Mystery disease attacking evergreen shrubs - please help identify
 

Hi folks,

First time post on Garden Banter. To business.

I've attached three photos taken yesterday. They show a disease which is attacking evergreen shrubs, such as myrtle and azalea, owned by people for whom I work as a gardener. The leaves go brown, with darker spots, as shown, then fall off. Maybe the shrubs will grow new leaves next year, but intuitively I am not hopeful.

If you could help ID the pathogen and suggest a preventative/curative measure, I'd be pretty blimmin grateful.

Yours,

Steve

Mystery disease attacking evergreen shrubs - please help identify
 

On 20/10/2017 14:51, stevejdowning wrote:
Hi folks,

First time post on Garden Banter. To business.

I've attached three photos taken yesterday. They show a disease which is
attacking evergreen shrubs, such as myrtle and azalea, owned by people
for whom I work as a gardener. The leaves go brown, with darker spots,
as shown, then fall off. Maybe the shrubs will grow new leaves next
year, but intuitively I am not hopeful.

If you could help ID the pathogen and suggest a preventative/curative
measure, I'd be pretty blimmin grateful.

Yours,

Steve


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I'm seeing it uk.rec.gardening on Usenet where the newsgroup that
gardenbanter parasitises really exists without adverts.

I have a bad feeling that it might be phytophtora fungal attack of the
roots which has become a serious nuisance in some important gardens. It
only shows in the leaves when it is ready to reproduce with spores.

http://extension.oregonstate.edu/lin...heet_-_OSU.pdf

(a US example but happens to show myrtle)

RHS version of plants affected here

https://www.rhs.org.uk/advice/pdfs/p...-host-list.pdf

If it is this then you need a disinfectant bath at each site since your
boots will spread the fungus to new sites (I'm not convinced this works
but it is what I have seen done on sites where the thing is endemic).

--
Regards,
Martin Brown

Thanks kindly for the prompt and extensive reply Chris! Looks like we're in the same neck of the woods too - I'm in Falmouth :)

Doubt it because it seems to be creeping very definitively from left to right on a particular hedge, sort of like a fluid moving through blotting paper, but in very slow motion. I would have thought an aphid infestation would be more uniformly distributed throughout the hedge.

Not a bad shout. Even if it's off-season, it seems a better approach than standing around twiddling one's thumbs.

Roger that!

I doubt it's any of these. I mean, in Falmouth, myrtle in particular is virtually bomb-proof and self-seeds like mad. We've not had any frosts yet, to the best of my knowledge.

The damage is way high for any animals to have peed it on, unless some Brontosauruses are doing the rounds behind my back!

I've since seen the same problem on a similar shrub at a property about half a mile away today. Might be something of an epidemic in the making...

All great stuff, many thanks!

Crikey, there's a thought. Hopefully not - the second case, which I say on Friday, was on a shrub I haven't done anything to in months and months.

Sorry Martin, hadn't noticed your reply too. Thanks for that as well. Interesting but no surprising that other occurrences are cropping up...

Mystery disease attacking evergreen shrubs - please help identify
 

On 22/10/2017 14:33, stevejdowning wrote:
All great stuff, many thanks!

Is that a garden you visit regularly? An uncomfortable thought - could
you have spread it on your boots or tools?
Crikey, there's a thought. Hopefully not - the second case, which I say
on Friday, was on a shrub I haven't done anything to in months and
months.


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I am surprised no one has asked about the state of the backs of the leaves.
Also have you thought of sending the pics to the RHS for their opinion?

It's been a week since those initial pictures were posted. I've been back today to the property where the photos were taken. The gent who owns the garden has been doing some research of his own. Partially thanks to him having a better camera on his phone, a new culprit might have been found (attached photo).

According to a friend of his who works at the Eden Project, they're Privet Thrips. The friend who is working at Eden is going to go round on Sunday apparently, so I might have a better idea of what's going on and how to treat it from that visit. Not that I will be there personally, but will get the update second hand.