Biocontrol de Rhizoctonia solani y Fusarium sp. con microencapsulados de bacillus subtilis y su efecto en crecimiento y rendimiento de tomate (Lycopersicon esculentum Mill.)

Abstract

The research hypothesis is that rhizobacteria of the genus Bacillus have the property of promoting the growth of some plants, being antagonists of phytopathogens, and being microencapsulated in a biopolimeric matrix. There fore, the objectives of this assay were: 1) adapting a piece of equipment, and evaluating a technique to elaborate sodium alginate microcapsules in which rhizobacteria of Bacillus subtilis could be incorporated; 2) analyzing the biocontrol against soilborne phytopathogenic fungi, and 3) determining the promotion of the growth of tomato plants in greenhouse conditions. Strains of B. subtilis, identified as B1, J1, M2, and a mixture of them all were used; the microcapsules containing the bacterial strains were attached to tomato seeds of Floradade cv. Once the seedlings sprouted, a second application with B. subtilis was done to the flowerpots previously inoculated with Rhizoctonia solani and Fusarium sp. fungus propagules and spores. The analyzed variables were: inci dence and severity of illness; plant growth; aerial dry and root weight and; foliage area and fruit yield. The results showed that the device built, and adapted for microcapsule elaboration was efficacious; B. subtilis strains showed its biocontrol activity when they reduced the incidence and severity of the illness by significantly inhibiting the activity of the phytopathogens; moreover, the B. subtilis microcapsules stimulated plant growth, and fruit yield. On the basis of the obtained results it may be concluded that the microcapsules containing bacterial strains can be an efficacious biocontrol agent against soil pathogens, and can have a biofertilizing activity, because they notably stimulated the growth, and yields of tomato plants, as compared with those of the witness treatment. It is suggested to validate these results in the field to corroborate the effectiveness of the process shown in this work.