Fungicide Valbon (benthiavalicarb and mancozeb) has been granted a specific off-label approval (SOLA) by the Chemicals Regulation Directorate for use on table wine grapes.
The approval allows growers to take advantage of its activity against downy mildew, and is one that UAP agronomist Julian Searle describes as being very welcome.
Julian explains that downy mildew is a very serious disease in grapevines. "There are three diseases of concern for the crop – downy mildew, powdery mildew and botrytis and they all have the potential to destroy an entire crop," he warns.
"So we were very pleased to see the application for an off-label for Valbon – we’re very short of downy mildew treatments – critically so," explains Julian.
"And with the area of grapes grown in the UK increasing – from around 1,000 acres ten years ago to over 1,000 hectares now – a significant increase – it really is a timely and essential off-label that will get us out of a hole."
Julian warns that although our climate this year has given low pressure and primary infection so far, in certain areas of significant rainfall – particularly in the west where there’s substantial areas of vineyards – the threat of infection increases significantly.
"It’s a cost effective option which complements other solutions such as Aliette 80WG (fosetyl-aluminium) that’s also got an off-label approval for grapes and fits well as part of an anti-resistance strategy," says Julian.
He adds that Valbon’s chemistry is particularly useful for grapevine treatments with a relatively new benthiavalicarb component combined with mancozeb offering curative and protectant activity, along with retrospective kick-back activity.
Valbon has been successfully used in potato crops for the control of late blight as well as having an extension for use in ornamental and amenity vegetation against downy mildew.
The maximum individual dose for grapevines is 1.6kg /ha with a maximum two applications permitted per year. Growers must ensure a 56 day harvest interval is observed, but Julian believes this is of no significant disadvantage.
"Timing for use can occur through later flowering to early fruit set for 5 to 6 weeks," he advises. "Because of its crop safety it can be used over flowering – when the crop can be very susceptible to downy mildew."
As with any off-label approval growers are reminded that use is at growers’ own risk.
