'Urgent need for resistant seed'

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04 January 2024
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Conference puts PCN and blackleg in the spotlight.

THE spotlight was firmly on PCN and blackleg at this year's CUPGRA (Cambridge University Potato Growers’ Association) conference, which took place just before Christmas.

Agronomist Eric Anderson spoke about the current problem faced by the seed sector in Scotland, where globodera pallida is proving a major pest to crops, while Prof Ian Toth, of the James Hutton Institute, discussed the link between free-living nematodes (FLN) and blackleg.

Infestations of PCN have been multiplying, and data shows there are more than double the rates that there were around eight years ago, Eric told those at the conference, adding that growers must have a SASA clearance certificate for land before they can plant.

Few potato varieties are resistant to the pest and authorisation for the nematicide Nemathorin (fosthiazate) will be withdrawn on October 31st. Eric said this will present a new challenge for the Scottish seed and ware industries, adding that trap crop establishment has been 'inconsistent' in Scotland.

“We urgently need varieties that have both resistance and tolerance to PCN,” he said.

Awareness needs to be raised with land agents, as the problems are more prolific on rented land where landlords only consider short-term gains rather than looking at long-term soil health, Eric told those at the conference. With that in mind, a programme entitled PCN Action Scotland is targeting those involved with renting seed potato land, which will detail integrated pest management.

“An integrated control programme requires co-ordination at all levels,” said Eric.

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Meanwhile, root damage by free living nematodes (FLN) could be an important factor in blackleg pectobacterium atrosepticum infection, revealed Prof Ian Toth, of the James Hutton Institute, who held a workshop at the conference.

Sharing latest research being funded by Scottish Government, Defra, BBSRC and NERC through the Bacterial Plant Diseases Programme, he said blackleg causes significant losses in the British potato industry, with losses reaching £50m. The team at the James Hutton Institute, in collaboration with the University of Dundee, have been looking at the damage caused to roots by FLN, which they believe is providing an entry point for blackleg bacteria.

He said blackleg bacteria can sense when the root is damaged and colonise there within a couple of days.

The team has been looking at ways of reducing incidence and harnessing microbial populations to defend the plant, as well as breeding varieties that have more resistant roots, Ian said.

“We already know that pectobacterium produce bacteriocins which kill their close relations and, working with the University of Glasgow, we are exploring whether we could use this to protect infection,” he said.

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