Viruses in bulbs

michaelcmace@gmail.com michaelcmace@gmail.com
Sun, 10 Nov 2019 10:50:30 PST
Ahhhh, viruses again.

I want to make a comment, but let me start this by saying that I am not
about to criticize ANYONE on the list, or anything that was just posted.
It's all good stuff, and we are all trying to help. But I want to talk about
a pattern we've all fallen into and see if we can improve it.

Here's what tends to happen when the the subject of viruses comes up on the
list:
--Somebody posts a picture of an affected leaf
--Someone says it looks infected
--Someone says it looks like environmental or insect damage
--Someone then suggests that the grower get a virus test
--Someone suggests that the grower destroy those plants
--Someone suggests that the grower share only seeds

The grower is left frightened and unsure about what to do. 

Rinse and repeat a year later.

I think we can do a little better. First, Nhu and Jacob and other PBS
members compiled a very extensive page on the wiki about bulb-related
viruses, leaf pictures, and what to do. The link is below, and anytime the
subject comes up we should remind folks that it's there:

https://pacificbulbsociety.org/pbswiki/index.php/…

However, even with that guide, it's still pretty hard be sure if you have
viruses and what to do about them. It's especially difficult because
(according to what I've read) leaf damage from stress really can look a lot
like virus damage, and some viruses in some conditions won't do any leaf
damage at all. So you can't ever really be sure.

I'd like to ask if we list members could collect some more info to add to
the wiki page:

--What are the best / most affordable places to get virus testing? We have a
directory of seed suppliers; how about an informal directory of virus
testing suppliers? If people want to post links to the testing services they
use, I'd be glad to put that in the wiki.

--Can we give a list of which viruses a grower should test for? The wiki
page lists a bewildering array of viruses, and when I looked for virus tests
online, they all seem to charge per virus. So you have to ask specifically
which virus you want to test for. I don't know about you, but I would not
have a clue what to test for if I had a questionable leaf. Could we compile
a table that cross references genera and the viruses to test for? I'd be
glad to help build that if folks on the list can provide the info.

--Can we also compile info on treatments for viruses? There's some
literature online that talks about commercial heat treatment for bulbs and
corms that have viruses (it's apparently done for some commercial genera
like Freesia). Supposedly there is a magic temperature range where you can
get them hot enough to inactivate the virus but not hot enough to kill the
bulb. You might think there's no way an amateur grower could do something
precise like that, but actually if you have a sous vide cooker, it's now
very easy to hold something at an exact temperature for hours or even a day.
It would be great to know if that could work for bulbs or seeds.

--I ask about virus treatment because it seems to me that there's an
increasing amount of literature saying that some plant viruses can be spread
through seeds. For example, it's just been made illegal to import pepper and
tomato seeds into the US without a phyto, due to viruses in seeds. We all
tend to treat seed propagation as the magic firewall that will prevent
viruses from spreading from grower to grower. If we suddenly discovered that
the firewall leaks more than we thought, we could end up with import
restrictions or even rules against sharing seeds within a country. If we get
ahead of that issue, we'll all be more worry-free in the future.

So my questions to the list are:

--If you've ever done virus testing, which service(s) did you use and what
did it cost?

--Can anyone give information on which viruses are most common for a
particular genus, or suggestions on how to know which viruses we should test
for if we suspect we have an infection? (That info is most important for
amaryllids, since they get asked about the most often on the list.)

--Does anyone with more botanical knowledge than me know if there really is
an increase in reports of seed-transmitted viruses? Should we be worrying
about that? (It's easy to scare yourself from the info online, as is true of
any disease-related info on the web.)

--Does anyone have knowledge of heat treatment (or other treatments) for
plant viruses? I'd be willing to do some experiments with a sous vide cooker
to see if I could heat-treat seeds or bulbs without killing them, but I need
to know the temperature and number of hours required.

Any thoughts?

Thanks,

Mike

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