Australia
November 1, 2023
Michelmore Farms at Langhorne Creek, South Australia grow approximately 250 hectares of crisping potatoes. Increasing organic matter levels in their sandy soil is a priority and so potatoes are grown in rotation with carrots, wheat, canola, triticale and vetch or beans as green or brown manure crops.
Potatoes are planted from July to March each year, with autumn often the worst time for one of their major potato diseases – target spot. Owner of Michelmore Farms, Steve Michelmore applies MIRAVIS® fungicide with his boom spray for control of target spot and found it a game changer. After talking to Dr Brandy Rawnsley, Syngenta Technical Services Lead, Mr Michelmore learnt about the registration of MIRAVIS® Duo fungicide for chemigation application in potatoes.
Syngenta Technical Services Lead, Dr Brandy Rawnsley, speaking to growers at a Syngenta Potato Partner field walk in Tasmania.
“I talk to Brandy a lot – she started my thought process about using MIRAVIS® Duo through chemigation,” said Mr Michelmore.
“Because Brandy had actually done trials herself comparing boom spray and chemigation application of MIRAVIS® Duo I took more notice than if I’d just seen it on a graph or in a pamphlet somewhere.”
MIRAVIS® Duo is the only potato fungicide registered for chemigation application in Australia. Mr Michelmore started chemigating with MIRAVIS® Duo for target spot last season and said it was a bit of a trial, but he was pleased with how well it worked.
“I used MIRAVIS® Duo in my very big canopy potato crops. I didn’t need to put the boom spray in the crop for anything else but was already fertigating, so it fitted in well,” said Mr Michelmore.
“It meant we weren’t bashing down a big canopy for just one fungicide boom application.”
“I didn’t do any organised trials, but by eye and by gut [feeling], the target spot control with chemigation was as good as using MIRAVIS® Duo with the boom spray.”
“The more times you run over the crop with the boom spray the more damage you do and the more points of entry for disease.”
“In a half a pivot you might have 20 spray runs and you’re losing yield every time you run over the crop.”
Mr Michelmore used the high label rate of MIRAVIS® Duo and applied it with trace elements and biological growth stimulants.
“We do a lot of fertigating, and we’ve got good dosing equipment so found it easy to use MIRAVIS® Duo through our system,” said Mr Michelmore.
“We made sure the agitation system was working really well, we actually upgraded that, which was cheap and easy and that has actually improved the application of other products as well.”
With Lake Alexandrina on one side as well as the Southern Ocean to deal with, it can be almost impossible for Michelmore Farms to apply fungicides on a single ideal spray day. When spraying opportunities are scarce, applying MIRAVIS® Duo fungicide via chemigation can free up the boom spray to be in another paddock at the same time.
“In certain situations, chemigating with MIRAVIS® Duo is actually easier and more cost-effective than using the boom spray. For us, that means when we’ve got big canopies and favourable target spot conditions and we’re trying to get an application on before disease becomes a problem, using chemigation is ideal,” said Mr Michelmore.
Dr Rawnsley explained that the difenoconazole component in MIRAVIS® Duo makes it well suited to preventative use later in a fungicide program.
“Pydifluemtofen acts primarily on fungal spore germination and germ tube elongation whereas the difenoconazole component in MIRAVIS® Duo acts on later stages in the fungal life cycle,” said Dr Rawnsley.
“This makes MIRAVIS® Duo ideally suited to later in a spray program for preventing disease development in those larger canopies.”
Mr Michelmore said MIRAVIS® Duo definitely has a fit in his integrated pest and disease management program in future seasons.
“MIRAVIS® Duo has a different fit in our program than MIRAVIS®. It’s good to have the two actives in MIRAVIS® Duo, it means it works well in fungicide rotations and we know we’ve got that different type of activity later in the season,” said Mr Michelmore.
“Chemigating with MIRAVIS® Duo gives us another really good tool and those big canopy crops is really where it fits for us.”
For more information, please contact your local Syngenta representative or visit www.syngenta.com.au/potatoes
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