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Increased downy mildew pressure in vineyards

Downy mildew impacting vineyards and wine makers throughout New Zealand

Increased downy mildew pressure in vineyards

Viticulturists can expect increased downy mildew pressure this coming season and in years to come, due to the widespread and severe outbreaks of this disease which occur during periods of wet weather.

La Nina weather patterns in recent years have made it challenging to prevent these downy mildew outbreaks, says Paul Hassan, Syngenta Technical Services Lead. 

“Now, vineyard soils have increased downy mildew spore loadings, increasing the threat of further infections. Our recommendations for the season ahead are to utilise predictive weather forecasting tools to determine when downy mildew protectants need to be applied, and build out your programme with effective, rainfast options such as Ridomil® Gold MZ and Amistar®.”

Both products can be used preventatively. “Note that Amistar has no kick-back activity, so must be used prior to rain to protect new growth through its systemic, translaminar, and anti-sporulant activity,” says Paul. “But Ridomil Gold MZ is more flexible, and can be used both before and after a rain event which is helpful, especially in large vineyard situations where it can take several days to cover many hectares of grapes needing protective sprays.”

Ideally Ridomil Gold MZ applications are done prior to a predicted wet event, but if the spray round is interrupted by weather, it can also be applied after the rain to complete the spray round. “We recommend this post-rainfall application is done as soon as conditions allow and no later than five days after the rain starting.”

Make no more than one application of Amistar per season during the period from early flowering to 14 days pre-harvest. Make no more than two, non-consecutive applications of Ridomil Gold MZ per season.

Your local Fruitfed Supplies Representative can assist with more information about Amistar and Ridomil Gold MZ for your downy mildew protection programme.

ACVM registration numbers: Amistar® #P004840, Ridomil® Gold MZ WG #P005658. Read registered label before use.