The new registration of Miravis Prime fungicide in cherries helps address what has been a gap in available control measures for Botrytis cinerea, offering optimum protection against the disease.
Syngenta Technical Services Lead Dr Brandy Rawnsley said Botrytis cinerea presented a significant challenge with early infections sometimes not being detected until much later in the crop, presenting serious issues.
“Botrytis cinerea is a weak pathogen and can only infect through wounds or openings,” she said.
“The fungus typically infects ripe fruit, but it can often begin at flowering and lie inactive (latent) until symptoms develop later in the season.
“Botrytis infection can cause petals to wither and fall, which affects fruit set and results in poor yield.”
Dr Rawnsley said Miravis Prime contains two active ingredients; pydiflumetofen (Group 7) and fludioxonil (Group 12).
Pydiflumetofen moves rapidly into the waxy layer of the plant to provide long-lasting protection, whereas fludioxonil forms a protective barrier on the surface of the plant.
As a suspension concentrate, Miravis Prime has shown excellent crop safety when used in cherries for exceptional control of Botrytis grey mould.
“The best time to apply Miravis Prime is at beginning of flowering,” said Dr Rawnsley.
“The fungal species Botrytis cinerea occurs across a wide range of crops, so spores are prevalent in many horticultural areas. Protecting flowers stops disease development early in the season before it’s too late.”
Miravis Prime fungicide can also be used during the period prior to harvest to offer protection of the fruit during ripening, picking, transport and storage, giving growers the confidence they will produce premium quality fruit.
Rain can increase the risk of fruit cracking and grey mould around harvest, so the 3-day withholding period of Miravis Prime provides an ideal solution when growing for domestic and many key export destinations.
“Make sure you check the AusCherrySure app for specific export market Maximum Residue Limits (MRLs).”
A timely application of Miravis Prime at this time offers protection of the fruit during ripening, picking, transport and storage, giving growers the confidence they will produce premium quality fruit.
With most cherries grown in southern Australia, the registration of Miravis Prime was supported by independent trials conducted in Tasmania through the Hort Innovation cherry research and development levy fund (project ST20005).
In one trial, Miravis Prime fungicide was applied at two different label rates (60 mL and 100 mL/100 L) on cherries at the beginning of flowering and 11 days later.
Aborted fruit were collected from trees and assessed 63 days after the last spray and showed Miravis Prime provided exceptional control of Botrytis grey mould (Figure 1).
No disease was detected after treatment with Miravis Prime at 100 mL/100 L compared to 6 per cent of fruit infected after treatment with an industry standard.
These results highlight the benefit of using Miravis Prime at the highest label rate for optimum control of Botrytis grey mould. This study also assessed dilute versus concentrate applications and found when applied as a 3x concentrate spray, Miravis Prime provided effective control of the disease.
As with any fungicide use, a spray program should adhere to the CropLife Fungicide Resistance Management Strategy.
Although a specific strategy does not exist for Botrytis, there are other Group 7 fungicides that can be used for fruit rot caused by Monilinia species.
“It’s important to rotate chemical mode of action groups not only for resistance management purposes, but to change the way a fungal population is targeted.
“Group 7 fungicides work so well because they target a very specific region in the mitochondria. But because of this, they are considered medium - high risk of fungi developing resistance to them.”
Miravis Prime fungicide should be applied preventatively before disease occurs. A total of two Miravis Prime applications can be made to a cherry crop with no more than a total of three Group 7 fungicide applications in a season.
“And remember, the first spray of the coming season shouldn’t be a Group 7 if it was the last spray of the previous season - this is regarded as consecutive applications.”
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