April 22 - 30 2010 mailing list messages

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From: Geoffrey Hands
To: Orchid Talk List
Subject: two questions about virus
Date: Sat, 24 Apr 2010 14:05

I have this spotted foliage problem on a few nobile type dendrobium hybrids,
and a few other dendrobiums too − one is a hybrid in what used to be called
the nigro-hirsute section ( like D.infundibulum) another is a kingianum -
but only one or two of my few dozen kingianum type plants is affected; maybe
a third of my nobile tupes are affected.

I thought at first it is a nutrient deficiency , and have taken it along to
show to two different extremely experienced professionals. Both confessed
themselves puzzled. One suggested I try an Epsom salts spray ( Mag
sulphate). The other wondered if the pH was wrong. Neither suggested virus .

I have seen and had experience of the two common ones − cymbidium mosaic
virus, and the ring worm sort occasionally seen on odontoglossums. This is
different.

But then having thought it may be a virus I can't get the idea out of my
head .I am tempted to burn them all, but before I do this, I thought to ask
here.

I have also thought of buying a kit and doing a virus test , but can't find
the address in the Orchid mags I have on my shelf.

From: N & T Burgess
To: Orchid Talk List
Subject: Orchid Virus Test
Date: Sat, 24 Apr 2010 20:00

Geoff the address you want for the virus testers is http://www.pocketdiagnostic.com

From: Paul Johnson
To: Orchid Talk List
Subject: Re: [OrchidTalk] two questions about virus
Date: Sat, 24 Apr 2010 20:20

Rather than a virus, I suggest that this might be the early stages of
fungal infection from either Cercospora dendrobii or Septoria
selenophomoides. At least that is what strikes my memory banks.

From: Alex
To: Orchid Talk List
Subject: Re: [OrchidTalk] two questions about virus
Date: Sat, 24 Apr 2010 20:45

I have tried a test kit called 'Pocketdiagnostic' on a spotty odont, test was clear but the kit was expensive, about £15 as I remember. Easy to use. If its a cheap plant probably best to dispose of it.
Regards
Alex Scott

From: Lynda Coles
To: Orchid Talk List
Subject: Re: [OrchidTalk] two questions about virus
Date: Sat, 24 Apr 2010 21:45

The only virus kit vendor that I know of is in Thailand...the kits will test for CyMV and ORSV on the same cassette. If you are interested in them, they cost $6 each...min order ten with $10 p+p
I doubt these are the people you are looking for but they may be acceptable should you be unable to locate anyone closer to home.
Lynda

From: Andy
To: Orchid Talk List
Subject: Re: [OrchidTalk] two questions about virus
Date: Sat, 24 Apr 2010 21:50

I would suspect this is virus − is there anything that connects all these plants? Repotting, pests ? There is a virus called aucuba mosaic virus − don't know if it has anything to do with this but the leaves look very like aucuba!

Anyway best of luck with it. This is a test site: http://www.pocketdiagnostic.com/

From: Tricia Garner
To: Orchid Talk List
Subject: Re: two questions about virus
Date: Sun, 25 Apr 2010 09:25

I take it you have ruled out false spider mite damage? That was my
first thought on seeing the pics.

From: Roger Grier
To: Orchid Talk List
Subject: PLant problems.
Date: Sun, 25 Apr 2010 09:50

Geoff, I know what you are thinking as I have had similar strange markings on some of my plants over the years. And as to the 'experts' not knowing what it was, reinforces my statement [nothing cynical meant] that the word 'expert' should never be used.......maybe 'experienced' should be used.

Anyhow, I doubt if we will ever know. I do have that little booklet all about virus and whatever, but in all honesty these things do crop up, and we all try so hard to find out the answer, but it normally does not come.

I look at your second photo and see lovely green leaves to the left.........same plant, or another plant? If it is another plant then maybe the affected ones will get your attention for some time to see what happens. I hope that they grow out of the strange markings.

This Winter was very cold and DARK and prolonged. Whether that had something to do with it we will never know. I have lost many of my Cattleya type orchids, and for some weeks I was a bit downhearted and puzzled. Especially as some that are alright have just started to show new growth.

I am quite certain that the problem has been rhizome rot.......why? I do not have a clue, but we will soldier on.

