

Potential fillip for durum

Ms Slade said this was especially the case for growers who had dropped durum from their rotations due to its susceptibility to crown rot.

“There are many agronomists – too many to name here – to whom we are grateful for their support in our journey with Victrato seed treatment,” Ms Slade said.

“We are just as excited as them to see the first batches of seed being commercially treated with Victrato, now that we can begin releasing supply.”

Provided durum has enough of a premium over bread wheat, AMPS agronomist Tony Lockrey said Victrato could well see durum reintroduced to some rotations.

“Anywhere that crown rot’s a big issue, it’s not going to add yield, but…it will recover yield,” Mr Lockrey said.

“It might recover 10pc in barley, 10-20pc in bread wheat, and 20-40pc in durum.”

Durum has fewer herbicide options than bread wheat, and at roughly $345 per tonne, or only $20/t above bread wheat, Mr Lockrey said it was unlikely to jump out at growers as a hot option for 2025-26, even with Victrato available.

However, this could change if the premium rises significantly, and growers are looking for an alternative to barley and bread wheat to grow after a pulse or canola.

“It opens the possibility for durum to be the first cereal after the rotation crop,” Mr Lockrey said.

AGT variety support manager north Douglas Lush said Victrato was likely to be an add-on to existing seed treatments which protect against bunts, smuts, and insects.

He said while Victrato’s trial results look promising, the difference it makes to growers’ bottom lines remains to be seen over commercial areas.

“It will probably bring in more paddocks to be seen as potentially suitable for durum,” Mr Lush said.

“If you have clean paddocks, then durum will be quite happy, whereas in a paddock with crown rot, what you’re doing is shifting your paddock to be like a clean paddock.”

Mr Lush said Victrato could also be useful for bread wheats susceptible to crown rot.

“Good farmers will use Victrato to good benefit, but it won’t paper over problems with rotations.”

Welcome in south too

In South Australia, AW Vater & Co last month let its clients know Victrato was coming.

AW Vater & Co agronomist Sam Modra said crown rot was also an issue in some paddocks in SA, where most durum is grown on contract to pasta manufacturer San Remo.

“We see a fair bit of crown rot, and would avoid putting durum into paddocks where we found it with Predicta B tests,” Mr Modra said.

“With Victrato, it’s definitely going to be a help for durum, and for some bread wheat on the Adelaide Plains.

“Guys growing durum would have more confidence about growing durum following beans, lentils and canola if they are testing and finding crown rot is there.”

In its communique to growers dated February 19, AW Vater advised that Syngenta required growers to obtain a unique reference number ahead of purchasing Victrato.

“They reason that good stewardship is vital to upholding standards, such as integrated management practices and safe handling and application, to avoid the development of resistance,” the AW Vater website said.

“Prior to purchase, growers will need to demonstrate ‘that they understand the product label and its requirements by completing a quick online stewardship program through myNGR.

Syngenta implemented a similar system for Reflex, a residual herbicide for pulse and vetch crops.

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