Trichoderma

Trichoderma harzianum, crustal ball Fungal ( Hypocreales )

Trichoderma is the anamorph of the genus Hypocrea. Trichoderma species are filamentous fungi that spread throughout the world in soil, plants that are decaying plant residues or wood. They are extremely important in the rhizosphere and interact between plants, microorganisms and other soil. By competition with other microorganisms, they are used more and more lately as an antagonist to phytopathogenic fungi. Hypocrea spp. forms the teleomorph ( teleomorph ) and is mainly found in wood. However, most Trichoderma strains exclusively form the anamorph.

Species

There are 33 known species. However, many strains are known and a reorganization of the species is discussed. In addition, in many species only the anamorphs are known. Important species:

• Trichoderma harzianum
• Trichoderma koningii
• Trichoderma longibrachiatum
• Trichoderma pseudokoningii
• Trichoderma viride

Macroscopic characteristics

In culture, the fungus forms a rapidly growing aerial mycelium. The mycelium is white and dense, but can be dyed green to greenish-yellow by the conidia when mature. They grow faster on PDA than on Sabouraud dextrose agar.

Microscopic characteristics

The hyphae are septate and hyaline. When conidia spores are formed phialidic on conidiophores with T. longibrachiatum and T. viride also chlamydospores. The conidiophores are hyaline and branched. the phialides are hyaline, bottle-shaped, swollen at the base and disposed at right angles to the conidia and may also stand in clusters, both individually. The conidia are 3 microns in size on average, one-celled, round to ellipsoid and mostly green. They are grouped in heads and the Phialidenspitzen.

Importance in biological control

The use of antagonistic microorganisms for the control of phytopathogenic fungi has been the subject of intensive research. One of the most studied antagonists in relation to biological control is the type Trichoderma.