From: David Martin
To: Orchid Talk List
Subject: Re: [OrchidTalk] two questions about virus
Date: Sun, 25 Apr 2010 15:30

Hello Geoff,
As we are all very careful to stop the spread of viruses in our collections my personal opinion is that it probably looks like insect bites causing the chlorosis especially as a number of your plants are affected.
Paul mentioned cercospora and septoria which are also possible causes.
Are there any signs of necrosis on the undersides of the leaves where the puncture points might be?
It's rather strange that the plants are evenly covered all over with the spots. Would virus suddenly appear like that or would it spread gradually through the plant from the point of inoculation?
David

From: Dennis Read
To: Orchid Talk List
Subject: Re: [OrchidTalk] two questions about virus
Date: Sun, 25 Apr 2010 15:35

Geoff, Two wears ago I had a similar marking on some Lycaste leaves. I eventially put it down to a strong mix of pesticide (provado) or that mites or thrips had taken a bite and died. Either way as Lycastes are deciduous the leaves died and next year all was well.

From: Geoffrey Hands
To: Orchid Talk List
Subject: Re: [OrchidTalk] two questions about virus
Date: Sun, 25 Apr 2010 21:00

BTW it was on my one and only Lycaste campbelli which had two leaves. I cut them off too , and repotted as well. It has a new growth , so we will see .

From: Geoffrey Hands
To: Orchid Talk List
Subject: Re: [OrchidTalk] two questions about virus
Date: Sun, 25 Apr 2010 21:00

Last night I collected all the damaged plants together − I was surprised at
how few there were . I suppose that when they were distributed along the
bench they made it look as though there were far more than is the case. In
fact, it seems that several plants were keiki propogations of Dendrobium
Stardust "Clementine" − and several members here had some of those from me ,
and no-one else seems to be complaining ? .
Also a big D. Pearl Princess and a couple of propagations from it , and one
D Hawaian Giant. I cut off all the bad canes − the new growths on all of
these are clean at present, and put them all together away from the other
plants. The D. kingianums turned out to have damaged leaves which were
different, and more normal ( water spots, scorch, etc) − and since I have
lots of them, I simply threw them away.

I had a chat about this to one of the growers at Burnham, on a visit there
today, and whilst he did not have the plants to see, he thought that I had
done the right thing ; if the problem recurs I'll junk them ; if not, it was
a temporary problem from some cultural error, and I can sleep happy again.

Did I say, by the way, that I had stopped using my Jaybird humidifier
because I became convinced that the water spray was leading to spots on
cattleya and some other leaves ? I had not noticed this in the past, but
maybe the motor does not run as fast now ( it must be 10 years old) and
hence the atomisation of droplets may not be as good as it used to be − or
maybe it is the different water here ( it runs off mains ) . Perhaps this is
the same problem, but looking different on the dendrobes...

From: Tony Watkinson
To: Orchid Talk List
Subject: About virus
Date: Mon, 26 Apr 2010 05:50

The Capsicum virus has the effect on orchids of leaving yellowing patches on leaves. See the link below.

http://www.nchu.edu.tw/~add/budget/student%20abroad/inter-meeting-95/T95-2-04.pdf

From: Geoffrey Hands
To: Orchid Talk List
Subject: Re: [OrchidTalk] About virus
Date: Mon, 26 Apr 2010 11:50

I think that this is it. And although I am that much further forward, there
are still a few unknowns − like, has the virus ( assuming it is one )
entered the plant elsewhere than on those leaves, and if not it will not
re-appear now they have gone − but conversely − my action has not solved the
problem.

What is the vector I wonder − viruses have to be transmitted from cell
interior to cell interior, so it has to be a sap-sucker,

I thought − in fact I have said − that I don't have false spider mite, but I
just went and checked on the apparently good leaves of the plants , where I
had cut canes off ; my eyes are not good enough to see the beasts unless
present in large numbers, but the old wipe with moist cotton wool test is a
good one, I believe. If the cotton wool looks stained reddish brown − they
are there. And yes, D Hawaian Giant is infected; it is now in the rubbish
bin. The others not, I think. But they will stay in isolation for the time
being.

So it came in with phallies ; all those are isolated, trying to grow them
better in more heat. I'll do the test on them − few are good enough to be
worth trying to keep if suspect in any way. The suggestion aired here
recently − throw them all away , buy good ones occasionally and keep them as
strictly house plants , seems better and better !

From: Dennis Read
To: Orchid Talk List
Subject: Re: [OrchidTalk] About virus
Date: Mon, 26 Apr 2010 16:45

Geoff, I cannot see the reason for binning a plant if it is infected with mites. A drench with methylated spirits keeping wet for 15 minutes then wash off with water wiil kill any pest. They also die happy stoned out of their tiny minds so keeping the Islington Pest Huggers happy.
Dennid
PS. I have run out of rain water in Devon IN April !

