The active ingredients in Sabrex are three hybrid strains of trichoderma that were originally developed and tested by Cornell University scientists.  Trichoderma is a fungus that colonizes the roots of the host plant.  It stimulates root growth and protects against root diseases.  Trichoderma is found naturally in the soil and has been there for thousands of years.  The guys at Cornell found that by crossing different lines of the fungus, they could create a hybrid fungi that colonized more rapidly and offered more protection than the native trichoderma.  

This research began back in the late 80's and has since then created hundreds of hybrids.  The first one to hit the market in 1997 was T-22, which stood for trichoderma hybrid strain # 22.  It only contained one strain, but was a break-through.  Sabrex was the first to be formulated with graphite and talc (to make application easier) and contains several different strains with each having a specific job in protecting the host plants.