Strong winds hinder potato blight programmes

Potato blight programmes are being severely disrupted by strong winds preventing spray applications.

With blight risk rising sharply in showery conditions, growers have the best chance of ensuring crops remain protected by using Revus when opportunities arise, advocates Tom Whitworth of Syngenta.

He warns the Syngenta BlightCast system has predicted high risk conditions with Full Smith periods over the Bank Holiday weekend across the South West and rising risk through South Wales and into the midlands. The threat for growers is being compounded by difficult spraying conditions. The Syngenta website's Spray Window Forecast for the South West, for example, indicates a potential to spray on Friday, but nothing further except a two-hour slot early on Monday morning. "If growers miss the chance, crops could be left exposed to any blight infection,"advised Mr Whitworth.

"Under such conditions the exceptional rainfast properties of Revus are essential to make the most of any break in the weather, when other fungicides could be washed off and efficacy reduced at a time when it's most needed."He added that Revus is very easy to use and, with the foil-free, fast-rinsing Syngenta S-pac, can maximise sprayer output whenever there's the chance to go.

Shropshire grower Mark Wilcox has some 375 hectares of crop in the ground this season, virtually all under contract for processing.  Staying on top of the blight control programme across such a large area is a major logistical challenge. The sprayer will work around the clock when required, kitted up with GPS auto-boom cut off that can facilitate accurate application at night.

Mr Wilcox believes such technologies are essential to maintain the most accurate application.

"Spraying opportunities are always an issue. Ideally we stick to a seven-day interval, especially when there are any risky periods of infection. But if that gets stretched to 10 days, then we rely on good fungicides that will give us a bit of a safety-net against delays,"advised Mr Wilcox. "If there's any risk of rain then we'll opt for the rainfastness of Revus, which has proven really effective."

He adds that availability in 10-litre S-pacs makes Revus easy to use, with faster sprayer turnaround to maintain high output. "Any fungicide that causes frothing in the tank or requires extra packaging to open and wash out can seriously reduce the sprayer's acreage covered per day."

Last season Mr Wilcox also moved to air-induction Amistar nozzles for blight applications. These incorporate an angled spray pattern for good crop penetration, but also reduce the risk of drift and can enable operators to spray in conditions that would compromise conventional nozzles, he added.

Potato growers and agronomists can view their local five-day BlightCast and Spray Window Forecast by simply logging on to this website. "Historical reviews of when Smith Periods occurred have little value in protecting potato crops from blight attack,"according to Tom Whitworth. "Now growers can be far more pro-active in their product selection and their programme scheduling for improved blight control and ultimately better crop quality."