Re Peter's comment that water collected in the leaf axils of my afflicted plants. Not the case, Peter, I have always been careful about that and never have water left on leaves at night. The loss of plants was due to something contagious enough to pass over some genera and infect others. I don't think it was my handling them as once plants are in place on the greenhouse bench, I rarely touch them. I thought it might have been "spores" or something spread by the fans. I don't think it was insect spread unless it might have been fungous gnats as there are always some of them that don't get caught by sticky strips around. There were no aphids at that time (autumn). The whole episode occurred very rapidly, within weeks, afflicting only certain genera. The experts in my area had no idea.
Unfortunately, I don't have a good location to quarantine plants. Len _______________________________________________ the OrchidGuide Digest (OGD) orchids@orchidguide.com http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com