Dear Mary Sue:
You are wrong: not all panic at viruses. You can
still see remarks like “well, it has virus but I like it anyway” too often.
Fortunately there is a growing concern and you have growers like Diana, Dirk
Wallace and Dash Geoghegan that spend lots of time and money in taking every
precaution to sell healthy material. With time (and no doubt with more
valuable collections destroyed by viruses) people will learn that it is a
poor bargain to keep a diseased incurable plant against the rest of the
collection. We did not invent virus: it is a terrible occurrence that we can
encounter during our experience as bulb growers. Right now, before our very
noses, one of the most fantastic projects of our time, the assembling of a
huge Canna collection has been put to an end by this. Most of you know about
the National Collections scheme in England. Well, there was a fabulous
collection of them being assembled and the owner was very happy to have
found in France 52 cultivars most of which would prove new introductions (to
the 140 others he was already growing). BUT, in came the Trojan horse! Among
those plants from France some had a virus that rapidly spread to other so
far healthy ones. That virus was masked by the plants’ inherent vigor. When
the owner noticed the appearance of uncommon yellow mottling in many plants
had them tested and it gave bean yellow mosaic and Canna viruses. As a
result 70 cultivars (yes, 70!) had to be destroyed at once and the news were
that he had discontinued the project altogether. So remember this short tale
every time something shows symptoms and you decide to keep it. In my
experience in most cases this is a common plant that sooner or later you
could replace!
One can never overemphasize the need of a quarantine period . Do maintain
your newly introduced plants away from your collection for a time (two weeks
at last). Virus symptoms can be masked (there are symptomless and latent
viruses) but under periods of serious stress (like when you take a plant
from its “home” and take it somewhere else) symptoms can appear. They are
more visible (at times ONLY visible) in new growth so watch for the tips of
new leaves. If they are uniformly green you have many chances that the plant
is healthy. If it shows mottling in a different shade of green be very
worried. If you are not convinced do not let it close to your healthy
collection. For instance if you live in Halifax, send it to Vancouver for
safety!.
You are right in that there is so little in the web
on virus symptoms images. In the Ball Guides there are a few images of
viruses in Liliums, Agapanthus, Canna and in a number of dicots.
There is a lot of virused material in the trade and
several nurseries have a few cultivars of Crocosmia that are terribly
virused. Any comments Dave? In my opinion it was viruses who wiped out all
those fabulous Crocosmias you mentioned of late.
Regards
Alberto
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