Confor plant health statement

19 March 2018

Confor has reassured members that the impact of small, isolated findings of Phytophthora ramorum on Sitka spruce are likely to be “localised and minimal”.  

In response to a request for comment from the Sunday Herald, Confor Chief Executive Stuart Goodall said:"Sitka spruce is a mainstay of Scotland's forestry and wood processing industry, which is worth £1 billion annually to the economy and supports more than 25,000 jobs.  Therefore, we take this news very seriously, and are working closely with Forestry Commission Scotland and Forest Research.  

"However, one of the main attributes of Sitka spruce is its historic resilience to pests and diseases, as well as its ability to thrive in a variety of soils.  It is well-known that Sitka spruce can be affected by P. ramorum, but we are reassured by past experience - and by the positive view of Forest Research experts - that the impact is very likely to be localised and minimal, due to Sitka's natural resistance." 

The background to the story is thatin 2017, the Scottish tree health aerial reconnaissance and follow-up ground surveys discovered two small isolated findings of P. ramorum on Sitka. This was picked up by a Sunday Herald journalist. The link to his story is here.

Confor has been in close contact with Forestry Commission Scotland’s tree health team, and with Forest Research’s leading pathologist Dr Joan Webber.  The advice is that the Sitka were in the vicinity of infected larch, and were likely to have already been in poor health due to factors such as climatic impacts and poor soils.

Although larch has been the main species affected by P. ramorum in the UK, we know that other conifer species can become infected, and indeed, these findings are not the first on Sitka.  Several years ago, isolated findings were made on this species in Northern Ireland, Wales and Kintyre, yet none of these have shown any sign of disease progression in to neighbouring spruce trees. 

While we know Sitka can act as a sporulating host for the pathogen, its capacity to do so is at a much lower level then when compared with larch.  Furthermore, Forest Research reports that the likelihood of the disease mutating so that other species sporulate to the same degree as larch is extremely unlikely.  This was Confor’s principle concern at the onset  of the outbreak of the disease on larch back in 2010.  There is still a strategy for removing infected material quickly (e.g. larch and rhododendron) to help slow the spread and impact of the disease, and reduce the opportunity for the pathogen to mutate. 

All our major conifer species have been exposed to P. ramorum within the management zone for a number of years, and only larch has been significantly impacted.  Furthermore, as larch is our only common species of softwood that sheds all its needles annually, and it is believed that the greatest sporulation occurs in the period shortly before the needles are shed, it is likely to be the only species that will become a significant sporulating host.

If members have any queries, they should contact their national manager as follows:

England         Caroline Harrison     

Scotland        Jamie Farquhar

Wales            Martin Bishop