Trichoderma is typically a root-colonising, saprotrophic fungus, mainly feeding on dead organic matter. Still, it also has parasitic behaviour against other fungi by invading their hyphae and degrading their cell walls with enzymes. Like this, they can use them as nutrients, strengthen the root system and boost photosynthesis.
With this ability, some trichoderma species can be an agent of biological control in agriculture as an effective bio-fungicide and bio-pesticide.
The Trichoderma fungi are present in nearly all soils, where they are frequently the prevalent culturable fungi. You also find them in other habitats.
Sources
ReThink – Microorganisms
Wikipedia – Trichoderma 
Cornell.edu – Biocontrol – Pathogens – Trichoderma
May 2025, RETHINK
