The technique used for maintenance and preservation of Trichoderma is

The technique used for maintenance and preservation of Trichoderma is Soil preservation.
Fungi belonging to the genus Trichoderma are used as successful plant growth enhancers, biostimulants, biofertilizers, and as effective biocontrol agents against various pathogens.
Trichoderma is stored by a long term storage method in envelopes kept in the container with a small amount of desiccant at -20°C.