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06-11-2020, 11:45 PM
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Senior Member
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Join Date: Jul 2018
Zone: 7a
Location: Lower Hudson Valley
Posts: 496
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I just sent Critter Creek an email asking for tests and if they can test for OFV too. I don’t have a good feeling about this.
If it is in fact a virus (which I’m not optimistic that it isn’t based on the pattern), what’s the likelihood it could have infected dozens of other plants?
I’ve never used a cutting tool on these but there does tend to be a fair amount of splashing water and insects in my greenhouse.
I’m wondering if the person who had these last was a smoker as apparently Tobacco Virus can infect orchids and looks like this.
They are Coelogyne unchained melodies that originally came from a pretty reputable vendor. Would someone in my society have been careless enough to put a virused plant on the raffle table? Maybe that’s how they chose to get rid of it from their collection.
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06-12-2020, 12:11 AM
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Super Moderator
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Join Date: Jun 2008
Zone: 10a
Location: Coastal southern California, USA
Posts: 13,749
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Virus spread has lots of unknowns. Cutting with an unsterilized tool pretty definitely can spread it. Splashing? Less likely, not zero. Some sucking insects, not others. A member of one of my orchid societies (who is a biologist by trade, so applying his professional skills) has been very intrigued by this - has tracked it within his own collection. He set up an experiment with a batch of seedlings, to try to infect them on purpose. And after several years, they're all still negative. So... what we don't know exceeds what we do know. And nobody can tell just by looking... this was another one of his experiments, with photos shown to very knowledgeable people - nobody did better than "chance" for both positives and negatives.
All we can do is act as though every plant is potentially infected, and utilize good hygiene practices all the time. While most people are ethical enough to not put a known virused plant on a society raffle or sales table, there are exceptions... and people may just not know. I have seen some pretty bad-looking plants (not necessarily virused, but definitely not healthy) donated. There is one rather large club to which I belong, for which I no longer buy raffle tickets. Along with the good stuff, there's too much garbage on the raffle table. As my collection has grown, I have gotten a lot pickier about what I want to take home.
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06-12-2020, 12:13 AM
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Senior Member
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Join Date: Dec 2018
Location: Australia, North Queensland
Posts: 5,214
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Brassa ----- don't worry too much. I don't know how viruses work or how long they can hang on for ----- but if they don't penetrate a cut or wound etc, then your other orchids will probably be just fine.
And - even now - we don't know for sure what it is. The other thing is ----- another test is --- if you had been giving gentle air-flow for all this time of growing already ------ then that would be about the only cause for concern for me ... about virus that is.
That's because if for a long time we do our best to provide conditions that cut down on chances of fungus/bacteria etc, then seeing something like this could then spell more chance for virus.
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06-12-2020, 04:24 AM
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Senior Member
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Join Date: Jul 2018
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These particular plants had been in a prime spot directly in the path of and close to the heater/fan so they did get good air movement. That said, I don’t what what conditions they had before I had them.
They had the spots on them when I got them at the raffle table and I just should not have selected them with such spots. I did really want an unchained melody which I wasn’t able to find for sale at the time so I thought I had really scored at the time.
Now I’m rethinking if seeing them there was such good luck.
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06-19-2020, 11:10 PM
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Senior Member
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Join Date: Jul 2018
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Virus Results=Negative
I just tested one of these two and the results indicate neither CymMV nor ORSV. This result has rather surprised me.
That said, I did have some issues administering the test so it may be a false negative. I always bungle instructions in one way or another and I am not sure how precise I was or needed to be in following the instructions.
The result had only the control line and no other lines. I may test some more suspicious plants later.
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06-19-2020, 11:18 PM
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Super Moderator
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Join Date: Jun 2008
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Quote:
Originally Posted by BrassavolaStars
I just tested one of these two and the results indicate neither CymMV nor ORSV. This result has rather surprised me.
That said, I did have some issues administering the test so it may be a false negative. I always bungle instructions in one way or another and I am not sure how precise I was or needed to be in following the instructions.
The result had only the control line and no other lines. I may test some more suspicious plants later.
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Control line and no other line is an honest negative. What aspect of the instructions were you unsure about? Which test kit, Agdia or Riga? I'm guessing Agdia because you could probably get them faster...
Looking at the plants again, it is very possible that it's a bacterial or fungal infection. Virus is not all that common. I have had bad-looking plants test negative, and had some that didn't look horrid (but had something that triggered my attention, like color break on flowers) test positive.
Last edited by Roberta; 06-20-2020 at 12:09 AM..
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06-20-2020, 05:35 AM
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Senior Member
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Join Date: Jun 2012
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Location: SF Bay Area, CA
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Could it be rust fungus? Does rust happen on orchids? Because it looks like that on some other plants.
...but you used Physan...
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Anon Y Mouse
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I am not being argumentative. I am correcting you!
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Last edited by AnonYMouse; 06-20-2020 at 05:37 AM..
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06-20-2020, 12:15 PM
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Senior Member
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Join Date: Apr 2020
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Location: Upstate NY
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Brassa, I am by no means an expert on orchid diseases. I just want to share with you that I had a situation almost identical to yours. I was certain my orchid had a virus. I ran a test and could not believe the "negative" result. So much so that I tested it a second time and that was negative too.
I asked the board for help, and was advised to treat it as a fungal infection. I treated it with a copper fungicide, and a week later with a systemic fungicide. It's now one month later and I'm seeing lots of new growth with no spots. The whole orchid looks so much better.
My orchid is an oncidium. I don't know if these particular fungicides are safe or advisable for a coelogyne. Maybe the board can weigh in here.
Anyway, don't doubt your testing skills. I use Agdia strips. They are very reliable. The good news is that if it isn't a virus, it is treatable.
Last edited by MJG; 06-20-2020 at 05:21 PM..
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06-21-2020, 07:47 AM
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Senior Member
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Join Date: Jul 2012
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Location: Athens, Georgia, USA
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Notwithstanding the good advice already provided (regarding virus testing), I have had Cattleyas with serious root loss, followed by dehydration, that developed similar leaf spotting. Better growing conditions, better roots and hydration, spotting did not return on new healthy leaves. Bloomed fine after that.
In my case, I think it was an opportunistic fungus taking over leaves that were weakened. I'll admit that I didn't invest in virus testing.
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06-21-2020, 08:10 AM
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While in this situation ------ could probably line up a bunch of different systematic and non-systematic treatments -- and do some rotations, applying one at a time (and giving some time for each to do whatever it can). And watch for signs of improvement. But at the same time - providing good temperature range, and allow for some gentle air-movement around the isolated plant.
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