levels of an extracellular exochitinase. Diffusion of this enzyme
catalyzes release of cell wall fragments from target fungi and this,
in turn, induces expression of fungitoxic cell wall degrading enzymes
(8) that also diffuse and begin the attack on the target fungi
before contact is actually made (42,48). These cell wall fragments
are highly potent inducers of enzymes and induce a cascade of
physiological changes within the fungus, including an enhancement
in Trichoderma growth. This system will be described more
fully in this session by Lorito. Thus, there are numerous ways by
which Trichoderma spp. attack or otherwise directly inhibit other
fungi.