Biological control of Sclerotinia sclerotiorum attacking soybean plants. Degradation of the cell walls of this pathogen by Trichoderma harzianum (BAFC 742). Biological control of Sclerotinia sclerotiorum by Trichoderma harzianum.

Two experiments of biological control of Sclerotinia sclerotiorum, one in the greenhouse and the other in the field, were carried out with soybean and Trichoderma harzianum as host and antagonist, respectively. Significant control of disease was achieved in both experiments, but there were no significant differences in plant growths. In the greenhouse, the application of T. harzianum as alginate capsules, increased the survival of soybean plants more than 100% with respect to the disease treatment. In the field, T. harzianum treated plants survived 40% more than those from the disease treatment, showing a similar survival level to control plants. Besides, a significant reduction (62.5%) in the number of germinated sclerotia was observed in the Trichoderma treated plot. Chitinase and 1,3-beta- glucanase activities were detected when T. harzianum was grown in a medium containing Sclerotinia sclerotiorum cell walls as sole carbon source. In addition, electrophoretic profiles of proteins induced in T. harzianum showed quantitative differences between major bands obtained in the media induced by S. sclerotiorum cell walls and that containing glucose as a sole carbon source.