What is Trichoderma?
Trichoderma species are non-pathogenic fungi often found in soil as well as in association with plants. These green coloured fungi are well known for their anti-fungal and/or plant-growth-stimulating effects.
For these reasons, several strains of Trichoderma have been developed into biological control products which are used all over the world to combat fungal plant diseases on various crops. Most of these biological control products are from the species Trichoderma harzianum, T. viride and T. atroviride.
WHERE DOES TRICHODERMA OCCUR NATURALLY?
Trichoderma species are adapted to diverse habitats and are naturally found in soil, decaying wood, compost, roots and above ground plant organs. Some Trichoderma species have been associated with wounds on aerial parts of woody plants, either originating from aerial inoculum or from within the plant. Trichoderma species have been isolated from healthy South African grapevine wood suggesting that they may be present inside grapevine wood without causing any symptom or disease, a so called endophyticfungus (Halleen et al., 2003).In the soil, Trichodermaspecies are able to grow and reproduce while competing with other soil microorganisms.Trichoderma colonise individual plant roots or entire root systems without any detrimental effect to the plant. In fact, Trichoderma can also elicit plant defense responses and increase plant root growth (Harman, 2000; Harman et al., 2004). It is now being accepted that Trichoderma species have evolved an opportunistic, non-pathogenic and symbiotic relationship with plants. Due to their cosmopolitan nature, strains of Trichoderma can be selected that are adapted to a particular habitat for use as biological control agents against fungal pathogens or as growth promoting factors.
HOW DOES IT PROTECT PLANTS?
Trichoderma strains can directly or indirectly exert biological control activity against fungal pathogens (Benitez et al., 2004).Trichoderma can attack...