MASHUP
Member
Here's the deal, from someone with a horticultural background.
Most likely scenario is the roots suffered what equates to a "burn", most likely from excess nutes. Any attack from pathogens would set in gradually, this seemed to happen rapidly.
Once the sensitive roots are damaged they must be broken down, this is where the organisms be them beneficial or not come into play. With this much dead root material at once even the best inoculants and enzymes couldn't keep up.
You just need to trust in the less is more approach and you will rock that shit. Dynagro should do well, as would any nutes at a low enough concentration, especially to start out. I'm less familiar with Guardian Angel but I'm sure it will do it's job. All of these biologicals are designed to deal with root exudate ( sugars & sloughed off cells produced by the plant to feed soil microorganisms ) and would be overwhelmed by the decaying root matter. Don't be too rattled by the crash landing, you're about to fly like an eagle.