Untreated grapes (left) compared to grapes treated with Miravis® Prime (right) at the Hickman, CA, Grow More Experience site. (Photo taken 6/21/18.)

There are few agronomic challenges CA grape growers struggle with more than powdery mildew. The disease – whose powdery appearance on leaves and fruit gave it its name – is a fungus that most grape growers face each season.

At the Hickman, CA, Grow More^TM Experience site, we strategically chose to use chardonnay grapes in research trials because the variety is more prone to powdery mildew pressure than other varieties. That pressure is evident in this year’s trials, as the grapes in untreated areas appear dusty and have stunted growth.

Untreated grapes in Hickman. (Photo taken 6/21/18.)

The key to good control is using fungicides with multiple sites of action to avoid resistance. While growers continue to struggle to control the disease, new trials at the Hickman site show promising opportunities for growers in the coming years.

We anticipate registration of Aprovia Top® and Miravis® Prime fungicides for grapes in CA in the next few years. Aprovia Top will have a fit for early-season control of powdery mildew, while Miravis Prime will provide later season powdery mildew and botrytis control. Both fungicides are performing well in our trials at Hickman this year.

Grapes treated with Aprovia Top (top) and Miravis Prime (bottom) have uniform shape, bright green coloring and clear skins and leaves. (Photos taken 6/21/18 in Hickman.)

For more information about the powdery mildew trials in Hickman, contact your Syngenta representative.

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All photos are either the property of Syngenta or are used with permission.

Aprovia Top and Miravis Prime are not yet registered for sale or use in the United States and are not being offered for sale.

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