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Home > Archive > UK gardening > April 2007 > possible Phytophthora ramorum in Viburnum tinus
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possible Phytophthora ramorum in Viburnum tinus
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| Hi
I bought a large (4ft) container-grown Viburnum tinus from a supplier in
Leicestershire in late February.
It seemed fairly healthy when it arrived apart from some small black-spot lesions on
the older growth.
It has been planted in semi-shade with sun all morning and again in the later
afternoon and evening and is sheltered from the prevalent south-westerly winds.
Although we are costal north Cumbria we get very little wind coming from the north to
carry any potential salt spray. The Viburnum was planted in a well-prepared hole
with FYM and blood, fish and bone. It has been regularly watered and this spring it
has been liquid fed on several occasions since planting as it has started to look
poorly. Since planting we have had frost on one or two nights and even then only mild
frost.
Over the last month or so, last year's growth has become yellowish and the black/grey
leaf lesions have spread. Some in-bud flower heads have turned brown and dropped -
others are now starting to open and look quite healthy. There is a reasonable amount
of leaf and bud drop but I can't see any characteristic stem lesions as yet.
I have contacted the nursery this morning as I was suspicious of Phytophthora ramorum
infection. Interestingly he said they had just had another shipment of Viburnum
tinus in from Italy (where I know it has been recorded) and he is investigating this
recent shipment for suspected Phytophthora ramorum infection.
I have just emailed some photos to the nursery and will send them some samples. I
have also saved some samples in the fridge in case I need to send to defra.
Maybe I'm just being a little neurotic but I have posted some images on my website
and I would be interested in comments, especially from people with experience of this
disease.
Many thanks
Liz
Images can be found at:
http://www.libtib.org.uk/viburnum/viburnum3.jpg
http://www.libtib.org.uk/viburnum/viburnum4.jpg
http://www.libtib.org.uk/viburnum/viburnum5.jpg
http://www.libtib.org.uk/viburnum/viburnum6.jpg
http://www.libtib.org.uk/viburnum/viburnum7.jpg
--
Posted via a free Usenet account from http://www.teranews.com
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| Treelady 2007-04-23, 1:25 pm |
| On Apr 21, 11:41 am, "Liz" <inva...@invalid.invalid> wrote:
> Hi
>
> I bought a large (4ft) container-grown Viburnum tinus from a supplier in
> Leicestershire in late February.
> It seemed fairly healthy when it arrived apart from some small black-spot lesions on
> the older growth.
> It has been planted in semi-shade with sun all morning and again in the later
> afternoon and evening and is sheltered from the prevalent south-westerly winds.
> Although we are costal north Cumbria we get very little wind coming from the north to
> carry any potential salt spray. The Viburnum was planted in a well-prepared hole
> with FYM and blood, fish and bone. It has been regularly watered and this spring it
> has been liquid fed on several occasions since planting as it has started to look
> poorly. Since planting we have had frost on one or two nights and even then only mild
> frost.
>
> Over the last month or so, last year's growth has become yellowish and the black/grey
> leaf lesions have spread. Some in-bud flower heads have turned brown and dropped -
> others are now starting to open and look quite healthy. There is a reasonable amount
> of leaf and bud drop but I can't see any characteristic stem lesions as yet.
>
> I have contacted the nursery this morning as I was suspicious of Phytophthora ramorum
> infection. Interestingly he said they had just had another shipment of Viburnum
> tinus in from Italy (where I know it has been recorded) and he is investigating this
> recent shipment for suspected Phytophthora ramorum infection.
>
> I have just emailed some photos to the nursery and will send them some samples. I
> have also saved some samples in the fridge in case I need to send to defra.
>
> Maybe I'm just being a little neurotic but I have posted some images on my website
> and I would be interested in comments, especially from people with experience of this
> disease.
