do you worry about virus?

[Ordphien]

I think I'll practice good hygiene with my growing collection off minis as much as possible.
But unfortunately the water sharing thing I can't budge on.

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[samarak]

Diagnosing virus by appearance seems to be very hit or miss. There is a discussion going on right now, in another forum I'm on, about viruses in bulbs. Several people there have told stories of submitting samples to labs, at considerable expense, and finding out that bulbs they thought were virused (based on appearance) were not, and that others they thought were clean were virused.

I've had people tell me that leaf damage or discoloration that I knew to be from sunburn or cold damage was a sign of virus. Some of them are so afraid of virus that they'll throw out perfectly healthy plants just on the suggestion from someone, anyone, that they're virused.

Personally, if I see color streaking or "color breaks" in the flowers of an orchid, I immediately think virus. Otherwise, unless a plant seems in general to be in poor health, with even new growth showing damage with no apparent cause, I don't worry much. (If I were given a division of an old cymbidium or cattleya clone, I'd certainly test it, since I have test strips around.)

Even streaking or color breaks on flowers isn't certain, though. We have a seedling from another grower that showed some streaking in the flower on first bloom, and I immediately quarantined and tested the plant (even though seedlings, in general, are low risk for virus). The test was negative. Since then, I've retested with another strip from a different batch, and again negative.

Steve

[Orchid Whisperer]

Steve, where do you get your test strips?

[Sharry]

Thanks for the info, Steve.

I did test all my orchids because I have some that I inherited from my mom. Since they tested negative I want to keep them that way. Most of the positive plant had symptoms had blotchy streaky leaves and one Phal seedling that would just not grow. The rest were mericlones. None of the species ever tested positive. So now I just test mericlones.

If a person has the space, it never hurts to keep new plants separated for awhile and inspect them often for scale insects and other minivarmints or disease symptoms.

[samarak]

Originally Posted by Orchid Whisperer

Steve, where do you get your test strips?

I bought them from Agdia - they make a combination strip for cymbidium mosaic virus (CymMV) and odontoglossum ringspot virus (ORSV) designed for people like us (i.e., easy to use, and available in less than industrial quantities - 5-pack or 25-pack). Here's a link to the 25-pack:

https://orders.agdia.com/InventoryD....ribute_Size=25

I don't totally 100% trust them, just because I don't have the necessary data, but I would certainly take any positive result very seriously, and would immediately at least quarantine the plant pending retesting with a strip from a different batch (or, if it wasn't a plant of value, just dispose of it).

Steve

[littlefrog]

I have seen several reports that soaking your tools in milk (freshly rehydrated powdered milk will work) is an effective way at inhibiting virus transmission. Obviously you want to make a new solution every day...

On a practical note, I assume everything is virused and act accordingly. I'm not compulsive about it, but I'm cautious. And I discard anything that looks virused.

[lepetitmartien]

Rob, have you some links to follow in this?

[Vanda lover]

Originally Posted by AnonYMouse

I don't actively worry, I don't test. I DO practice good hygiene.

I'm with you on that one.

[littlefrog]

My memory is leaky as it is... The milk thing was from a few years ago. I do know we used milk a lot when I worked with antibodies, it generally binds to everything so it decreases the background noise. I was skeptical, but after thinking about it for a while, my thought at the time was that milk would bind to viral coat proteins and block the virus from interacting with cells.

I did just find this paper (it is somebody's thesis, not peer reviewed as far as I can tell). https://kb.osu.edu/dspace/bitstream/...NDA_THESIS.pdf. I'm really supposed to be doing my taxes or I would research it further.

[samarak]

Here's a link to a paper that trialed a number of things, including a 20% solution of non-fat dry milk, for ability to control tobacco mosaic virus on tools:

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(The title looks funny here, the forum apparently couldn't get the title, but the link appears to be good. The paper is open access, no subscription is required.)

They tested non-fat dry milk solutions, rather than whole or skim milk directly, and found it very effective.

However, there's also a comment that spraying with whole or skim milk is recommended to prevent the plant to plant transmission of TMV prior to handling tobacco plants, but wasn't effective against cymbidium mosaic virus in orchids. I haven't had time to follow up the reference.

Steve