Hi Oliver. All testing so far has been with Critter Creek Labs. I, and sometimes with another person's samples added, started with the cheaper greenhouse screening, only to discover some obvious false negatives, so at some point, we changed over to the double well test. I retested some that I hoped would have been false positives, but no luck, they were still positive. Some statistics: 261 tests made on 234 different plants for CMV and ORSV, and another 10 for BYMV for some oddly acting plants just to see if this was something to be concerned about. Approximately 1/3 of the plants tested positive for one or more of the common viruses, but none for BYMV. The incidence was much higher for plants in my collection for a long time, and lower, but still substantial, for recently purchased plants
All four Vanilla plants, 2 planifolia, a pompona, and an unknown Mex. species, were positive for CMV, and the thin fast growing planifolia that I thought was a seedling, was also positive for ORSV. Of 14 reedstemmed Epis I brought with me from California 5 years ago, 1, an Epicatt, was negative, 7 were positive for both CMV and ORSV, 4 for ORSV only, and 2 for CMV only. But 2 of the ones listed as having both, had a second test (a different division of each) that tested positive only for CMV. ORSV may be an iffy test. One of the CMV plants was Epiphronitis Veitchii. I had an opportunity to test a couple of other clones of this hybrid (one of which may have been a long separated division of the same plant as mine), and both tested positive for CMV. Of the Reedstemmed plants purchased more recently, about half tested positive with results similar to the above. I have not tested anything in the last year, and hope to do my own testing in the future with a high power light microscope looking for viral inclusion bodies. I have all the equipment, the chemicals, the test plants (I am maintaining most of the virused plants in a bay window in my home), but not the time to delve into this new and very complex process. If anyone would like to look into this technique, you can look at the Oct '86 AOS bulletin, or check out this site: http://plantpath.ifas.ufl.edu/pdc/Inclusionpage/Howto.html But trust me, in this day and age, the chemicals are NOT easy to come by. The companies that sell them will not ship to a home address, only a business. And I am sure a very good microscope would be needed, as well as info from both of the sources above. Expect to spend a thousand for the microscope, and another for the chemicals and supplies. Cynthia, Prescott, AZ 9Date: Tue, 18 Dec 2007 12:26:53 +0000 From: Oliver Sparrow <[EMAIL PROTECTED]> Subject: Re: [OGD] virus testing To: [email protected] Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset=us-ascii Quote: "Schnitz" <[EMAIL PROTECTED]> >I will point out my recent observations re:virus and Vanilla. The last 4 Vanilla plants I bought tested positive for virus I would be interested to know which virus, and how you tested for it. (A single cubic centimetre of 'clean' water has around a billion virons in it, after all.) ______________________________ Oliver Sparrow +44 (0)1628 823187 www.chforum.org _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
