The warning comes as Devon was declared the 17th county in the UK where Chalara dieback of ash was confirmed and is now present in 525 sites, including 185 outside managed areas.
The UK government is putting into action plans developed this year for both ash dieback and Phytophthora to act swiftly to identify and tackle new outbreaks.
Confor said the extent of P ramorum found in larch in south-west Scotland this spring was on a massive scale and had been confirmed as the virulent EU2 strain.
Action was needed to help woodland owners restock, said Confor’s Scotland manager Jamie Farquhar.
“We knew the writing was on the wall for more bad news this year, but we are shocked to learn the true extent of the new outbreak. This is going to impact severely on private sector woodland owners as well as on the national forest estate,” he said.
Aerial surveys in England have revealed up to 525ha of larch woodland as possibly infected, an increase of 26%.
Confor chief executive Stuart Goodall said: “The domestic wood industry has had great success recently in winning market share.However, the market is predominantly spruce and absorbing and marketing significant proportions of larch poses a challenge. Sadly, some infected larch crops will be inaccessible, immature or plainly uneconomic to harvest.”
The technical review earlier this year of the Defra Phytophthora management programme said there continues to be a gap in knowledge of infection of larch, leading to a lag between infection and felling, which affects efforts to prevent the spread.
The main thrust of recommendations to be considered later this month are to continue funding research and action with sufficent resources to control and eradicate Phytophthora.
