Abstract: Methods and compositions for effecting plant root infection with microorganisms, especially vesicular arbuscular mycorrhizal (VAM) fungi are disclosed. The method relies on a root baiting concept whereby the roots of a plant are caused to grow towards and/or through a material which contains an inoculum of the microorganism. Typically bead-like materials are produced which are comprised of (1) a bait material for which roots have a natural affinity; (2) an inoculum of a microorganism which can infect plant roots and improve their growth and/or health; and (3) a carrier material that supports and localizes the bait and the inoculum. The bait may be water or another suitable material such as a plant growth regulator and the carrier is typically a non-phytotoxic crosslinked polymer especially a water absorbing polymer. The compositions are placed in the vicinity of the plant roots. The bait draws the roots towards the composition to permit infection of the roots with the microorganism.