ABSTRACT
The objective of this work was to evaluate the ability of Trichoderma asperellum isolates and their culture filtrates to control Lasiodiplodia theobromae in vivo and to promote the growth of pecan seedlings. Two experiments were carried out, both in a greenhouse. In the first experiment, the aerial part of the plants was sprayed by biological control treatments and, 14 days later, the pathogen was inoculated into the stem, through injury. In the second experiment, the substrate was moistened with biological control treatments and 14 days later the pathogen was inoculated following the same methodology as the first experiment. The following parameters were evaluated: length of the aerial part, stem diameter, fresh mass of the aerial part and the root, dry mass of the aerial part and the root, incidence and severity of the disease. The comparison of means was performed using the Skott-Knott test at a 5% probability of error, using the SISVAR software. In both experiments, the greatest responses were obtained in the growth parameters evaluated in the treatments with the culture filtrates and with the spore suspension in relation to the treatment inoculated with the pathogen without the use of biological control treatments. These treatments also reduced the incidence and severity of stem canker in pecan seedlings, and the best treatment varied with the form of application. The isolates of T. asperellum and the culture filtrates stimulated the initial growth of the plants, decreasing the incidence and severity of stem canker in pecan plants, regardless of the form of application.
Keywords
Trunk canker;
Lasiodiplodia theobromae
; Biological control; Disease management