POTATO GROWERS should maintain blight fungicide programmes until the haulm is completely dead following desiccation, the British Potato Council (BPC) has advised.

While blight risk is generally low and is now unlikely to adversely affect yields, there is a significant risk of tuber blight should the weather turn unsettled, said ADAS’s Nick Bradshaw.

“Even slight haulm infection can result in significant tuber infection given the right conditions…so attention should continue to be focused on protecting tubers.”

BASF’s Dave Marris agreed. Urging growers not to neglect spray programmes, he said that keeping blight out of tubers now, could save problems at store loading.

“It’s all too easy to let them [spray intervals] stretch when there is so much else to do but remember that at this stage you’re protecting your marketable yield.”

In Scotland the last blight outbreak was on July 26, but growers should continue to build spray programmes around fungicides with good activity against tuber infection, added Ruairidh Bain, from the BPC’s blight advisory team.

“The majority of crops will be free of blight, but where there is some foliar blight, humid conditions, significant rainfall and cracks in the ridges, this could lead to tuber infection.”

Fungicide intervals should be appropriate to the local risk, he said. See www.potato.org.uk/blight for latest disease reports in your area.

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