New fungicide delivers "game-changer" disease control to vegetable growers in Australia

Growers will this year welcome a new fungicide offering outstanding protection against key diseases in root and fruiting vegetables, cucurbits, celery and peanuts.

Syngenta has worked closely with the Australian Pesticides and Veterinary Medicines Authority (APVMA), to compile data from comprehensive trials for the anticipated registration of MIRAVIS^® Duo* fungicide.

"This is an exciting new development in the MIRAVIS^® brand family," said Syngenta Technical Services Lead, Dr Brandy Rawnsley.

Syngenta Technical Services Lead Dr Brandy Rawnsley (pictured) says trials of MIRAVIS® Duo fungicide have been outstanding, with no to very little disease observed on treated plants.

"The active ingredient pydiflumetofen was introduced in Australia in 2018 and has been a game changer for control of powdery mildew in grapes and target spot (Alternaria) in potatoes. This same active will now be introduced to preventatively control key diseases across a broad range of vegetable crops."

MIRAVIS^® Duo fungicide combines pydiflumetofen (group 7) and difenoconazole (group 3) in a formulation that will provide best-in-class disease control, while mitigating the risk of fungicide resistance.

"Pydiflumetofen protects the plant from fungal pathogens by targeting fungi at four different stages of the lifecycle, and with proven activity of difenoconazole, MIRAVIS^® Duo fungicide provides an optimised formulation for best-in-class protection," said Dr Rawnsley.

Figure 1. Incidence and severity of Alternaria and powdery mildew in processing tomatoes assessed 28/2/2022, 21 days after the last application of MIRAVIS Duo applied at 1 L/ha and AMISTAR Top at 500 mL/ha at 14-day intervals, water volume 325 L/ha, NSW (2022).

"Upon application, MIRAVIS^® Duo fungicide is locked in the leaves, building up a reservoir to stop fungal pathogens entering the plant. Preventative use prior to infection achieves optimal protection of your crop, especially when wet, humid conditions prevail."

In fruiting vegetables, such as tomatoes, MIRAVIS^® Duo fungicide targets powdery mildew, target spot and Cercospora leaf spot. Registration is expected in both open field and protected cropping situations.

"Trials have been outstanding, with no to very little disease observed on treated plants," said Dr Rawnsley.

A recent trial held in conjunction with Kagome, Australia's largest processor of tomatoes, highlighted two applications of MIRAVIS^® Duo fungicide provided exceptional preventative disease control in the season (Figure 1). Additionally, the crop was more vigorous and showed improved greenness (Figure 2).

With an anticipated 1-day withholding period upon registration, Dr Rawnsley said MIRAVIS® Duo fungicide would offer excellent protection of fruit and peace of mind at harvest.

For cucurbit growers, Dr Rawnsley said MIRAVIS^® Duo fungicide would become the gold standard in fungicide programs, when used preventatively.

At the Syngenta GrowMore demonstration site held in Bowen, Qld in 2021, MIRAVIS^® Duo fungicide was used in rotation with ORONDIS^® Flexi fungicide (downy mildew, powdery mildew and gummy stem blight protection in cucurbits) as part of a program that was subjected to very high disease pressure.

EE Muirs Sales Agronomist Tom Andison works across the Burdekin in North Queensland and took a keen interest in the Syngenta GrowMore Bowen site.

Mr Andison said the treated crop area showed no sign of disease even though it was adjoined an untreated area that had high disease pressure.

"Considering the way the site was set up, and how the prevailing wind was blowing from the untreated to the treated, the difference MIRAVIS^® Duo made to how clean the crop was... it's huge," he said.

Mr Andison said the site had demonstrated the fungicide's preventative activity on powdery mildew and other key cucurbit diseases.

"I was pretty impressed with the way that [MIRAVIS^® Duo] kept the powdery out of the rockmelons," he said.

"It's got the dual actives and it attacks the powdery on multiple levels. So it gives you confidence that when you put it on before the pressure arrives, it's going to do its job."

Agronomist Tom Andison says the GrowMore site had demonstrated the effectiveness of MIRAVIS® Duo fungicide against key cucurbit diseases.

While strong on powdery mildew, Dr Rawnsley said MIRAVIS^® Duo fungicide had a broad label for disease protections that regularly worry growers.

"MIRAVIS^® Duo fungicide is a great option for cucurbit crops as it not only protects against powdery mildew, but also gummy stem blight, Alternaria and Cercospora leaf spot," she said.

"I gave agronomists a task to find disease symptoms in the treated crop at Bowen, but they were amazed to find no disease when it was so severe in the untreated area."

Likewise, use of MIRAVIS^® Duo fungicide in a watermelon crop in South Australia inhibited powdery mildew and Alternaria infection, resulting in a healthy crop with large fruit, Dr Rawnsley said.

"The one-day withholding period means growers can use it with confidence without affecting decisions of best harvest time," she said.

MIRAVIS^® Duo fungicide is a suspension concentrate (SC), and has been tested to be highly compatible with a range of other crop protection products, such as insecticides and foliar nutrients. It also has a built-in adjuvant, so an additional wetter does not need to be added to the tank.

With excellent crop safety and efficacy in fruiting vegetables and cucurbits in both open field and protected cropping, MIRAVIS^® Duo fungicide offers the flexibility to be used by a wide range of growers in northern and southern horticultural regions.

In root vegetables (e.g. carrots, beetroot), MIRAVIS^® Duo fungicide provides protection of early blight (Alternaria spp.) and powdery mildew. Both foliar diseases can cause weak, dry leaves resulting in un-harvestable crops.

"Applications of MIRAVIS^® Duo fungicide have been shown to enhance green leaf area and vigour, meaning good growth for tuber and root development. Applications should be implemented just prior to row closure to protect the canopy, then again at root bulking meaning the seven-day withholding period is favourable," Dr Rawnsley said.

With limited fungicide options available in celery, it will also be a welcome registration by growers to control Septoria and Cercospora leaf spots. Both diseases can devastate the quality of celery, especially when wet conditions prevail.

"MIRAVIS^® Duo fungicide, where used preventatively before a rain event, gives lasting protection when it matters most," Dr Rawnsley said.

"In peanuts, MIRAVIS^® Duo fungicide will provide up to 28 days protection against early leaf spot, late leaf spot, net blotch and suppression of rust. The long spray re-application interval of 21 to 28 days will be a game-changer for peanut producers, with efficiencies of time, labour, resources, and crop health."

Figure 2. MIRAVIS® Duo fungicide treated processing tomato crop (right) compared to the untreated (left).

Dr Rawnsley said peanut trials showed areas sprayed with MIRAVIS^® Duo fungicide at the proposed label rate of 600 mL/ha were greener and more vigorous, resulting in greater biomass compared to the surrounding crop.

"The strip sprayed with MIRAVIS^® Duo fungicide stood out in the paddock", said Neil Bauer, Syngenta Senior Sales Executive, Qld. "It really gave us confidence that we didn't need to spray for 28 days and the 14 days withholding period saw it through to desiccation."

MIRAVIS^® Duo fungicide will be restricted to two applications per crop per year to minimise development of resistance to fungicides and provide long-lasting solutions for future generations.

^® Registered trademark of a Syngenta Group Company. *MIRAVIS Duo is not registered. An application has been submitted to the APVMA.