This article was just posted in the compost tea group and while it is over a year old, I hadn’t seen it before and it is amazing how little we know about plants and microbes.  However, we are making progress.
From It Takes a Community of Soil Microbes to Protect Plants From Disease

… The sugar beets’ health followed the typical arc of plants in disease-suppressive soil: they enjoyed a few good years, then they succumbed to disease, followed by healthy beets again as pathogen-fighting microbes were activated and the soil became hostile to R. solani. To return the favor, the sugar beets funnel about a fifth of their photosynthetically captured carbon through their roots into the soil to fuel the microbes.
New research reveals that it takes a community of soil microbes, not just one or two, to protect crops. The top image is a healthy sugar beet field. The bottom image is a field of sugar beets that is infected with root fungus:
New research reveals that it takes a community of soil microbes, not just one or two, to protect crops. The top image is a healthy sugar beet field. The bottom image is a field of sugar beets that is infected with the root fungus.
Disease-suppressive soils are quite common, and scientists have identified some of the microbes involved in this underground immune system. But they don’t know all of the microbes that participate.
To find out, the scientists used the PhyloChip, which is a credit-card sized chip that can detect the presence of 59,000 species of bacteria and archaea in samples of air, water, and soil without the need of culturing. It was developed at Berkeley Lab to rapidly identify not only the most common and abundant organisms in an environmental sample, but also very rare types that are present in extremely small numbers. It does this by comparing a DNA sequences unique to each bacterial species with over one million reference DNA targets on the chip. …

The discussion in the compost tea group revolved around adding microbes NOT present in your soil:

… Assuming you make your own Compost, then you’ll be using greenery from your soil. This means any bacteria missing in the soil will also be missing in the Compost.  …

This is what Tim Wilson had to say:

It is the composting process or vermicomposting which creates the microbial makeup, not just the plant material used. Of course if composting, it is necessary to provide the correct C:N ratio.
If using composting worms, just by introducing your vegetative scraps along with a carbon source like cardboard and maybe some peatmoss, one is pretty much assured of a highly diverse population of bacteria/archaea, protozoa, fungi and nematodes.

C:N ratio is the carbon to nitrogen ratio, see http://www.composting101.com/c-n-ratio.html.   I looked at our worm bins today and they have been way too wet, seriously neglected because we need to clean out the entire little adobe addition that houses the worms and all our seedlings.   All the food plants are out and I set off a bug bomb because it was infested with spiders, lately I’ve seen everything from black widows to a huge tarantula.  So now we just have to clean and organize everything.  And I’ll get the worm bins back in shape.
I’m looking forward to a clean place to start winter veggies and we’re going to have to build a better tea brewer.