Trials on UK grape vines have shown that applying silicon as a foliar spray can help reduce excessive accumulation of copper, which can affect the sensory qualities of wine. Trials carried out by Orion FT showed that applying a silicon-based biostimulant strengthens the plant’s natural defences to mildew infection and can help it resist aphid and caterpillar feeding damage.

“Our trials showed an increase in silicon uptake of 30% following the application of Fossil, a silicon biostimulant, as a foliar spray. The product also helped the vines to take in significantly more zinc and iron, both essential for the formation of sugars. Optimising nutrient levels is a key property of biostimulant products,” explains technical specialist Kate Williams.

Elevated levels of copper in the soil can cause reductions in the levels of beneficial bacteria and fungi in the rhizosphere. Therefore, reducing the reliance on these products and filling the gap with a silicon biostimulant can both improve soil health and strengthen the plant naturally.

“We are not advocating that growers stop using fungicides. However, our trials show that by including a silicon biostimulant as part of an IPM approach, vines will carry less copper and more micronutrients, which will improve plant health, yield and also improve the aromatics of the wine,” she adds.

The prevalence of excess copper in grape juices can have an adverse effect on the thiols of some wines, negatively affecting the aroma. A silicon biostimulant can be mixed with a fungicide to offset this whilst also strengthening the plant.

“Our findings provide evidence for the potential of at least partially replacing conventional fungicides. By protecting soil and biodiversity it also has the potential to make viticulture more sustainable. Silicon applications are a relatively low-cost option, can be added to a tank with other products, and have the added advantage of complying with the principles of the Sustainable Use Regulations,” she concludes.