First of all, all mycorrhizal products will have carriers. This is for the propagules because if you didn’t have a carrier your propagules would probably not survive. Next, Mykos WP is actually lower in concentration than their granular version and the carrier there is Clay. DYNOMYCO has clay and vermiculite as the carriers, but has a far higher concentration than the rest.
As for the other two products that you mentioned, their carriers are active ingredients, and their concentration of mycorrhizal fungi is very very low and if it’s not doing the work, it’s the active ingredient carriers inside it that are. Thanks
DYNOMYCO has the greatest concentration of mycorrhizal fungi per plant at the lowest cost per plant