A NEW early warning system for blight is now available for potato growers.

The Syngenta BlightCast system will give growers and agronomists a five-day advance warning of localised blight risks. It has been developed to enable risk-based selection of appropriate fungicides and ensure application at the right time to prevent infection.

Syngenta’s potato manager, Andrew Curtis, said: “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.

“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 three years.”

It had been activated earlier this year to aid spray timing and product selection right from the start of the season.

While conditions remained cool during the early stages of establishment, there was a greater risk of infection from bight zoospores and their motility through soil moisture.

Once crops were growing through the rapid canopy development phase, he suggested the use of Revus when BlightCast indicated risk of disease attack.

Mr Curtis said that growers must be alert to the risk of blight from first emergence, with no room for complacency.

“Although early infection may be contained or suppressed by subsequent blight spray applications, if there is any interruption in protection – or conditions turn highly conducive to blight – there’s a real risk of a rapid outbreak that could prove devastating,” he warned.

“It is crucial to stop localised hot-spots developing.”

Furthermore, he highlighted that trials have shown even a very low incidence of early foliar blight can result in relatively high levels of tuber infection at harvest.

“This really emphasises the importance of effective blight control, and reinforces the use of robust programmes with reliable products from the earliest applications.

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.