Harvey -- wow, $2000 per variety! You must be really dedicated to figs to consider spending that much! Are you growing figs on a commercial scale now? I agree with your last point especially: the whole problem with any of this stuff about cleaning up FMV is the problem of reinfection. So instead of focusing on how to get rid of those nasty viruses, instead I put my efforts into helping the trees stay as healthy as they can be with respect to the other aspects of basic care. That's easier to address, and seems reasonably effective for the most part. My impressions are that in general, the symptoms and negative impacts from FMV are reduced in trees that are well cared for and free from other health problems. Granted, overall tree health involves a complicated dynamic (FMV probably weakens their ability to fight off other pathogens?), but regardless, basic care of the trees seems reasonably effective at allowing most trees to be productive and reasonably healthy despite FMV. Your Yellow Long Neck story sounds great.
But especially when you mention some varieties lacking vigor and speak of several strains of FMV (i.e. different combinations of the various viruses that cause "FMV" or "FMD"), that hits home with me. I've seen similar things (trees showing few or no symptoms, despite being surrounded by trees with more severe symptoms). Yet at the same time other trees that appear relatively clean become symptomatic when surrounded by the same trees. I suspect it's as you described -- I think it's likely that some of my trees have different combinations of the viruses. But why wouldn't they all get infected with all of the viruses that any of them has? I don't know. Maybe the really are all infected with the same sets of different viruses, but some of them are just better able to "fight off the effects". More resistant or better able to appear healthy and show only milder symptoms. All of that might be what's going on, whether because of differences in fig varieties or just differences in individual trees. But it also might be that some of the trees are infected with different cocktails of the multiple viruses. If that's so, then why would some of the viruses spread from tree to tree, while others wouldn't? IF that's the case (a big if), then it could suggest there are different vectors for different of the eight (or more) viruses involved. For what it's worth, that mystery is what fuels my interest in understanding the way these viruses spread, and whether the vectors are the same for each of the viruses. I suspect not, but it's just a suspicion and I'm not willing to spend much money to find out. Better resistance among individual trees (or among different varieties) seems equally likely as an explanation of what I see with these trees. If you actually do any of that "cleaning" stuff, whatever your experience is afterward would be fascinating to hear about!
Pete -- I didn't mean to sound personally argumentative in post #22. Sure I expressed some mild disagreement about a subtle point, but I thought I was doing it politely and respectfully. I really don't see it as argument in any personal sense, and feel no personal angst toward you (actually I think of you as a "fig friend"... my family sometimes chuckles about me spending time with my fig friends). Disagreement isn't inherently bad, is it? (I guess disagreement is inherently "disagreeable" though... lol). Anyway I tried sending an email but couldn't find a way to get that message to you privately. Peace.
Ed -- sorry if any of this looks like hijacking your thread. Maybe I'll go back into the woodwork for awhile now.
Mike central NY state, zone 5a