>
> Many thanks
>
> Liz
>
> Images can be found at:
>
> http://www.libtib.org.uk/viburnum/v...m/viburnum7.jpg
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com
Phytopthora, so I have read, was introduced into this country via
Rhodendron and Viburnum on
imported nursery stock. The presence of Phytopthora has increased over
recent years,
the drought conditions weakens trees already susceptible to the
pathogen, giving it a stronger foothold.
Many Horse Chestnut trees, throughout the country, have suffered its
effects .
Personally, if I suspected my Viburnum had Phytopthora I would dig it
up and immediately burn it, and
(against my normal habits) disinfect (using a soap based one) the soil/
area in which it grew.Then I would
plant something that will withstand, even flourish, the changes we are
seeing in weather patterns.
Before such dramatic action, I would check a few things: the soil- is
it clay heavy,waterlogged, too dry;
did the roots dry out in transit? was it potbound? how sudden was the
onset of symptoms? etc.
I have only seen Phytopthora in trees, so I cannot help with
diagnosis. If you like your plant, investigate
the predisposing factors, then act.
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| On 23/4/07 17:46, in article
1177346817.187079.239750@o5g2000hsb.googlegroups.com, "Treelady"
<rebeccawoodnymph@hotmail.com> wrote:
<snip>
>
> Phytopthora, so I have read, was introduced into this country via
> Rhodendron and Viburnum on
> imported nursery stock. The presence of Phytopthora has increased over
> recent years,
> the drought conditions weakens trees already susceptible to the
> pathogen, giving it a stronger foothold.
<snip>
Do you have any opinion on when it came into the country? I ask because an
old Cornish nurseryman who used to run a nursery of high repute, told my
husband that he reckons Phytophthora has been around for a very long time
but unrecognised and unacknowledged or even, ignored. Your comment about
drought affecting its increase might, perhaps, tie in with warmer overall
temperatures causing the problem to become more prominent in terms of
awareness, too?
--
Sacha
http://www.hillhousenursery.co.uk
South Devon
http://www.discoverdartmoor.co.uk/
(remove weeds from address)
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"Treelady" <rebeccawoodnymph@hotmail.com> wrote in message
news:1177346817.187079.239750@o5g2000hsb.googlegroups.com...
> On Apr 21, 11:41 am, "Liz" <inva...@invalid.invalid> wrote:
on[color=darkred]
north to[color=darkred]
it[color=darkred]
mild[color=darkred]
black/grey[color=darkred]
dropped -[color=darkred]
amount[color=darkred]
ramorum[color=darkred]
this[color=darkred]
I[color=darkred]
website[color=darkred]
this[color=darkred]
http://www.libtib.org.uk/viburnum/v...k/viburnum/vibu
rnum4.jpghttp://www.libtib.org.uk/viburnum/viburnum5.jpghttp://www.libtib.org.uk/vibu
rnum/viburnum6.jpghttp://www.libtib.org.uk/viburnum/viburnum7.jpg[color=darkred]
>
> Phytopthora, so I have read, was introduced into this country via
> Rhodendron and Viburnum on
> imported nursery stock. The presence of Phytopthora has increased over
> recent years,
> the drought conditions weakens trees already susceptible to the
> pathogen, giving it a stronger foothold.
> Many Horse Chestnut trees, throughout the country, have suffered its
> effects .
> Personally, if I suspected my Viburnum had Phytopthora I would dig it
> up and immediately burn it, and
> (against my normal habits) disinfect (using a soap based one) the soil/
> area in which it grew.Then I would
> plant something that will withstand, even flourish, the changes we are
> seeing in weather patterns.
>
> Before such dramatic action, I would check a few things: the soil- is
> it clay heavy,waterlogged, too dry;
> did the roots dry out in transit? was it potbound? how sudden was the
> onset of symptoms? etc.
> I have only seen Phytopthora in trees, so I cannot help with
> diagnosis. If you like your plant, investigate
> the predisposing factors, then act.
The nursery were in touch this morning and a defra inspector is on his/her way.
However the Italian supplier said that the symptoms "were normal" for this time of
year.
