Re: Sudden Oak Death linked to rhododendrons
Diane wrote:
> >From information at the Sudden Oak Death sites, it appears
> to be almost totally destroying the 3 species of oak, all
> native to California. So far, European oaks have not
> contracted it.
>
> As I grow almost 300 species and hybrid rhododendrons
> adjacent to native Garry oak stands, I am following this
> with great interest.
>
> Further information on this Phytophthora:
> It is a new species first isolated on ornamental
> rhododendrons in Germany and The Netherlands in 1993 and is
> genetically distant to most of the other 60 species within
> the genus Phytophthora. The closest relative in the genus
> is P. lateralis, a virulent pathogen of Port Orford Cedar.
> P. lateralis is known to be present in natural stands of
> P.O. Cedar in the Pacific Northwest and occasionally on P.O.
> Cedar stock in nurseries in Europe.
>
> Perhaps there is another host species which is contaminating
> both rhododendrons and oaks. Perhaps it is a native fungus
> that went through a mutation due to environmental changes or
> proximity of a new host species. Certainly there is a free
> exchange of rhododendron material between California and the
> Port Orford Cedar habitat in Oregon, not to mention Port
> Orford Cedars. (I am drawing this connection myself which
> is not supported by information at the sites.)
>
Diane
Thanks for this further information. I find it very interesting in an
academic sort of way, but thank goodness at present no more than that.
We grow a great many Rhododendrons here(In fact our Puketi garden is
ranked #2 of the world's great Rhodo collections) and also have a
cnsiderable number of species of oaks from both Europe and America, but
one hopes our local control authorites are sufficeintly aware of the
danger and that our pretty strict quarantine regukltins will be enough
keep this particular fungus out.
Moira
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata (near Wellington, capital city of New Zealand)
