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Now available free on-line, it will give potato growers and agronomists a five-day advance warning of localised blight risks. BlightCast has been developed to enable risk based selection of appropriate fungicides and ensure application at the right time to prevent infection.

Mr Farrow highlighted that the increased incidence of blight after an incredibly difficult season last year has left a legacy of potential infection sources from discard dumps, volunteers and seed. “Furthermore, the cold soils and slow start to growth after planting this year means that most crops are now emerging at the same time and with simultaneous exposure to risk; that could further stretch growers’ capability to maintain appropriate blight control programmes through the season.”  

He reported that BlightCast has been activated early this year to aide spray timing and product selection from the start of the season. He pointed out that whilst conditions remain cool during the early stages of establishment, there is a greater risk of infection from blight zoospores and their motility through soil moisture, where growers and agronomists should be focusing on Shirlan for initial TO applications.

Once crops are growing through the rapid canopy development phase, Mr Farrow advocated the use of Revus when BlightCast indicates risk of disease attack. The positive movement of mandipropamid across the expanding leaf area offers highly effective protection against infection, which makes Revus the leading foliar blight fungicide in the Euroblight listings.

BlightCast calculation of conditions conducive to blight are also invaluable for helping make proactive agronomy decisions, such as when to include a cymoxonil tank-mix for additional kick-back activity, or assessing how to cope with more aggressive strains of blight that could be active at lower temperatures, he added.    

“In the past growers have relied on weather records indicating Smith Periods when blight risk had already occurred. That was after the event, and when it was too late to make preventative applications,” said Mr Farrow. 

“Now we have the technology and capability to forecast when conditions conducive to blight are likely to occur, and give growers the chance to take positive action to minimise the risk of infection. BlightCast has proven to be extremely valuable and reliable over the past four years.”

Spraying opportunities

Positive feedback on BlightCast from growers has highlighted how using the forecasting system in conjunction with Syngenta website information of spray window opportunities, can help with spray scheduling ahead of disease risk periods. “If BlightCast foresees disease risk rising, but the Spray Window Forecast indicates application is going to be difficult, it may be better to get the necessary protection on early,” advised Mr Farrow. “Fortunately the ease-of-use and rapid rainfastness of Revus, along with the use of Syngenta low-drift nozzle technology, can help growers make timely applications in a difficult season.”

Free BlightCast registration

BlightCast is free to all potato growers and agronomists registered on the Syngenta website. The local forecasts are defined by postcode, enabling those with crops across a wide geographical area to easily keep a track of conditions and risks. To register, log on to www.syngenta.co.uk