Crinum viruses

Joe Shaw
Tue, 22 Aug 2006 17:13:31 PDT
Hi Gang,

Two or three years ago there was a nice bit of discussion about Crinum 
viruses, here at the PBS.  I remember doing some research on the matter and 
since that time I've been thinking about Crinum viruses.

In the past few months I have written to multiple colleagues on several 
continents, and I'll be writing up that information soon.  But the really 
amazing thing is that there is almost no scientific information, at least 
little published in recent decades.  There are 2 possible viruses that might 
cause mosaic on Crinum, Hippeastrum Mosaic Virus (HiMV), and Crinum Mosaic 
Virus (CriMV).  It seems possible that the 2 viruses are very closely 
related, or even the same virus, but perhaps not (no data).

No other virus type has been described (ever) for Crinum.  Thus, 
yellowing-type viruses, or necrotic lesion-causing viruses, etc., have not 
been described.  Of course, Crinum are not a big "crop" for the 
horticultural trade and it is possible that many viruses remain undiscovered 
merely because no one has bothered looking.  In other words, government 
Plant Health Departments, or individual professors, or other researchers, 
may choose to research problems that are more immediately related to global 
food production, etc.

The 2 viruses that have been mentioned are potyviruses (named after potato 
virus Y, a well studied member of the group).  Generally, potyviruses are 
transmitted by aphids or by "mechanical means."  Mechanical transmission 
means (to me) that if you use shears to cut one plant (leaves or bulbs), and 
the same shears to immediately cut another plant, that transmission may 
occur.  In contrast, mechanical transmission typically does not happen by 
leaf-to-leaf toucing in garden.  Thus, leaves from 2 plants that blow around 
in the wind, and which may have tearing or rips, don't seem to transmit the 
virus to each other.

I hope to put images up soon, which I think are caused by insect damage, 
pesticide damage, mosaic viruses, heat stress, fungi, etc.

For my own part, unless I find out about a new type of virus, I assume that 
all I have to deal with is a mosaic-causing virus that is transmitted by 
cutting tools or aphids (not sure of the species).  I have kept a few 
possibly-virused plants on one side of my yard, but have kept them 
over-treated with systemic insecticide so that (I suppose) any aphid will no 
have a chance to infect plants 100-200 feet away.

Additionally, I have placed some possibly virus-infected plants near healthy 
plants of different types.  I'm waiting for more time to pass, but in the 
past 18 months no mosaic symptoms have shown up on the healthy plants next 
to plants with mosaic.  Sometimes it can take years for virus symptoms to 
show up (not often, but sometimes).  I think gravepine cuttings imported 
from Europe into the USA require a 5+ year quarantine just to "make sure" 
they are clean.


Conroe TX
Rain may be on the way (about time),  lots of thunder and lightning, and my 
little dog is is hiding from the noise. 

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