B. subtilis bacteria produce a class of lipopeptide
antibiotics including iturins. Iturins help B. subtilis bacteria out-compete
other microorganisms by either killing them or reducing their growth rate
(CPL 2002). Iturins can also have direct fungicidal activity on pathogens.
B. subtilis products are made for many uses. For plant disease control,
these include foliar application and products applied to the root zone, compost,
or seed. When applied directly to seeds, the bacteria colonize the
developing root system, competing with disease organisms that attack root
systems (CPL 2002).