[...]
> I thought − in fact I have said that I don t have false spider
> mite, but I just went and checked on the apparently good leaves of
> the plants , where I had cut canes off ; my eyes are not good
> enough to see the beasts unless present in large numbers, but the
> old wipe with moist cotton wool test is a good one, I believe. If
> the cotton wool looks stained reddish brown they are there. And
> yes, D Hawaian Giant is infected; it is now in the rubbish bin. The
> others not, I think. But they will stay in isolation for the time
> being.
[..]
----------------------------------------

From: Geoffrey Hands
To: Orchid Talk List
Subject: Re: [OrchidTalk] About virus
Date: Mon, 26 Apr 2010 18:50

No, the point is Denis, to bin the plant with virus , in fact, on further thought, all of them showing the virus symptoms even if the known virused bits have been cut off.

I found a couple of Acinetas virused too , this pm. Since these are plants I keep in the hope that one day I will flower one its no hardship to put two in the bin. Better that than a mostly virused collection !

From: Tricia Garner
To: Orchid Talk List
Subject: [OrchidTalk] Re: About virus
Date: Mon, 26 Apr 2010 22:15

Geoff, how did you find out so quickly that they are definitely
virused? You must have some serious connections!

On 26 April Geoffrey Hands wrote:
> No, the point is Denis, to bin the plant with virus , in fact, on
> further thought, all of them showing the virus symptoms – even if
> the known virused bits have been cut off.

> I found a couple of Acinetas virused too , this pm. Since these are
> plants I keep in the hope that one day I will flower one – its no
> hardship to put two in the bin. Better that than a mostly virused
> collection !
>
> Geoff

From: Alan Garner
To: Orchid Talk List
Subject: [OrchidTalk] Re: About virus
Date: Tue, 27 Apr 2010 09:50

I cannot resist adding to the thread about viruses by asking why we,
so often, assume that something different about our plants is the
result of a viral infection when it is much more likely to be the
result of some deficiency in our cultural regime. I doubt that many
of us has actually seen an incontrovertible example of a virus and
even fewer of us has had an example in our greenhouse!

Of course we should be alert but not to the extent of frightening new
growers or inexperienced growers by suggesting that every blemish is
the result of a viral infection and therefore their much loved plants
should be destroyed. Trying to identify viruses via photographs in
books and photographs on web sites is, I would suggest, at least a
futile exercise and at best only a vague indication. Professional
suppliers to the public have every right to be particularly careful
but I suspect that the methodology available to them should mean that
they make fewer mistakes.

From: Dennis Read
To: Orchid Talk List
Subject: Re: [OrchidTalk] Re: About virus
Date: Tue, 27 Apr 2010 13:35

Alan, I cannot but agree. It remands me that about 10/12 years ago a member of tha NHOS sent leaf samples to many experienced orchid growers/nurseries. If I remember correctly the answers split into four definite ailments only one of which was virus.
The only way I believe is to send a sample to a respecfed lab and pay the money
Regards

From: Geoffrey Hands
To: Orchid Talk List
Subject: Re: [OrchidTalk] Re: About virus
Date: Tue, 27 Apr 2010 16:20

You know what they say Tricia ? If it walks like a duck, squauks like a
duck......

I went to the web-site suggested by Tony , read all about it, looked at the
pictures and the description − went and looked again at my own pics
including some I didn't send, and then went and looked at my phallies too -
which I had left out the reckoning previously. I reckon I am far more than
50% certain − maybe 80 or 90% certain that I've got the capsicum virus,
passed on from Taiwan phallies.

The virus tester is I think about £15 for a one shot ( one plant) kit ;
don't know how accurate it is or easy to use. But it is just uneconomic on
small plants ; even my big D.Pearl Princess − maybe six new growths, a dozen
leafy old canes − sure, if the kit says it is not virused, fine − but I
still couldn't show the plant or do much with it until it has grown a new
set of canes ; I have small props of it − which are currently clean. I'll
grow them on.

I have somewhere approaching 2000 plants ; destroying a dozen for the sake
of the rest seems more sense than taking a gamble !

> Geoff, how did you find out so quickly that they are definitely
> virused? You must have some serious connections!

> > No, the point is Denis, to bin the plant with virus , in fact, on
> > further thought, all of them showing the virus symptoms – even if
> > the known virused bits have been cut off.

From: John J. Rupp
To: Orchid Talk List
Subject: Re: [OrchidTalk] two questions about virus
Date: Tue, 27 Apr 2010 19:35

I am a bit late in getting into this thread due to time and other
commitment constraints, but thought I would jump in anyway. I have some
time as it is currently 33 F, and snowing with several inches predicted
for my area by tomorrow afternoon. Yesterday it wa 67 F and I was
painting the house.

