On the questions about virus: I have been virus testing. I have a few pictures of the virus symptoms on my pbase site. http://www.pbase.com/schnitz/virus_in_orchids There is no guarantee that the symptoms seen there are any kind of surefire indication of virus, or are even related at all to the virus. Just pictures of how the plant looked around the time the plant tested positive to virus. This site will be updated in a couple of weeks with a few more pictures.
Some of my observations are: Paphs do get virus. Two out of the three Paphs tested were positive for CMV. These were around for many years. Of 200+ tests so far for CMV and ORSV, about a 1/3 of the plants were positive for virus. Probably is high because the worst plants were tested first. Cattleyas get both CMV and ORSV, as do Laelias, Epidendrums, and others related. Many recently purchased plants from big time orchid nurseries were virused. The responses from the nurseries were mixed. Some virused plants showed no symptoms. Some plants that looked bad, tested negatively to CMV and ORSV. It is still possible that other viruses are present. If someone could direct me to a lab that tests for viruses other than CMV, ORSV, and BYMV, I would appreciate the lead. A variety of the worst looking non-pleurothalid plants, but negatively testing for CMV and ORSV, were sent for BYMV testing, and all came back negative. I have had two false negative results with green house screening, and now use the Double Well tests (Critter Creek). Since the removal of all these poorly growing plants, growing orchids is fun again. Cynthia, Prescott, AZ >> Recently, on a different forum, a person showed pictures of orchids he >> suspected of harboring >> virus. Of course no one can tell from a picture whether a plant is >> virused or not.It should be >> tested.I was about to recommend to the person showing the pictures that >> he get his plants >> tested when I realizedthat I wouldn't know what the test results would >> mean.Anyone interested >> in talking about viruses? >> >> I wondered about how we judge 'by sight' if a plant has a virus.I know >> about color break in a >> bloom.I know about a trapeziodal mark on a leaf of a cymbidium.I know >> about longitudinal >> streaks in a leaf. >> >> Of these 3 the only one I believe to be pathognomonic is the trapezoidal >> mark on a cymbidium >> leaf. Color break can come from a variety of sources, heat, pesticides >> are two that come to >> mind. Streaked leaves from heat or other poor culture. >> >> In the back of my mind I recall that old cut-flower houses didn't really >> care about virused plants >> as long as the virus didn't affect the bloom,therefore thereare several >> viruses >> housedinorchids, but since they don't affect the blooms they aren't >> considered a problem. Also >> in the back of my mind I recall that labs only test for a few viruses and >> you have to know which is >> virus a problem for your plant; like should you care aboutodont ring spot >> or cymbidium virus if >> you only grow cattleyas? Which brings up another possible myth: not all >> orchids are 'susceptible' >> to virus (Paphs aren't?? something like that.) >> >> Any information would be a help. Obviously I've got a lot to learn >> >> K Barrett >> N Calif, USA _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
