Phytophthora ramorum found in japanese larch

[davecorbin86]

The notifiable disease Phytophthora ramorum was first found in the UK in 2002. In the wider environment it has largely been associated with Rhododendron species that act as a host from which spores are produced. When produced in sufficient quantity these can infect trees and other plants in the vicinity, including the heathland plant bilberry (Vaccinium myrtillis). Until late last year control efforts in woodlands focused primarily on removing Rhododendron.

 

However, in August 2009 Phytophthora ramorum was found on a small number of dead and dying Japanese larch (Larix kaempferi) in the South West. This was of particular concern because some of the affected trees were not close to infected rhododendron. Subsequent testing at sites in north and west Devon and west Somerset confirmed the presence of Phytophthora ramorum in mature Japanese larch as well as species in its understorey, including Rhododendron, sweet chestnut, beech, birch, oak, Douglas fir and Western hemlock. On some sites there is little or no rhododendron present. These findings highlighted a significant change in the dynamics of the disease experienced previously where tree infection had only occurred in close proximity to infected Rhododendron. It is now known that Japanese larch can produce very high quantities of disease-carrying spores when actively growing in spring and summer, at much higher levels than those produced by Rhododendron. These may be spread significant distances in moist air.

[tommer9]

Good thread. It was actually found quite a long tinme before that, possibly as far back as 2007, but it was kept quiet for a long time for various reasons.

[davecorbin86]

i heard an infected tree can be temporarily treated by injecting something into it , is that true ?

[dangerous brian]

Its also found in the cheap German import the forester i spoke to reckoned its been here visible for 5 years at least,this all reeks of the foot and mouth saga that Defra blew out of proportion.

[davecorbin86]

do they not know what bleeding canker looks like ??!!

[davecorbin86]

FOUND THIS ON HORTICULTURE WEEK

 

 

The lethal tree pathogen Phytophthora ramorum has been found on Japanese larch trees (Larix kaempferi) in Northern Ireland for the first time.

 

The tree is a significant timber crop, covering 2,500ha of Department of Agriculture & Rural Development (DARD) land.

 

According to David Small, chief executive of DARD's forest service: "The disease has the potential to cause significant damage to larch trees and the wider environment. Infected Japanese larch on both public and private land will be felled."

 

Visitors to the province's forests are also being asked to stick to paths and to remove soil from footwear before leaving, he added.

 

More than 30 sites in Northern Ireland have reported the presence of P. ramorum in the past eight years, mostly on Rhododendron. Native Woodland Trust director Jim Lawlor called on the authorities to prioritise the removal of Rhododendron from woodlands, saying they were a pest to other species.

[monkeypuzzle22]

Great thread...i think we have underestimated for a long time the damage this pathogen could cause!