1)competition

Trichoderma harzianum grows rapidly around plant roots and leaves, preempting the planting sites on the surface of the plant,
forming a protective layer on the surface of the plant, preventing pathogenic microorganisms from contacting the root system and
the surface of the leaves, so as to protect plants and roots from Infection by pathogenic bacteria.

2）Parasitism

Trichoderma harzianum secretes certain metabolites to make it grow toward the host. Once the host is recognized by Trichoderma
harzianum, a parasitic relationship will be established, and Trichoderma harzianum will use the host as vegetative growth and
reproduction, thereby causing the bacteria to disintegrate and die.

3）Antibiotic       effect

During the growth process, Trichoderma harzi can also secrete some antimicrobial substances to prevent the colonization of
pathogenic bacteria. These substances can directly inhibit the growth and reproduction of pathogenic bacteria.

4）Induce plant resistance

The colonization of Trichoderma harzianum in the plant rhizosphere and the secretion of various plant elicitor analogs during its
growth can induce the activation of the plant's anti-epidemic system, thereby protecting the plant from being infected by a large
number of pathogenic microorganisms.

5）Additional

In addition to the biological control function, Trichoderma harzianum can also promote the growth of crops: this is mainly due to
the role of some secondary metabolites produced by Trichoderma harzianum, these substances mainly include: auxin, gibberellin,
Cytokinin, abscisic acid, etc.