Record year for potato blight and Smith Periods

2007 has been a record year for potato blight, according to results from the British Potato Council’s combined Fight Against Blight and Blightwatch service.

In total 301 blight outbreaks were confirmed (see map below), more than twice the previous highest recorded. In addition, double the average number of Full Smith Periods were recorded in June and July (2200 in June, compared with 800).

“It’s a phenomenal number of Smith periods so early on in the year that has been the main cause of problems we have experienced with blight,” said BPC agronomist, Mark Prentice.BPC blight map

“We had a high disease pressure just as crops were laying down their canopy, which means the biggest potential for infection of unprotected growth.”

The problem was compounded by appalling summer weather, which favoured blight development and severely disrupted many spray programmes, he added.

The high level of tuber blight had also raised concerns for the stored crop and growers were urged to follow recommendations in the updated Growers Advice Sheet number 13 or call the BPC storage advice line free on 0800 02 82 111.

Around 1500 users signed up for the blight service, and over 2000 positive isolates were sent for SCRI analysis. “This will give us some good data we can use to track how A1 and A2 populations are developing in time for next year,” Mr Prentice said.

Email and mobile alerts have stopped for this year, but full analysis of the samples will be available in time for British Potato 2007 at the Yorkshire Event Centre, Harrogate on 28-29 November.