Evaluación de la capacidad antagónica de Trichoderma spp. frente al hongo Rhizoctonia solani en Allium cepa L (Cebolla Roja).

Abstract

In order to evaluate antagonistic capacity of Trichoderma spp., against the fungus Rhizoctonia solani in Allium cepa L (red onion) due to the environmental problems caused by the constant use of agrochemicals test were carried out “in vitro” and “in alive”. Three strains of Trichoderma were isolated of onion, labeled as: Trichoderma from soil (TS), Trichoderma from Tricomix (TT) and Trichoderma from an unlabeled commercial product (TA), in the same way R. solani was isolated of onion plants that showed symptoms of disease. A completely random design was applied with three repetitions for each experimental unit. The in vitro test was prescribed by the percentage of mycelial inhibition (MI), as well as the degree of mycoparasitism according to the Bell scale and the type of antagonism that Trichoderma presents R.solani, in dual confrontations, however its antagonistic capacity was determined due to the provenance and type of strain, since the three strains evaluated, TS presented 55% of MI and physical type antagonism, whereas TA presented 45% of MI and a physical chemical antagonism and finally TT did not present a considerable MR and their antagonism was of a chemical type. In in vivo conditions in the red onion plants of the bourgeois variety, it was observed that the plants presented lower incidence of the disease, induction of growth of the aerial and root parts, increase of dry and fresh weight with respect to treatments inoculated separately with R. solani and the control. It is recommended to investigate other species of Trichoderma spp. isolated from agricultural soil used for growing onions.