A NEW tree disease has been confirmed for the first time to cause resinous cankers on Western Hemlock.  

Forest Research officials say the effects of Phytophthora pluvialis were found in seven- to eight-year-old trees that had initially been infected in Cornwall, England. 

In a first-of-its-kind report, scientists isolated several samples of the species from the site for three months and confirmed the symptoms by extensive tests. Cankers had previously been observed in the field, but the research now shows a direct link to P. pluvialis. 

READ MORE: What is Phytophthora Pluvialis? Everything we know so far

The report stated: "Pathogenicity tests were done on seven– to eight-year-old western hemlock. A representative isolate of P. pluvialis was used in the trial and six trees were inoculated on stem and branches. 

"After three months, chlorosis of needles close to inoculation points was observed, followed by more widespread needle necrosis and needle cast.

"Cankers formed on inoculated trees were similar to those observed in the field. 

Forestry Journal: Lesions caused by Phytophthora pluvialis observed on western hemlock three months after inoculation.Lesions caused by Phytophthora pluvialis observed on western hemlock three months after inoculation.

"This is the first published report of P. pluvialis causing resinous cankers on western hemlock worldwide." 

Having been discovered in every part of mainland Britain, steps have been taken to fight back against the disease's spread.

READ MORE: Phytophthora pluvialis: What can the spread of Phytophthora ramorum tell us about the outbreak?

Demarcated zones have been set up in the likes of Cornwall, Loch Carron and Gwynedd, with restrictions on timber movement among the measures imposed. 

While it's too early to tell just how serious P. pluvialis, which can also affect the likes of Douglas Fir, could be, there is some concern it could "inflict on [the species] what Phytophthora ramorum did to Japanese larch". 

A Forest Research statement read: "Following the discovery of Phytophthora pluvialis in woodland in Cornwall, we've been conducting analysis which confirms that Phytophthora pluvialis is the direct cause of the symptoms observed on the trees." 

Read the full report, published by the British Society for Plant Pathology, here.