Effect of Trichoderma strains on the growth of tomato plants in greenhouses and their aptitude to colonize roots and substrate
Fungi in the genus Trichoderma, known since 1887 for their antagonistic properties, have been used as a biological control organism against several plant pathogens. Recently, studies showed the aptitude of Trichoderma to stimulate plant growth. Thus, the effect of six strains of Trichoderma on greenhouse tomato growth and yield was studied. The results show that all T. harzianum strains stimulated tomato growth, in particular the shoot and root weights, whereas T. viride did not have a significant effect. The effect of Trichoderma on leaf disease incidence was very clear since tomato leaves were completely protected (100%) by some T. harzianum strains. Root colonization by the various strains of Trichoderma did not differ significantly between the T. harzianum strains (86 to 100%), whereas it was significantly lower for the TV1 strain of T. viride. Also, Trichoderma strains maintained a high concentration level in the rhizosphere compared with the controls.