Ok, back n target. A couple years ago, I had several plants, phal and
cattleya as I recall, that looked just liked Geoff's pictures when I
brought them in after their summer outside. I just assumed that it was
due to insects even though I could not see any critters at all. I
sprayed, soaked, them with every insecticide and fungicide I had, one at
a time, with a few days between applications. I figured that with this
chemical overload, I would either kill whatever was attacking the plants
or the plants. All survived, and the new growth was normal. It was fun
watching the new leaf on the phal grow out with the speckled front half
and the smooth green rest of the leaf.

At least in my case, I am sure it was not a virus, which is good as I
never once gave it a thought.

From: Geoffrey Hands
To: Orchid Talk List
Subject: Re: [OrchidTalk] Re: About virus
Date: Tue, 27 Apr 2010 19:40

In this particular instance Alan , I have ( with one exception) many
examples of the same plant, or of others which are genetically very similar
, all grown in the same conditions, side-by-side, so if just a few look
remarkably different − not slightly different , but remarkably so , then the
usual answer of deficiency in the culture is extremely unlikely to be true.
E.g the Acinetas I mentioned last − I have about 12 , composed of several
different species. The ones I have chucked out are D.superba and
D.antiquoiensis − and I have at least one further example of each of these
. All my Acinetas − bar the two mentioned, have perfect foliage. All hang up
together on the same rail, etc.
Of course the others may develop leaf blemishes in the course of time and
prove that all are virused, or none are and it is indeed bad culture ; but
if they don't − then I have done the right thing. And if I wait, and if it
is virus, then waiting may have allowed time for infection...

( I think all these questions/alternatives/decisions could be reduced to a
mathematical formula -( it might be interesting to try) ; if the answer,
rounded to the nearest whole number is above X, then destroy , if below,
then don't − an idea to pursue if I am marooned on a desert island with a
computer, a few maybe virused plants, and a year or so to wait to be
rescued....

From: Geoffrey Hands
To: Orchid Talk List
Subject: does anyone else grow (hardy) cyprepediums in the garden ?
Date: Tue, 27 Apr 2010 20:55

After my success with my first plants − increasing nicely for a few years, I
splashed out and bought two more hybrids, several plants of each, at a
horrid price .

But so far this year nothing is showing above ground from any of them − the
established plants or the new ones.

They are supposed to be hardy , even needing the chill. And whilst it was
the worst winter for 31 years − they say − we never had any snow, down here
on the south coast , and although we had frosts on a lot of nights, the
lowest temperature shown on my instruments just before dawn was minus 4 C.
Not enough to worry them, I should have thought.

Maybe I am too impatient and they will show up above ground next month − but
it would be re-assuring − or otherwise − to hear reports from others ?

From: Tricia Garner
To: Orchid Talk List
Subject: Re: [OrchidTalk] Re: About virus
Date: Tue, 27 Apr 2010 22:35

With regard to phals, I had a problem with most of mine a couple of
years ago and couldn't work out what was damaging the leaves. The
subsequent new leaves were (and still are, thankfully) clean so I was
reluctant to blame virus. It was solved when I attended a talk on
pests and diseases by Laurence Hobbs where he showed a phal leaf
which had been attacked by false spider mite − it was identical in
every way to the damage on my plants. The point being I was able to
see a leaf to compare, rather than a picture, so I maintain that when
you say 'known virused bits' what you really mean is 'suspected
virused bits' :-)

I'm not saying you shouldn't bin your plants if that makes you more
comfortable, but I suspect many a plant which isn't virused has ended
up on the compost heap.

> You know what they say Tricia ? If it walks like a duck, squauks
> like a duck......

From: Geoffrey Hands
To: Orchid Talk List
Subject: Re: [OrchidTalk] Re: About virus
Date: Wed, 28 Apr 2010 08:50

You can see now why the orchid trade love me. My solution is the best one -
they must say.....