I sent samples to the nursery which should have arrived today. The nursery say they
will phone once defra have been but they have been very good and said whatever the
outcome, they will refund or replace.
We took a drive around last night after checking the sheep and looked at a few V.
tinus - none of them showed the symptoms that ours is showing - some had the odd
brown mark and some had some road-salt damage but they all looked quite healthy. The
nursery also said he wasn't in agreement with the Italian supplier and that is why he
has called in defra.
Either way, I think it's coming out as even if it is not Phytophthora ramorum the
poor thing is seriously not happy. I would have to severely cut it back to about
half it's height which defeats the purpose of spending the money on a large shrub in
the first place. It was bought to quickly screen the "kitchen garden" from the front
of the house.
The plant was not pot-bound or dried out. It was very well wrapped and protected.
We are on gravel/sand with about 6 inches of "good" soil. However the planting hole
was very well prepared - dug put about twice the depth of the pot and about 3 time
the diameter and filled with a mix of "good" topsoil, FYM and a handful of blood,
fish and bone. We haven't had rain for over a month (until yesterday) so I have been
watering it well as I've had to go around and water a lot of other things too - newly
planted greengages, plums, climbing roses and clematis.
It came with some leaf lesions but did fine for a while - it's only been in the last
few weeks that it has really started to look very ill with the yellowing of last
year's growth and other symptoms mentioned above.
If it turns out to be Phytophthora ramorum I have a lot of work ahead I know!
Thanks
Liz
--
Posted via a free Usenet account from http://www.teranews.com
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| On 21 Apr, 11:41, "Liz" <inva...@invalid.invalid> wrote:
> Hi
>
> I bought a large (4ft) container-grown Viburnum tinus from a supplier in
> Leicestershire in late February.
> It seemed fairly healthy when it arrived apart from some small black-spot lesions on
> the older growth.
> It has been planted in semi-shade with sun all morning and again in the later
> afternoon and evening and is sheltered from the prevalent south-westerly winds.
> Although we are costal north Cumbria we get very little wind coming from the north to
> carry any potential salt spray. The Viburnum was planted in a well-prepared hole
> with FYM and blood, fish and bone. It has been regularly watered and this spring it
> has been liquid fed on several occasions since planting as it has started to look
> poorly. Since planting we have had frost on one or two nights and even then only mild
> frost.
>
> Over the last month or so, last year's growth has become yellowish and the black/grey
> leaf lesions have spread. Some in-bud flower heads have turned brown and dropped -
> others are now starting to open and look quite healthy. There is a reasonable amount
> of leaf and bud drop but I can't see any characteristic stem lesions as yet.
>
> I have contacted the nursery this morning as I was suspicious of Phytophthora ramorum
> infection. Interestingly he said they had just had another shipment of Viburnum
> tinus in from Italy (where I know it has been recorded) and he is investigating this
> recent shipment for suspected Phytophthora ramorum infection.
>
> I have just emailed some photos to the nursery and will send them some samples. I
> have also saved some samples in the fridge in case I need to send to defra.
>
> Maybe I'm just being a little neurotic but I have posted some images on my website
> and I would be interested in comments, especially from people with experience of this
> disease.
>
I haven't knowingly seen P. ramorum but that's not a happy plant so
it's as well you're getting
the DEFRA inspector to look. They won't be able to tell you straight
away but they have a quick test
that will show up if there's any Phytopthora species present and if
it's a positive test they will send it
to their lab for a positive identification. There is one suggestion I
can make having read your description
of the post planting care. I do wonder if you've been a bit too 'kind'
to it?
Were the FYM and fertiliser well mixed with the soil?
The FYM and fertiliser were sufficient to last at least until the
plant was growing away, so all you
needed to do was water during the dry weather.
Liquid feeding an already sickly looking plant is almost certain to do
further damage to roots that are
damaged or dying.
Rest and a quiet life is what a sickly plant needs most if you aren't
sure what the problem is.
Viburnums are funny things, they are susceptible to just dying without
any obvious reason so
I hope yours is one of those.
