I did find one case where a trial with Actinovate was fairly
successful in soil (rather than in sterilized container mix),
which was a test on the efficacy of Actinovate+chitin to
control northern root knot nematodes (Meloidogyne Hapla).
One of the test sets was conducted on cups filled with
60% organic soil and 40% sand. It was not total eradication,
but impressive nonetheless. It is one of several reports
included in this document:
http://www.pubmedcentral.nih.gov/art...?artid=2586450
(Search for Actinovate in that page to find the summary.)
If Actinovate's bacteria would survive in my garden soil and
control verticillium, that would be great. The only test results
I found were on verticillium infecting potatoes, where there
was no detectable disease suppression using Actinovate.
I do not know whether the verticillium population had defenses
against Actinovate's particular strain of bacteria or if the soil
environment was simply friendlier to verticillium than it was to
Actinovate. (Probably cold and wet if the verticillium was there
in the first place. I seem to remember reading that Actinovate
needs a soil temperature above 45F/7C to be effective.)
I have been leaning more toward plant extracts that interfere
with verticillium reproduction and metabolism. Extracts are
not alive, so they can't be killed off by other soil organisms
(although they also do not "grow along with the roots", an
upside of a live biocontrol organism), and their action is not
temperature dependent. The only questions are what
concentrations one needs of which extracts to do the job
and how long they are effective before they are broken down
by organisms in the soil.
I am trying a really primitive approach on one plant of a cultivar
that I know is susceptible in soil that I know was verticillium
infected last year: a lime-sulfur soil drench. I happen to have
some around, so finding out if it will supress verticillium is
more or less free.