From: Dennis Read
To: Orchid Talk List
Subject: Orchid Show
Date: Wed, 28 Apr 2010 16:35

For those who live near the West Coutry, The Devon Orchid Soc. Is holding its Annual show At The Elizabeth Hall Exmouth rhis coming Saturday !st May.
Regards

From: Dennis Read
To: Orchid Talk List
Subject: Terrestrials
Date: Wed, 28 Apr 2010 16:45

This months RHS magazine -The Garden- has a six page spread on Terrestrial Orchids. A 'well worth it' article.
Also Burnham's are hosting a Terrestrial Orchid week-end 8/9 May at their nursery by Laneside nurseries . There will be talks, a show table and plants for sale.
Regards

From: Roger Grier
To: Orchid Talk List
Subject: The Garden RHS Magazine.
Date: Wed, 28 Apr 2010 17:15

My ears pricked up when I read what you said about the magazine and the Show at Burnham's. As I do not get that magazine, can you please tell me more about it, and possibly scan what you think might interest me and other like members.

One interesting thing to tell you............because the last Winter was so long and cold, there is hardly any new grass in the New Forest, and the heather shows no young shoots. The areas that people call 'moor' look very sad. So, what do the ponies eat......yes, the bloody orchids.

By the way, at long last I have given up on growing 'Greenhouse Orchids'. I will not be buying any more, and will just keep what I have. Most probably get rid of what is left by the end of this year.

From: Roger Grier
To: Orchid Talk List
Subject: Re: [OrchidTalk] does anyone else grow (hardy) cyprepediums in the garden ?
Date: Wed, 28 Apr 2010 17:20

I don't grow Cyps, but I do have some of our own terrestrial orchids in my garden. All of them are showing above ground, even, and I must admit that I am a bit surprised, a few shoots showing on Helleborines.

Mind you, out in the Forest I still am waiting for some to show, so let's hope that your Cyps will show in the next week or two.

From:
To: Orchid Talk List
Subject: Re: [OrchidTalk] Re: About virus
Date: Wed, 28 Apr 2010 17:30

Geoff,
I am inclined to agree with you, particularly with regard to relatively
common hybrids. Dump them, with their diseases and pests, and get a fresh
specimen. Not only would this help keep the other plants clean, but also
helps support the economy, your favorite plant dealers, and increases
demand for mass produced virus-laden merchandise plants. And the cycle
repeats.

On the virus matter, however, I am not yet convinced that all incidents
are worth worrying about. Most known orchid viruses are either not easily
transmitted by anything other than the sloppiest techniques of trimming or
propagation, or are embedded into plant populations by unconcerned bigtime
cloners of throwaway plants. Although aphids, trips, leafhoppers, and a
few other insects are demonstrated to vector viruses in other plants,
there really is very little objective assessment or demonstration of this
in orchids. This makes me wonder how much hype is developed using the
premise that most people become irrational about pests and disease. And
then there is the issue based on scientific evaluations that most, if not
all, organisms have multiple viral parasites that simply remain
unrecognized due to the lack of symptoms, and are normally not lethal. I
recall reading about this with regard to plant viruses and that infected
plants would not show symptoms except under specific environmental
conditions. Such conditions would include such things as suboptimal
temperatures, nutrient sources, lighting, etc., or even genetic weakening
from excessive inbreeding and cloning. Further, that activation of a
virus, or the plant expressing symptoms of a virus, with regard to such
environmental factors would often be a delayed response.

Anyway, until the saga of the orchid viruses is better written, I remain
inclined to toss or not worry.

From: Mark Macklam
To: Orchid Talk List
Subject: Re: [OrchidTalk] does anyone else grow (hardy) cyprepediums in the garden ?
Date: Wed, 28 Apr 2010 19:30

To give a sense of place, I'm writing from Edmonton, Alberta, Canada. Same latitude as Huddersfield, but about 2200 feet elevation. Cold winters [-5 to10 celsius average, about]. I do not grow any plants myself, do not have a good location. However a few members of our society grow quite successfully several plants. Many long lived. Mostly they're left to there own devices and left to rely on snow cover only as a winter insulator. Here they will not be up for some time, say early May [maybe not this year given the current soil temp and weather] but will be in full flower usually my mid-June, often June 16 is for some reason the day they start.
Very expensive here, too.
Look forward to your photos.

From: Dennis Read
To: Orchid Talk List
Subject: Re: [OrchidTalk] The Garden RHS Magazine.
Date: Thu, 29 Apr 2010 08:35

Roger, the magazine is on sale in newsagents but I can scan it if needed
Regards

From: johnstanley
To: Orchid Talk List
Subject: Re: [OrchidTalk] Re: About virus
Date: Thu, 29 Apr 2010 11:15

Although there are viruses we could well do without, I wonder how many
organisms (plant or animal) are really free of viruses (and bacteria for
that matter). I suspect I'm not short of a few passengers of their ilk and,
frankly, I'm not ready for dumping yet (according to me of course)!
Cheers
John

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2010 Archived Messages

April 22—30