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"Rod" <rodcraddock@lineone.net> wrote in message
news:1177448831.291821.77490@u32g2000prd.googlegroups.com...
> On 21 Apr, 11:41, "Liz" <inva...@invalid.invalid> wrote:
snip stuff about sickly Viburnum
Hi Rod
> I haven't knowingly seen P. ramorum but that's not a happy plant so
> it's as well you're getting
> the DEFRA inspector to look. They won't be able to tell you straight
> away but they have a quick test
> that will show up if there's any Phytopthora species present and if
> it's a positive test they will send it
> to their lab for a positive identification.
It is definitely not a happy plant but I have hopes that it may survive - the older
growth doesn't seem to badly affected so it may have a chance.
Defra went to the nursery which suppled the V. tinus and actually did an "instant"
test on samples from the nursery and on my samples I sent to the nursery. The test
kit is a bit like a pregnancy test. Seemingly a line appears on the tester strip if
it is P. ramorum. Thankfully this test came back negative but defra have taken the
samples away for further analysis and will get back to us with results and any
treatment. I suspect they will suggest a fungicide. I may then have to decide
whether to use it or not as I'm trying to be as organic as possible and try not to
use any chemicals in the garden, especially the vegtable garden.
The nursery have been very good about this and will accomodate any decision I make.
>There is one suggestion I
> can make having read your description
> of the post planting care. I do wonder if you've been a bit too 'kind'
> to it?
> Were the FYM and fertiliser well mixed with the soil?
The FYM and B,F&B were very well mixed with the topsoil and a "protective" layer of
ordinary topsoil placed on top of the mix to a depth of a few inches to stop the
roots coming in direct contact with any FYM to begin with. The planting hole was
quite large to account for the poorish soil/gravel/sand we have here.
It got two feeds of weak organic seaweed liquid separated by aboutt 2 weeks Apart
from that, nothng moreexcept watering as we've had no rain for over a month.
> The FYM and fertiliser were sufficient to last at least until the
> plant was growing away, so all you
> needed to do was water during the dry weather.
> Liquid feeding an already sickly looking plant is almost certain to do
> further damage to roots that are
> damaged or dying.
I will not feed it any more then.
> Rest and a quiet life is what a sickly plant needs most if you aren't
> sure what the problem is.
Ok, I'll leave the poor thing alone, apart from any necessary watering and walking
past and making encouraging noises :-))
> Viburnums are funny things, they are susceptible to just dying without
> any obvious reason so
> I hope yours is one of those.
I wasn't aware they were so touchy - I always thought they were pretty tough.
Many thanks
Liz
--
Posted via a free Usenet account from http://www.teranews.com
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| On 24 Apr, 22:59, "Liz" <inva...@invalid.invalid> wrote:
> "Rod" <rodcradd...@lineone.net> wrote in message
>
> news:1177448831.291821.77490@u32g2000prd.googlegroups.com...
> I wasn't aware they were so touchy - I always thought they were pretty tough.
>
Well normally they are which makes the sudden deaths so surprising and
difficult to explain. While most nursery grown plants are healthy the
odd bad one gets through, for instance in container grown plants you
can get the odd case of Phytophthora cinamomi (sp?) which is spread
through irrigation water on poorly drained standing grounds.
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"Rod" <rodcraddock@lineone.net> wrote in message
news:1177621466.432898.157830@r35g2000prh.googlegroups.com...
> On 24 Apr, 22:59, "Liz" <inva...@invalid.invalid> wrote:
>
> Well normally they are which makes the sudden deaths so surprising and
> difficult to explain. While most nursery grown plants are healthy the
> odd bad one gets through, for instance in container grown plants you
> can get the odd case of Phytophthora cinamomi (sp?) which is spread
> through irrigation water on poorly drained standing grounds.
It does look like this has been a bad batch. Defra will get back to us, hopefully
this week, to let us know what the problem is.
Many thanks for your informative replies.
Liz
--
Posted via a free Usenet account from http://www.teranews.com
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