Increasing Threat from P. ramorum

[Mark T]

The number of infected sites and species is increasing...

 

Forestry Commission - News - tree disease outbreaks confirmed in devon, cornwall and somerset

[TimberCutterDartmoor]

Glad you raised this;

 

Has had a direct on my work recently...

 

http://arbtalk.co.uk/forum/tree-health-care/10228-phytophthora-ramorum.html

[Dean O]

Maybe someone can clear something up for me.....

 

P ramorum causes Sudden oak death infects beech etc, hosts can be rhodys viburnums etc and is fungal. It causes bleeding cankers and leaf legions

 

where i get confused is ......

 

i was under the impresion that pseudomonas syringea (bacterial) is now thought to be the likely culprit causing bleeding canker in horse chestnut (rather than p ramorum as originally thought).

 

do both diseases have the same/ similar symptoms or is there a link.

does pseudomonas only attack hc, does p ramorum not infect HC?

[Mark T]

Maybe someone can clear something up for me.....

 

P ramorum causes Sudden oak death infects beech etc, hosts can be rhodys viburnums etc and is fungal. It causes bleeding cankers and leaf legions

 

where i get confused is ......

 

i was under the impresion that pseudomonas syringea (bacterial) is now thought to be the likely culprit causing bleeding canker in horse chestnut (rather than p ramorum as originally thought).

 

do both diseases have the same/ similar symptoms or is there a link.

does pseudomonas only attack hc, does p ramorum not infect HC?

 

 

There have been instances where P. cactorum and P. citricola have caused bleeding cankers on HC but, following increased study, it is now thought that most bleeding canker on HC is caused by the bactreria Pseudomonas syringae pv. aesculi. Pseudomonas bacteria affect a wide range of hosts and cause a wide range of symptoms - as do Phytophthora species (the irish potato famine was caused by P. infestans).

 

Maybe these pages will help...

 

Forest Research - Bleeding Canker of Horse Chestnut - Diseases with similar symptoms

[Dean O]

thanks Gimmer.

from what ive read if rhody's arent near by then any bleeding cankers are bound to be syringae. would you agree?

also syringea is the most likeley cause of cankers in HC's

the pictures of the cankers themselves are similar in both syringae and p. ramorum

[alliaria]

Hi,

I think the real concern is the change of host and the absence of Rhodys nearby, can P. ramorum miss out the Rhody part of it,s infective cycle? If so, we could be in lots of trouble.

[TimberCutterDartmoor]

Until a month or so ago I was buying hardwood thinnings from Cann Wood (where this is currently being investigated). I was handed a defra summary re P.Ram and of course Rhodies featured. Then I assumed, wrongly and having never been in there, that the lack of aggression in rhody control in there was an issue. Seemingly no rhody in there! Like you say, a bit nerve wracking...

[tommer9]

There is evidence that Laryx spp. esp l. kaemferii (sp) is a host, and there have been studies on P. ramorum and P.kernovii that show the infection spreading FROM larch TO Rhodies. That is even more worrying given how much Larch is in plantation in this country.

[TimberCutterDartmoor]

There is evidence that Laryx spp. esp l. kaemferii (sp) is a host, and there have been studies on P. ramorum and P.kernovii that show the infection spreading FROM larch TO Rhodies. That is even more worrying given how much Larch is in plantation in this country.

 

I wonder if it's got anything to do with the fact that they don't spray the stumps with urea anymore? Why did they stop doing that? Used to have flippin great tanks of blue slosh on the back of the harvester, oregon bars with holes etc - seems to have vanished???