"david weindel" <[EMAIL PROTECTED]> queried thusly:
> Hello all: The discussion on disinfectants brings up a question that I have
> been debating with myself. Without much resolution. To what extent are
> tropical rains like a disinfectant wash?
Not to get completely off the subject, but although I've wondered the same thing
myself, I wonder more about the ability of UV light (from sunlight) to reduce the
concentration of pathogens and spores on plants in the wild.
One would think that in culture, many plants are grown under glass or polycarbonate (I
don't think polyethylene blocks much UV, but I'd have to check), which remove much of
the UV intrinsically present in sunlight. I would suspect, but have no evidence, that
this difference may allow concentrations of pathogenic spores to be higher in
cultivation than in the wild.
"Gary Wills" <[EMAIL PROTECTED]> noted about Physan accordingly:
>I asked Tom about their claim of efficacy on TMV and the
>data they supplied was 30 years old. I asked about this and
>they said no follow-up studies have been done. At this
>point they are concentrating on expanding their market
>particularly into more profitable areas. I guess orchid
>growers just don't use enough of their product to make it
>worthwhile to update old studies with modern techniques. I
>shared this information with AJ Hicks at the time. So
>AJ, if you have something more to add here, please do so
>before I overstep the boundaries of what I know and
>inferences I shouldn't make.
You'd think in this day and age, to slap "virucide" on the bottle, you'd need data
that were a bit more robust than the substantiation offered up. Gary was good enough
to pass along the paper (which has gone missing on my hard drive despite efforts to
the contrary), which was:
1) Not peer-reviewed
2) Never followed up with publishing in a peer-reviewed journal, despite comments
within the paper to the contrary
3) Done in cucumber seedlings (and ONLY cucumber seedlings)
4) Pretty lame all-around.
Perhaps 30 years ago, this met the standard for that sort of thing, but to continue
its labeling in this manner for use on plants seems quite irresponsible. Although it
seems popular to cite its efficacy against plant viruses, it does not seem to be
supported in the literature. Its support, if any, seems to be from casual observations
and limited, informal studies. I would have to say that this really doesn't meet the
standards of scrutiny I'd like to see.
-AJHicks
Chandler, AZ
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